# Timber house extension.



## skipdiver (5 Jul 2008)

After having my workshop built from breeze blocks,i started to think to myself why i didn't just build it from timber.Would have been quicker,cheaper and more aesthetically pleasing but let SWIMBO and security fears sway my judgement.It's done now so that's that.

This got me to thinking i could redress the balance somewhat by building my utility/shower room house extension from timber.Been in building/joinery trade all my life and have worked on all sorts of projects but apart from the odd timber building for site offices or garden chalet,never built a domestic extension from anything other than the standard brick/block construction.

So my question is,can i do it from a building regs point of view.Will my local planning officer be receptive to this,anyone else done it?I can find out next week sometime but out of town most of the week and a bit impatient to know.Will have to research it i suppose.

Any info appreciated.


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## RogerS (5 Jul 2008)

There are plenty of timber-framed suppliers out there such as Border Oak so the principle is well established and accepted. Usual provisos apply such as adequate foundations etc. Simplest route would be to use the same timber dimensions as the established boys (such as Border Oak - no affiliation!). 

Best plan though is to speak to your local BCO to see what they require. Their reaction will depend on where you live. Middle of London might see a bit of scratching of heads but elsewhere in the country such as Herefordshire shouldn't be a problem. 

Practical points. Green oak - shrinks - live with it! How to infill the panels ? There is some magic stuff that you put into a groove rebated around the internal perimeter of each oak frame and that expands to fill the gap left as the green oak shrinks. Do you want to see the oak frame internally? If so then that means you will need larger frame dimensions to allow for all that insulation that they want these days.

Finally remember the four golden rules of oak frame buildings

Rule 1 - all oak frames will leak at some time 
Rule 2 - old oak frames will leak even more
Rule 3 - lime mortar is excellent
Rule 4 - mastic for sealing oak frames doesn't work

DAMHIKT

Cheers

Roger


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## BradNaylor (5 Jul 2008)

Steve,

I've been thinking exactly the same thing.

I'd like to add a single storey exension to the side and back of our house, and insead of getting a builder in was wondering about the feasibility of building it myself out of prefabricated plywood and timber panels made in the workshop and bolted together on site. 

Some cladding, some windows, a tiled roof and Bob's your uncle!

This seems to be a fairly standard approach in America and in other parts of Europe. Here though, we appear to be obsessed with brick.

I guess the BCO is the first port of call?

Dan


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## skipdiver (5 Jul 2008)

Thanks for the reply chaps.Was thinking more along the lines of CLS and ply/OSB for the structure.Green oak would be totally out of keeping with the house and the area.We keep getting told that concrete and concrete products are not very environmentally friendly and of course most timber comes from renewable sources now so i don't see why this would be a problem.Suppose it all depends on how forward thinking local councils are nowadays.

I know that timber framed houses are now an accepted building medium.So why not a simple extension?

I've got my juices flowing now.Going to do some research.


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## BradNaylor (5 Jul 2008)

Let me know how you get on, Steve.


Cheers
Dan


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## skipdiver (5 Jul 2008)

Will do.


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## CNC Paul (5 Jul 2008)

Steve,

I am planning on building a house in Ireland using structural plywood
cut on a CNC, similar to one a friend of mine in the US has just cut
(600 sheets).

http://momahomedelivery.org/

Click on the West lot video.

Mine will be built in 2.4m x .6m modules that are screwed together and filled with Warmcell 100. It is a very quick 
and clean way to build as well as being kinder to the invironment.

As you have the skills you won't need to call in a brickie and a plasterer 8) .

Paul


Paul


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## dickm (5 Jul 2008)

I actually live in an entirely timber-built bungalow. It was commissioned by the previous owner from a Swedish kit building company (Hedlund) and like most Swedish stuff is highly insulated, triple glazed etc. Great to live in, and for a whole house, probably cheaper as a kit than attempting to make yourself from scratch?
From a planning point of view, Scotland is possibly more receptive to timber construction than other parts of the UK.
BUT, most mortgage companies and insurers do the "sharp intake of breath" when you ask about financing/insuring such things. Probably not the cheapest or most competent, but we finally got insurance with MoreThan.
Dunno how your mortgage/insurance would be with a timber extension, but from every other viewpoint, I'd recommend it.


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## skipdiver (5 Jul 2008)

Very impressive.Bit like SIPs (structural intergrated panels) which i have researched for my eventual housebuild which i hope to do one day in the future.

I've no doubt i have the skills Paul,it's more the permission side and what is allowed that i'm researching.Been on the planning portal and it says walls "can be constructed in various ways using timber framing or masonary construction" It then goes on to list various methods of constructing masonary walls but makes no more mention of timber construction.

It also quotes fire resistance,thermal resistance,weather resistance and weight loading but makes no more mention of timber options.

Suppose it's down to the planning office next week.


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## skipdiver (5 Jul 2008)

Thanks Dick,seen a few progs on telly utilising timber build and hope to build my own house one day.Don't know how to go about doing an extension on a brick built 1930's semi in the meantime.Whether i would be allowed.


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## CWatters (5 Jul 2008)

Many houses these days are built using a timber frame clad with brick. Suggest you drive around a few new estates.

The building regulations require walls to meet specific insulation U-Values. All the companies that make insulation have guides on their web sites showing how to use their products in timber framed houses. These have useful cross sections in them.... Here is one example but see also the sites for Celotex and Kingspan etc...

See page 3 in particular...

http://www.rockwool.co.uk/graphics/RW-G ... /Flexi.pdf


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## skipdiver (5 Jul 2008)

The point is,i dont want brick.I know new houses utilise timber framing now but want to know the feasibility of building an extension entirely from timber attached to what is a normal brick 30's semi.Will planning let me?If so,then i will go into the why's and wherefore's.

Thanks for the replies once again.


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## Jake (5 Jul 2008)

Is it going to be within your permitted development limit, sizewise?


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## Digit (5 Jul 2008)

I also live in an entirely timber building and the local planners simply don't like it. I was denied any form of grants unless I clad it in brick or block.
Norwich Union will offer insurance.

Roy.


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## skipdiver (5 Jul 2008)

Yes Jake.,it will be within my permitted development rights.If i build it from masonary then there will be no problems.It's the method f build i am more concerned with.

As Roy has pointed out,authorities don't seem to like them for some reason.Backword country we live in.


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## Jake (5 Jul 2008)

Planning have no say, then. 

The only time they is with buildings in a conservation area, where some facing materials, including timber, are excluded from permitted devt rights. I think I know from a recent thread that you're not!

BCO is your only issue - but they can't stop you building with a timber frame - they might get their knickers in a twist about calcs etc, but as long as you can show them it is structurally sound they can't stop you no matter how much they moan.


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## skipdiver (6 Jul 2008)

That was my thinking Jake but i'm sure they will try and get me some other way.Fire resistance and proximity to neighbours is my biggest worry.I'll try and see what happens.


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## RogerS (6 Jul 2008)

Steve

I had a quick gander at my Building Regs bible and the bad news is that there is no mention of wall construction other than brick etc. That's not to say that you can't use timber etc but I suspect you will need professional input from structural engineer. How about contacting the manufacturers of SIP panels? And wasn't there a house on Grand Designs made in this way? Huff Haus IIRC.


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## skipdiver (6 Jul 2008)

On the latest planning portal it does mention timber as a material for external walls but doesn't go into any detail.I've read a lot of stuff on SIP's as i may go this route when(and if) i get round to building a retirement place one day.This extension(if it gets off the ground) will be framing and Sterling board.Obviously when house packages are designed by kit house companies all the structural calcs will be done at source and tested to satisfy the building regs.

I have also seen on Grand Designs all sorts of houses built entirely from timber incorporating "I" beams and glulam and all sorts of timber engineering.I even saw one house sat upon a huge wooden beam that was fabricated from wooden chippings but i cant remember the name of the product.

I think i will go and have a look on the TRADA website,see if they have any info.


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## skipdiver (6 Jul 2008)

From what i can gather,you can build it from timber if you meet the criteria of building control.

Found some interesting stuff at www.natural-building.co.uk under panatex.

Sorry,don't know how to do links.Not keen on 'puters.


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## Digit (6 Jul 2008)

My place is single story Skip, so structural problems are of a minimum.
Bit like a large garden shed really! :lol: 

Roy.


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## skipdiver (6 Jul 2008)

OOOOH! the link faeries have been in.

Thanks.


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## skipdiver (6 Jul 2008)

Just tried that link and it doesn't work.It should be building not build.I'm a plank.


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## adzeman (7 Jul 2008)

It is all down to what area of the country the building/extension is situated. Building Control will not be a problem they will advise on the technical aspect of what you can or cant do.
Planning are the people to contact and they will expect you to produce elevations/design in keeping with the area where the building/extension is. OR, it will compliment the area it is situated. Where I work at present East Sussex it would not be a problem as there are many timber framed buildings in the County. I have been involved with new timber buildings in Lewisham, Forest Hill to be exact, part of a co-operative self build. There was no problem in getting them past by planning, in fact positive encouragement. If you are extending an existing brick building then you have a problem in extending it as a timber (looking as) extension. You could timber frame it but it will still be required to be faced in a matching brick unless you can demonstrate your design will enhance the general aspect of the area. For that you will require proffessional advice. example if your extention is on a Council Estate, no chance or lets say in a stone village of the Dales no chance. On the outskirts of Lewes, every chance.


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## Jake (7 Jul 2008)

adzeman":1db6f0v4 said:


> It is all down to what area of the country the building/extension is situated. Building Control will not be a problem they will advise on the technical aspect of what you can or cant do.
> Planning are the people to contact and they will expect you to produce elevations/design in keeping with the area where the building/extension is. OR, it will compliment the area it is situated. Where I work at present East Sussex it would not be a problem as there are many timber framed buildings in the County. I have been involved with new timber buildings in Lewisham, Forest Hill to be exact, part of a co-operative self build. There was no problem in getting them past by planning, in fact positive encouragement.



Just up the road - I'm in New Cross - Telegraph Hill - where there's another cluster of timber frames you may well know of. In fact, there's a fine post-war tradition of such buildings in SE London, as you probably know.

What you say above is all very true, but you go on to say:



> If you are extending an existing brick building then you have a problem in extending it as a timber (looking as) extension. You could timber frame it but it will still be required to be faced in a matching brick unless you can demonstrate your design will enhance the general aspect of the area. For that you will require proffessional advice. example if your extention is on a Council Estate, no chance or lets say in a stone village of the Dales no chance. On the outskirts of Lewes, every chance.



That's only the case if the extension requires planning permission (or rather isn't automatically deemed to have pp) because it is larger than the permitted volume under the GPDO. 

If the extension is within the permitted volume (which is the case here, see above) the planners have no say at all, and no legal right to intervene in any way. It doesn't get anywhere near them. 

This is all unless, as I've said above, the land is in a conservation area, etc, where certain facing materials, including timber cladding, are excluded from deemed consent under the GPDO. In that case an extension of any size in timber cladding would need a planning application - at which point everything you say applies again.

Skipdiver's problem is limited to his BCO.


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## adzeman (7 Jul 2008)

I know them well Skipdiver I was a surveyor for the Council for 12 years in the area. Planning regs are quite involved, my advice would always enquire and not just go ahead willy nilly as they can make you pull it down for non compliance. Also always obtain there ruling in writing as I have experiance of them changing there mind. When I need planning permission or Building Control advice I always call in person (after making an appointment) say I have a problem could they help or assist me. I then find they do their best in solving or providing a solution. Ignore them and then they find out what you have done is always non productive. Its not a free service, you are a customer and should expect some satisfaction for your cost.


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## Jake (7 Jul 2008)

adzeman":3vo40gwa said:


> I know them well Skipdiver I was a surveyor for the Council for 12 years in the area.



I'm Jake, the OP is Skipdiver. Thought you would - they are a fantastic little community development, always looks great from my passer-by's perspective. 



> Planning regs are quite involved, my advice would always enquire and not just go ahead willy nilly as they can make you pull it down for non compliance. Also always obtain there ruling in writing as I have experiance of them changing there mind.



I would (and have) applied for a cert of lawful development in this kind of situation, but that's me being cautious. 

Generally, very good advice - to talk to them - but in this situation you could (and I would) adopt a less deferential attitude, as they have no lawful authority to intervene. The GPDO is crystal clear on that, providing Skipdiver is sure that it falls within the permitted devt volume (checking those carefully, and taking into account any existing post-1948 extensions which may have eaten into the allowance).


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## adzeman (7 Jul 2008)

Sorry Jake my mistake. Just to re-cap [So my question is,can i do it from a building regs point of view.Will my local planning officer be receptive to this,anyone else done it?]
RogerS was 1st to reply saying yes but BCO would probably scratch their heads.
Skipdiver stated he was going down to Planning next week.
What I have tried to do without going into detail and not knowing the full circumstances of skipdivers project is answer his questions to the best of my experiences.
Yes skipdiver can do it from a BCO building regs point of view.
In response to RogerS, No they would not scratch their heads in the centre of London. Skipdiver should take a trip down to Planning and obtain their advice before he starts spending money.
Yes you are correct Jake with your correction but I was trying to be general rather than specific. What I can be specific about is the road of bureaucrats is scattered with the wrecks of lost projects due to ignoring Building Control or Planning. These are two totaly different departments by the way but in my experience staffed by people who just want to help. Though I was a surveyor for Lewisham I was not part of Building Control or Planning and for the projects I dealt with I still had to obtain Planning and Building Control approval some I won some I lost.
[/quote]


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## skipdiver (7 Jul 2008)

I have news.

First of all thanks for the input Jake and Adzeman.I am au fait with planning and building regs because i work in that arena.I don't need planning as i still have my 70 cube PDR to play with.

Been and helped my mate today who is building a sun room and needed a hand with the footings.BCO has made him dig then 2mts deep because of a nearby hawthorn tree.The bungalow the sun room is attached to has footings 18" deep and has been there unmoved for 50 years.Ridiculous IMHO but i digress.

The inspector turned up this afternoon to check see how we were getting on and i had a word with him about my extension.No problem was his reply.No reason why i can't do it and he thinks it will get more and more popular as a building medium.He gave me the name of a colleague who works as an architectural designer and planning consultant who should be able to give me the lowdown on building techniques and draw up plans for an application should i need one.He also said that i could do it on a building notice if i had some drawings with calcs on.

BTW adzeman,the finish will be render same as the rest of my house.


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## Digit (7 Jul 2008)

He might be an expert on building Skip but his knowedge of trees is a bit suspect.
Hawthorn have small root balls and are not deep rooted, I suspect that you and your mate passed the roots at less than one metre. They are not known to drain the land of moisture either, which is why they survive for so many years on hedge banks.

Roy.


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## skipdiver (7 Jul 2008)

My thoughts exactly Roy and the inspector agreed it is ridiculous.He said we probably passed the routes at 2ft but that's the way it is going.buttocks covering excercise.I said hawthorn tree but it was more a hedge and there were oak trees behind that,some old,some newly planted but it was the hawthorn that got mentioned.Basically any greenery near any building project now gets the same treatment.It was either 2mt deep footings or the whole site being dug out to a metre deep and filled with concrete and re-inforcing mesh.We have 7 cube of concrete coming tomorrow to support what is a glorified conservatory.Crazy. If i remember i will take my camera and post some pics.


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## Digit (7 Jul 2008)

Rules, for the guidance of wise men and the control of fools!
What ever happened to the wisemen.

Roy.


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## dickm (7 Jul 2008)

Digit":3sttzscb said:


> He might be an expert on building Skip but his knowedge of trees is a bit suspect.
> Hawthorn have small root balls and are not deep rooted, I suspect that you and your mate passed the roots at less than one metre. They are not known to drain the land of moisture either, which is why they survive for so many years on hedge banks.
> 
> Roy.


Show me one who <does> have knowledge of trees! When we had our extension built on the last house, there was a DWARF conifer in neighbour's garden that was about 3m from the corner of the extension wall. BC was insisting on 2m foundations until I rang the neighbour at work and went into his garden with a saw...........


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## Digit (7 Jul 2008)

Which is also ridiculous Dick because if a tree is drawing water from the ground removing it alters the ground water level in that area. In fact official guides in the past have empahsized that very point. 
But a dwarf conifer makes you wonder about the level of competence don't you think?

Roy.


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## skipdiver (5 Feb 2009)

6 months down the line,i have now started my extension.The footings are being dug between snow storms and i was going to forget the whole timber idea and get my bricky mate to throw up a block and render shell because work commitments have kept me away from home.Work has eased off a bit now and am starting to think about the timber frame idea again.When the inspector comes to check the footings,i am going to run it by him and see what he says.

Will let you know what he says in due course.


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## Benchwayze (5 Feb 2009)

skipdiver":2xb5gh0a said:


> As Roy has pointed out,authorities don't seem to like them for some reason.Backword country we live in.



Hi Skip, 

Haven't you heard of Health and Safety and all that Nanniness? 
:lol: 

Oh me Gawd... You can't use wood! :shock: It might burn down! :shock: 

Seriously, I wonder why we lag so far behind other countries in building timber houses? Also, I just don't know why builders don't dig a big 'ole first and build the house on top of that. Then we'd all have three levels. 

Not that it would help me now, but it's something that needs to be thought about for future new buildings, especially where the ground is suitable. 
Wooden houses = more work for woodies! 
Maybe that's it... The brick companies don't like the idea! 
8)


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## Benchwayze (5 Feb 2009)

Digit":3gfuyvyt said:


> Which is also ridiculous Dick because if a tree is drawing water from the ground removing it alters the ground water level in that area. In fact official guides in the past have empahsized that very point.
> But a dwarf conifer makes you wonder about the level of competence don't you think?
> 
> Roy.



To kill a tree...

Get a powerful rifle equipped with a telescopic sight and a silencer
then, when your wife isn't looking, fire some slugs into the trunk,
near its base.

Slugs are ravenous creatures and they will quickly eat their way
through the tree then .....

Please don't forget to give the mandatory cry of 'Timber!' before it
comes crashing to the ground.

Whatever you do .... 

Do not start laughing or that could give the game away.

That's how I would do it.

Lumbering Jack

http://answers.google.com/answers/threadview?id=785639


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## Digit (5 Feb 2009)

I'll try to remember that! :lol: 

Roy.


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## chipchaser (6 Feb 2009)

Skipdiver, don’t give up on the timber frame idea too easily. Your timber frame extension can be erected and weathertight much more quickly than what is called traditional construction in UK. 

Seems to be some interest but also some questions about timber frame on this site. Many US and northern European homes are timber framed and clad using the simple ”balloon frame” or the stressed skin panel methods. There is a long tradition of timber frame housing in UK although there is still resistance to the modern softwood framed systems based on ignorance in some quarters. If correctly designed there should be no problem with satisfying Building Control but Planning Officers can occasionally be difficult due to prejudice and misconceptions. I believe some of the prejudice is being softened by the current interest in green issues as timber frame can be much more energy efficient both in embodied energy and in running costs.

In the 1980’s I worked on several timber framed buildings the frames being manufactured for us by Potton who are still in business. But we don’t have to buy factory made frames, they are simple to make at home. As someone posted earlier, just like sheds but with a bit more design detail. Properly designed and detailed they should be good for at least 60 years.

One of my heroes is Walter Segal, sadly no longer with us, but a pioneer in self build using a system of framing and standard sized sheet material built off lightweight pad foundations. Here is a link to a site to a site run by the Walter Segal Self Build Trust:
http://www.segalselfbuild.co.uk/home.html

and a Wiki which has useful links:
http://en.wikipedia.org/wiki/Walter_Segal

There is a list of books that might be useful or interesting at this link:
http://www.biy.moonfruit.com/#/usefulpu ... 4515635744

I totally agree with earlier comments about Building Inspectors and foundations. Unfortunately, they have to protect their employers from litigation by assuming the worst possible case. There are often cheaper sensibly scaled solutions but Building Control require them to be proved by Engineer’s calculations so if it does fail the Council is covered and the Engineer or his Professional Indemnity Insurance picks up the bill. On small domestic jobs it is often easier and quicker to simply do as the BCO requests rather than lose time and money getting Engineer’s calculations and approval by the Council. 

Regards

Graham


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## Krysstel (6 Feb 2009)

Been following this thread with interest for a while and thought I'd drop in now. 
I live in a country where everything is built in wood. The climate dictatates that homes are built to take huge swings in temparature (+30 in summer to -30 in winter), (semi)permafrost to up to 1,5 meters depth, and rain at least on par with the UK. As a consequence, Scandanavians are perhaps world leaders in design of timber framed houses that last but at the same time are not expensive or time consuming to build.
I hear a lot of talk in the UK about plywood skins, SIPS- panels etc, but in Norway such building techniques are unheard of.

In short, this is a typical/traditional construction method used over here :-
1. foundations (simple footings are not good enough against the permafrost)
2. Softwood studwork frame with 60-60 centres. Now usually 150x48 but previously 98x48.
3. Outer skin in water resistance plasterboard or similar screwed directly to the studwork. The purpose of this is both to stiffen the frame and more importantly as a wind barrier. Previously they used asphalt paper as the wind barrier and stiffened the framework diagonally with steal strips, but the stiff board method is simpler and quicker.
4. 23x48 softwood strips over the studwork uprights, outside the wind barrier skin. This seals all the joints between the plasterboard sheets and creates a gap of still air between the cladding boards and the wind barrier.
Any moisture that gets behind the cladding then has the possibility to dry out instead of rotting the cladding from the inside.
5. Stained softwood cladding.
6. Internally, 15-20cm insulation in the studwork with 0.2mm plastic sheeting over. The plastic sheeting acts as a moisture barrier to prevent warm moist air inside the building from penetrating the construction. This can cause problems when it meets colder external temperatures, condences and rots the wall from the inside !
7. Roof construction uses much the same techniques as the walls but utilises some kind of waterproof wind barrier under the roofing tiles.
8. Openings in the studwork frame for windows and doors are made with a 1 cm gap all round that is then sealed with expanding foam on the outside and filled with insulation to the thickness of the walls on the inside. Windows are of course double (or triple) glazed, usually with an argon gas filling.

Now I realise that a lot of this would be over kill in the UK (insulation levels, window type etc) , but the basic method is sound and well tried and would work in the UK.


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## Mike Saville (6 Feb 2009)

A quick note on my experience.. . . 

We have received planning permission for a 2 storey rear extension, loft conversion & garage conversion. The size of the extension is sizeable (I would estimate the size of the normal 3 bed new build semis you see around the country). The extension will tie onto a 1900 stone house.

I called building control about construction choice. They said they had no preference as long as it met the regs. I then called planning who advised that as long as the external finish (render) was the same as on the permission then they didn't mind which construction I use.

I've since had quotes and brick and block comes in around double timber frame for the basic structure (get's me up to first fix stage). The timber frame companies all offer structural drawings and calcs in the price and all offer significant insulation advances on brick and block.

IMO, local builders don't want to do timber frame as that's not what they're used to. Go to the specialist timber frame co's however and my experience so far is a superior product for less money.


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## Krysstel (6 Feb 2009)

By my experience, the timber framed method I described is probably completely within the capabilities of most people for a single storey extension (those being considered by "skipdriver" & "Dan Tovey" for instance) but obviously things get a lot more complicated with larger constructions over several floors.


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## chipchaser (6 Feb 2009)

Good to hear how it is done by the experts Krysstel. For reasons that are difficult to understand the UK is overly attached to masonry construction and, often due to planning constraints, even clad timber frame buildings with a brick skin.  IMHO this is incredibly old fashioned and just adds to the cost. The timber framed buildings I worked on in the 1980’s were built that way because they were cheaper and quicker to erect and as far as I know none have had any problems.

When we do it properly we use much the same method as you describe. We are not so keen on waterproof plasterboard maybe because historically most plasterboards used in UK fell apart as soon as they got damp. Waterproof plasterboards came into the UK from European manufacturers relatively recently.

My self built workshop, temporarily because it is intended to be a “summerhouse” for my wife, is: Concrete pad foundations supporting a timber joist with ply covering deck. Walls are either ex 50 x 75 0r 50 x 100 planed kiln dried timber, inner lining is ply over a polythene vapour barrier. Outer facing is boarding over a water and wind proof breather paper. The frame is filled with glass fibre insulation. Had I known it was going to be more than an occasional use outdoor room I would have used larger studs throughout to allow more insulation thickness.

UK building regulations now require quite high insulation levels and steps to control losses through ventilation or accidental gaps. You probably know that UK government intend that all new buildings will be ”zero carbon” by 2016.

Regards

Graham


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## Jake (6 Feb 2009)

chipchaser":1ao911q8 said:


> One of my heroes is Walter Segal, sadly no longer with us, but a pioneer in self build using a system of framing and standard sized sheet material built off lightweight pad foundations.



I have a feeling we may have had this conversation before, but I share the admiration. I'm also just down the hill from one of the Lewisham developments (I think it is the later one mentioned in the wiki).


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## Krysstel (6 Feb 2009)

The same situation exists in Norway, but in reverse. Baring in mind the climate, no-one can really understand why we don't build with a brick skin instead of wood cladding that has to be painted every 5 years. It always amuses me when I hear relatives in the UK mention they're "painting the house" and they're talking about the window frames + a bit. Here we're talkiing about the house !!

When it comes to the waterproof plasterboard then I agree that it's not long lasting when it gets wet, but if the construction is correct then it's not supposed to get wet, or even damp. The water and wind proof breather paper you mentioned is therefore used more and more now, but you then have to stiffen the construction in some other way such as the diagonal steel bracing used previously - full circle really.

The newest (2006) regulations in Norway now call for minimum 200mm insulation in walls, 250mm in the floors and 300mm in roofs. Particularly in roof construction this has resulted in the same kind (but stronger) of water and wind proof breather paper being used instead of boarding and roofing felt; to reduce the construction height. 

To obtain 200mm wall thickness we don't use 200mm studs. The norm is 150mm filled with glass fibre insulation and then a horizontal internal studwork in 48x48, filled with 50mm insulation. This is far better then a vertical studwork completely filled as it effectlively stops what's known as "cold-bridges" - solid wood right through the wall from outside to inside.
This would be an excellent improvement to your workshop and far better than had you initially built it with larger studs.


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## MikeG. (6 Feb 2009)

This old thread certainly has some life in it!

I am a big fan of timber frame construction, but I use a variation. The description that Krysstel gave of how it is done in Norway is very very similar to what we do here, and certainly not what I would call overkill. 

My method is an inside-out variation on the typical UK technique, in that I have an _*external*_ timber frame and an inner leaf of heavyweight masonry. A 150 mm timber frame with a 50 cavity to the masonry gives my 200mm of insulation zone, with some heavyweight construction within the insulated envelope. Crucially, the external skin is also not broken by the first floor joists, meaning that you can make a decent wind-tight and shrink-resistant job of your timber panel. The studs go the full height of the house in one go (balloon frame).

The roof bears on the timber frame, and the floor is built off the inner skin, blocks, and ideally would be a concrete floor, for more thermal mass.

A bit of cladding or render on battens on the outside, some triple glazed units and a decent whole house ventilation system and bingo............you have a house which will cost a few tens of pounds *a year* to heat. Mine costs about £40 per annum. Incidentally, there are some great breathable sheathing boards now such that you don't need to wrap the building up in a membrane.........and anyway, ply and OSB let so little moisture through that they are a positive nuisance on the outer skin of a timber frame.......That to me is the big weakness in the current design of UK timber frames.

Planning Officers actually have no right whatsoever to be commenting on the form of construction......don't allow them to even have a say on this matter. Building Inspectors similarly, although they of course are required to make sure that whatever you do complies with the regulations. The regulations allow you to do virtually anything that you or your professionals can prove.

Mike[/b]


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## Digit (6 Feb 2009)

And a lot of relevant info in my case. If the weather ever becomes suitable building work that is!

Roy.


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## Benchwayze (6 Feb 2009)

chipchaser":3u3mvy50 said:


> You probably know that UK government intend that all new buildings will be ”zero carbon” by 2016.
> 
> Regards
> 
> Graham



We would be well advised to stop breathing out then? 8)


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## skipdiver (6 Feb 2009)

Been at home today helping my mate to finish digging the footings which are now dug out,concreted and passed by BCO.

The extension i am building is a utility and shower room,single height and 2.4mts x 4.8 mts external size.The footings are nearly 3 times deeper than my 70 yr old double story house,which hasn't moved 1mm as far as i can see.Everything is now overkill and an a*** covering exercise.

This got me to thinking why my footings had to be a metre deep when clearly it isn't needed in this case and why the decision cannot be left to experienced guys like myself and my bricky mate to decide such things.After all,plumbers and electricians are allowed to self certify,so why not joiners and builders?Could we not join a body such as the plumbers and sparks and take the responsibility upon ourselves for stuctural work.Just a thought.

As for my extension,it is now decision time.My mate is coming monday to start building it,so do i just let him brick up to damp course and go for the timber option or do i just let him build it and forget all the hassle?

I didn't have time to discuss options with the BCO today as the concrete was arriving at 2 (they finish at 3) and we only had an hour left to get the last bit dug out in preperation when the inspector turned up.He was supposed to arrive at 12 with the option of us cancelling our slot for concrete if there were any problems,so a bit rushed for time.

If i do decide to go for the timber option(which is very appealing due to massively reduced material and labour costs) then is there anything i need to do at the initial build stage,as in putting some kind of fixing system into the brickwork? Bedding in some straps or threaded bar or something similar to anchor it down i would think is a must but not sure how it's done.Do i go for timber floor as well or concrete?Lots of decisions for the build process.

The other thing i have to think about is will i be required to provide drawings and calcs before i can do anything? All this will add to the timescale and my house is a building site at the moment due to re-modelling inside going on at the same time.I want to get on asap 'cos living like this is no fun.It's tempting to just let my mate build it in blockwork,go to work and forget the hassle.

I ended up building my workshop from blocks because it was "the easy option" at the time and am now regretting that decision.


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## dickm (6 Feb 2009)

Think I've already posted in this thread, living in an all timber (Swedish kit-built) bungalow. Strongly recommend going the timber route, for speed and insulation. Total heat demand of our (3/4 bed) place is about 4kW. 
Not sure about fixing down - can look at the plans if it helps.


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## Digit (6 Feb 2009)

My place, all timber, is free standing, or at least I've not found any fixings.

Roy.


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## MikeG. (6 Feb 2009)

Holding down: all soft-wood timber frames will be held down one way or another. There are specially made clips available, but the easiest DIY method is to build straps in under the brickwork of the plinth and fold them over the plate.....they are usually at 1200 to 2000 centres and adjacent to openings.

The other way is to cast threaded rod into the footings, and drill holes through the plate in the appropriate place.......but this is really difficult to get right.

As for drawings and calcs.......I would say yes, wouldn't I!!! In practice, though, if this is a single storey non-complex extension, then you are going to be using 4x2's at 400 centres with a sheathing board, doubled-up top-plate, and cripple studs to all openings supporting sw lintels, and your building inspector may not require either drawings or calcs.

Mike


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## Gavin-T (7 Feb 2009)

Im sure big rawl bolts would be suitable for fixing the timber to the existing house and to the floor? Or even use the threaded bar method but chem fix them in? Im sure some m14 threaded bar sunk a foot into the ground and chem fixed in would be more than enough!

Gavin.


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## MikeG. (7 Feb 2009)

Gavin,

your second idea is a good one..........the first is a no-no!

Rawl bolts work by expansion, and with fresh concrete can easily be enough to cause a failure (ie the edge can crack and break off). The danger with the chemical anchor route is that a big hole being hammer-drilled reasonably close to the edge of the slab can also cause structural failure.

Mike


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## Gavin-T (7 Feb 2009)

Im not saying to do it while the concrete is still green  

Left a few weeks with the current weather i would be pretty sure that the concrete would take whatever you threw at it. It did while i was doing it at my previous job.

Gavin.


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## skipdiver (7 Feb 2009)

Thanks for all the input guys.The frames will be anchored to brickwork/blockwork so i think bedding in some galvanised straps under the final course of blocks will be adequate.Drilling through would mean peircing the D.P.C.

The building method you described Mike was exactly what i had in mind.The only opening will be a door leading to the garden as the long side looks straight at a fence,so it will be very strong when boarded to stop racking.The only thing i can think of to stop me is wether the Bco thinks it is strong enough to bear the load of the roof without me producing documentation to say so.I know it is strong enough but they usually require you to prove it and structural calcs aint cheap.

BTW.Does anyone know of a site online anywhere that has drawings or info on any of this stuff.There are plenty of house package companies but need some fine detail about fixing methods and particularly products that can be attached to timber and rendered over.


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## MikeG. (7 Feb 2009)

They won't be worried about the load of the roof on such a small extension!! Ideally, the rafters will line through with the studs, but there is usually good reasons why this doesn't happen, so double up the top plate. 

If you are going to use straps build into the masonry, build them in as low down as possible.......I don't think that just under the top course is enough. If you can manage to work around them without poking your eyes out, build them in from slab level. Locate them such that they dont fall on mortar joints, because you will have to screw them to the inner face of the blockwork.

Mike


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## Digit (7 Feb 2009)

Mike! I have to ask. Why the Dung beatle? :lol: 

Roy.


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## skipdiver (7 Feb 2009)

The rafters will line up with the studs.It will be a hipped roof at the same centres as the walls,so not a problem lining them up.I take your point about the straps but am not sure what you mean about slab level.At the moment i have 825mm brickwork from the footings to make up to damp course(4 footing blocks and 5 bricks) and the floor is going to be dug out to a depth of 325 mm,150 hardcore,75 mm kingspan and 100mm concrete which will finish at damp course level.Do you have a different method in mind?The slab being lower and made up with a floating floor or joists perhaps.

So many things to think about.

Off to the footy now to focus on something else for a couple of hours.


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## MikeG. (7 Feb 2009)

Digit":3tyh4lc3 said:


> Mike! I have to ask. Why the Dung beatle? :lol:
> Roy.



Don't you ever get the feeling, Roy, that you are pushing a pile of poo up a hill backwards?

Mike


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## MikeG. (7 Feb 2009)

Sorry Steve...........my mind was on suspended structural conc slabs.......which is all I seem to have done for the last year or two! Different story with a ground bearing slab like yours............all I would say is get your straps bedded in as low down as possible. 

Mike


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## Digit (7 Feb 2009)

Come to think of it.....

Roy.


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## dickm (7 Feb 2009)

Mike Garnham":p4r643qh said:


> Don't you ever get the feeling, Roy, that you are pushing a pile of poo up a hill backwards?
> 
> Mike



Not since I retired 
(perhaps that just means I'm over the hill?)


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## skipdiver (8 Feb 2009)

Decided to go for the timber option.Just been to see my bricky mate and he is bricking up to damp for me(incorporating metal straps)and putting in the concrete oversite.Then i will take over from there.Will be interesting to see what the BCO says when i do it.My partner says i should just build it,render the outside,plasterboard inside and he will probably be none the wiser.

Could anyone shed any light on construction details? Not sure about breathable membranes.

My build method is going to be 90mm CLS frames inside and out with 11mm OSB board on each.Going to counterbatten the inside for pipes and wires before plasterboarding over.

Outside will be rendered,so i need a product that will take render.Some kind of board or mesh.Anyone got any ideas for that?

Do i need breathable membranes and where do they go?

Any input appreciated.


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## MikeG. (8 Feb 2009)

A nice product for rendering directly onto, which also provides some insulation and is a sheathing as well, is Heraklith........a wood-fibre board which is T&G. Best to lime render, though, then the whole wall is breathable. If you are going to sand/cement render, then battens, building paper and EML is the normal way., but you must vent the batten zone top and bottom. 

I would line the inside of the frame with OSB (Stirling Board), then plasterboard directly over that. It stiffens up the p/b wall, and gives you easy fastening for anything you need to fix to the walls internally, as well as providing the moisure resistance you require without using a vapour barrier. Your BCO may not be familiar with this though...

How are you insulating this? You certainly can't just use mineral wool ("Rockwool", fibreglass) if you only have 90mm to play with.

Mike


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## skipdiver (8 Feb 2009)

Wouldn't three lots of 100mm insulation do the trick?All i am doing is replacing the 2 skins of blockwork with timber,so 100mm in each frame and 100mm in the cavity.

Does the Heraklith replace the external OSB and can it only be rendered with lime mortar? I am pretty sure my mate has never rendered with lime mortar.Is it similar in use to cement based render?


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## MikeG. (8 Feb 2009)

skipdiver":2xtbfpd8 said:


> Wouldn't three lots of 100mm insulation do the trick?All i am doing is replacing the 2 skins of blockwork with timber,so 100mm in each frame and 100mm in the cavity.
> 
> Yep, that is more than fine! Sorry, I hadn't understood what you were doing......my fault.
> 
> ...


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## skipdiver (8 Feb 2009)

Thanks once again Mike,it has all become a lot clearer now and i have something concrete to discuss with BCO.

On the other hand,while laying in the bath i started to think about your earlier post and realised that i don't really need a cavity and two skins(obviously where the confusion arose)and that if i beefed up the timber a bit and used the Heraklith,met the thermal requirements with say Kinspan or similar,that i could possibly get away with one skin and have an increased floor area,which would help as i have had to downsize the extension to keep it away from the sewer and more red tape.

The bricky is due a 8.00 a.m. so need to come up with a plan.If i use one skin option,then the brickwork up to damp will be different.

Damn,wish i'd researched this more before i started to build.


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## skipdiver (26 Apr 2010)

Hi chaps,been away for a while.

Just thought i would let you all know that fate took a hand and i was offered a contract working away from home which i accepted and the extension ended up being a normal brick and block extension which a few of my mates built for me.Even the joinery was done by someone else as i was away earning the money to pay for it and all the other internal works on my house.

Thanks to everyone who replied to my original enquiries,especially those who sent me some drawings and i hope to put the knowledge i gained from it to good use on my next project.

My house is now finished and i am getting itchy feet,so i will probably be using some of the techniques in the near future.

Nice to be back.


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## skipdiver (13 Oct 2012)

.....................................and four years on from my original post, the itchy feet i mentioned have started me on another venture...............................

Been busy working my plums off for the last couple of years and preparing for my semi retirement phase, hence i've not been posting here and forgot what a great site this is.

So i am currently doing a full house renovation with my bricky mate for a mutual friend who has recently divorced and downsized to a 3 bed terrace. His ex did the same at the opposite end of town and we got the renovation contract on that as well, so their divorce has been lucrative for us. 8) 

Anyway, on to my point. Whilst doing this latest renovation, a house came up for sale across the road and i went to have a look see, put in an offer, which was accepted and am now downsizing myself, having sold my house to my next door neighbour, who told me over a beefburger at a summer barbie that she always loved my house and would like to buy it if i ever sold. So i put her to the test and she was good to her word. I expect to be moving within the next fortnight.

They say what goes around comes around and i am now in the same position i was 4 years ago, namely having to build a workshop and an extension on the new property. The workshop is pressing as i have agreed with my neighbour that i can leave mine intact 'til i get the new one up and she is happy for me to leave all my stuff behind while i build the new one.

My new house (or should i say old Victorian terrace that needs completely renovating) is fairly unusual in these parts, in that it has a large garden, so plenty of room to get my workshop away from the house and avoid the planners and BCO's. Only problem is that it is quite narrow and to build in timber would mean a metre from the boundary all round which would restrict me in size, so for that reason i'm going for the blockwork option on that and my mate is on standby with his trowel. Will line it with timber and insulation later to make it more comfy and possibly face it with timber cladding a a later date.

We are currently building an extension at my mates house and the BCO just happens to be the same one i had preliminary talks with last time, and like me, he is a joiner by trade, so open to the idea of building a timber extension, and with this in mind, gave me a spec sheet last time he visited site, so looks like i will get to build one after all. 

Just need to wait for the Government now to increase the PDR on house extensions and i'm good to go. They said a months consultation on the 6th September, which is now up, but no word as yet on the new allowances. The BCO has heard nothing at his office yet either.


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