# insulating shed and cheapest way to clad inside



## mickthetree

Hey all

I'm putting in SWA cable today and a small garage consumer unit and will need to clad over the top of some of the battens to mount it, so thought i'd look at boarding it out fully and putting in some insulation at the same time.

I see that b&q are doing buy one get one free on loft insulation. Would this be a suitable product to use in my shed as insulation between the battens with cladding over?

Also what is the cheapest way to clad the inside of a shed? 12mm OSB?


----------



## OPJ

Yep, I think 11mm OSB is the cheapest way to clad the inside. Plasterboard is also fairly cheap but, it 'falls apart' if you get it wet and won't stand up to any kind of abuse. :wink:


----------



## Boz62

Yep, I used 11mm OSB as the cheapest interior cladding route. If you paint it, it's harder work due to its' roughness, however. I used rockwool batts for wall insulation - the sort usually fitted in brick cavities. They are thinner, for a given insulation level, so take less valuable space and are better sound insulators.

This is my first winter with a usable workshop after all that - well worth it 

Boz


----------



## BigShot

Loft insulation (I assume you mean the thick fibreglass type insulation) relies on the air trapped between the fibres for insulation so if you were planning on compressing it into a smaller space than it naturally takes up you'll reduce its effectiveness.

Keep that in mind when you're planning what to do.

Other solutions are polyurethane boards (kingspan, celotex and the likes), polystyrene boards (jablite) and foil membranes (web dynamics thinsulex, tri-iso and so on).

The foil and board methods aren't the cheapest, but since neither will need compressing to fit into your walls (the foil is about 15mm thick when uncompressed and the poly boards come in thicknesses down to about 15mm which would allow you to find a balance between insulation and space inside the shed) they should provide more effective insulation.

You may need to consider things like vapour barriers and ventilation for the walls. I'm afraid I can't offer as much input on that as I just work to a couple of standard designs (cold roof and warm roof) when designing loft conversions but you should have a look into it and see what's what.


----------



## DeepBlue

I would have loved to use celotex to insulate my shed, but as it's only a hobby workshop I made do with el-cheapo loft insulation and I couldn't be more please with the result.

After I insulated it, I cladded everything with B&Q finest 12mm chipboard which was the cheapest stuff I could find (excluding plasterboard). I remember doing the cladding in the depths of winter, in a tee shirt, with the temperature outside in negative figures and needing to open a window because it was too hot inside, so I guess it must do the trick!


----------



## BigShot

DeepBlue":1y755pgd said:


> I remember doing the cladding in the depths of winter, in a tee shirt, with the temperature outside in negative figures and needing to open a window because it was too hot inside, so I guess it must do the trick!


Forget U-values, E-values and anything else that's designed to confuse people new to insulation - that is, without question, the best indicator of the effect insulation has on warmth.

The ventillation aspect should still be thought of - wouldn't want mold or rot developing in the walls - but as far as warmth that's absolutely all you need to know.


Was your "el-cheapo" loft insulation the fibreglass rolls or a board one? How thick were they and what size a space did you put them into?


----------



## DeepBlue

I think it was this stuff:

http://www.diy.com/diy/jsp/bq/nav.j...refview=search&ts=1259144277655&isSearch=true

100mm fibreglass rolls in 400mm x 75mm spaces. Yes I did squish it in in places, and yes I'm sure it did compromise my U-value, but as far as I'm concerned it didn't make any difference


----------



## BigShot

As expected.
Yea, squashing it will certainly have affected the U-value, but quite right - what does it matter?
If you can work in there in a t-shirt in sub-zero outside temperatures - it works... U-values don't come into it! 

Kinda makes it clear just how mad the insulation regulations for houses are. Foil membranes, for example, are cheaper and easier to fit than anything that meets the official requirements - but they do a perfectly good job. Once things are "warm enough" in the dead of winter - anything else is just overkill!


----------



## LocalOak

I used some cheap kingspan offcuts from Seconds and Co and clad with OSB. To reduce the weight on doors and cieiing I used 6mm ply. Its all pretty rough and ready, just cut the kinspan roughly to shape and wedged it between the battens not worrying too much about tight fit and drafts. I can now work happily in the shop whatever the weather.

Toby


----------



## disco_monkey79

What sort of impact will the rolls of loft-type isulation, or the polystyrene sheets make in terms of sound insulation?

If the answer is "not much", what's the best for both sound AND heat insulation?


----------



## DeepBlue

I think the best answer I can give is "better than nothing". As a very subjective assessment, lots of sound escapes from around the windows and doors, which I need to steal.

I did look in to making it properly sound proof (so I could use my planer thicknesser at 3.00am if it took my fancy ) 8), and it was prohibitively expensive. As I understand it the "proper" way is to build a room within a room with special fixings which damp the vibrations to hold a second skin away from the outside walls. Then you have to clad everything with expensive sound absorbent material, buy special double or triple glazed windows, etc.

You can still hear me making a noise, but I have very tolerant neighbours, and to be fair the noise with everything closed up is no worse than someone mowing the lawn or hoovering. I just stick to working in reasonable hours


----------



## BigShot

The more dense your insulation is, the better it will insulate against sound.

Stud walls in houses usually have 50mm of 10kg/m³ Rockwool - but that's not so much for keeping in the sound of a screaming router (bear in mind that it also has plasterboard and a plaster skim on both sides of the wall too) - maybe that'll help as a starting point though.


----------



## studders

DeepBlue":26xksq0k said:


> lots of sound escapes from around the windows and doors, which I need to steal.



:shock:


----------



## studders

Build Center still have an offer on for 100mm loft insulation @ £4.49 a roll. Search for DIY100.

hth


----------



## DeepBlue

studders":3ur72s6s said:


> DeepBlue":3ur72s6s said:
> 
> 
> 
> lots of sound escapes from around the windows and doors, which I need to steal.
> 
> 
> 
> 
> :shock:
Click to expand...


Doh! Obviously that should have been "seal".

Although, thinking about it if I were to just nick some nice soundproof doors and windows then problem solved!


----------



## mickthetree

blimey, obviously everyone likes to keep warm!

Thanks for all your suggestions. I only have a small 8 x 10 shed but its getting colder so thought I'd look into it.

Cheers studders!! thats a much better price than I had seen elsewhere!!


----------



## MikeG.

BigShot":26dqodha said:


> Kinda makes it clear just how mad the insulation regulations for houses are. Foil membranes, for example, are cheaper and easier to fit than anything that meets the official requirements - but they do a perfectly good job. Once things are "warm enough" in the dead of winter - anything else is just overkill!



No no no!!!!!!!

Granted there is a law of diminishing returns at play with insulation depth (ie the first inch of insulation when you have none at all does an awful lot more for the thermal efficiency of a building than, say an extra inch when you already have 12), but more and more insulation means less and less fuel. End of story.

As per other threads, it is perfectly possible to have houses in the UK which require no heat in the winter, whatsoever, to maintain temperatures at around 20C indoors, but they require levels of insulation (as well as other design features) which are well over the levels you describe as "mad". Please see "my heating has just come on".

Finally, those "thinsulations" you refer to are not as effective as you think. Firstly, they require a 25mm air gap each side of them, so despite their 15mm thickness, they actually take up the same room (65mm min.) that could be fully filled with Kingspan, for instance, which would achieve much higher levels of thermal benefit. Secondly, they are having difficulty proving that they work. Thirdly, in rooves they require additional insulation to reach the min. requirements of Part L of the regs.

Mike


----------



## OldWood

Can I throw in a wobble ball here please - and it may well be that good building principles do not apply to workshops.

One the things to bear in mind with insulation is that (A) it reduces air flow (intentionally of course to act as an insulant, but bear with me) and (B) it has a temperature gradient across it.

Now if you reduce air flow you reduce the ability of the structure to get rid of moisture, and most workshops have thin external walls which may well not be 100% watertight, so you are now jamming in a material against the outer skin which potentially is not going to allow that moisture to dissipate.

The temperature gradient across the insulation is the next problem as the dew point is quite likely to occur within the insulation in winter conditions, which adds more moisture to that possibly seeping through the external cladding. 

Good practice therefore says that there should be a breathing air gap between the insulation and the outer cladding, and that there should be a membrane on the inside of the insulation to prevent warm moist air getting into it from the workshop.

That can be done perfectly effectively and cheaply in a 3" cavity but does require more work. 

OW


----------



## MikeG.

Now, where is that "Mike's guide to shed building" that I keep banging on about?!!!

You are dead right, and that is why I keep on advocating a gap behind the outer cladding. That and a masonry plinth are the difference between a temporary shed and a proper workshop. You may have seen that I always advocate using a sheathing board on the_* inside*_ of the wall. OSB and ply have a high enough resistance to the passage of vapour that they work perfectly acceptably as a vapour barrier, as well as making a good robust lining for a workshop.

The insulation isn't the problem........it is the detailing, as always.

Mike


----------



## OldWood

Mike - I'm interested that you reckon the OSB and ply are adequate moisture barriers - would have save me putting in a membrane. How do they differ from plaster board with paint on it ? Or is that the household situation is so much warmer and potentially damper that a membrane is necessary there?

OW


----------



## MikeG.

Much more effective than painted plasterboard. I don't immediately have the figures to hand but they are so full of glue that they make a very effecticve vapour barrier, and more than adequate for a shed/ workshop.

They can actually be calculated into a house wall scenario, as well.......but here is the big danger of general advice given over the internet........this will require proper calculation and design for every different situation. People should not think that they can just use this willy nilly instead of a vapour barrier.

I have just done a house with a timber framed external wall which had a services zone lined with OSB......and did not require a vapour barrier as a result. This did entail careful design and specification.

Mike


----------



## OldWood

Well there we go then - over-engineered yet again !! And probably under-engineered somewhere else. 

OW


----------



## MikeG.

Sorry ...don't follow. What is over/ under-engineered?

Mike


----------



## OldWood

Workshop has membrane and OSB!!

OW


----------



## ejimj

I would advise against using polystyrene if there are any electrical cables near as the chemicals used in manufacture of the styrene degrade the cable (search online),
Also if using insulation such as rockwool, should any damp get into the insulation it tends to stay damp and can cause timber to rot, I would therefore use polyurethane boards such as Kingspan or celotex -there are a couple of firms online selling seconds (see e bay) I have used these and they are excellent at just over half the normal price.
E Jim Jones


----------



## MikeG.

Whilst you are right Jim, the point about insulation and wall build-ups is to design them so that moisture doesn't get in them in the first place, and that if it does, it can evaporate off naturally.

The cost of the Kingspan-type boards can be prohibitive for a workshop, and mineral wool is a perfectly good insulant. Just make sure that the wall is properly designed.

Mike


----------



## BigShot

Mike Garnham":uxfj8f11 said:


> BigShot":uxfj8f11 said:
> 
> 
> 
> Kinda makes it clear just how mad the insulation regulations for houses are. Foil membranes, for example, are cheaper and easier to fit than anything that meets the official requirements - but they do a perfectly good job. Once things are "warm enough" in the dead of winter - anything else is just overkill!
> 
> 
> 
> 
> No no no!!!!!!!
> 
> Granted there is a law of diminishing returns at play with insulation depth (ie the first inch of insulation when you have none at all does an awful lot more for the thermal efficiency of a building than, say an extra inch when you already have 12), but more and more insulation means less and less fuel. End of story.
Click to expand...

There is a line, yes, but I believe it is drawn in the wrong place. The level of insulation put into loft conversions is, in most situations I deal with, far more than is needed. When you're working with a limited space, like in lofts or in this case sheds for small workshops, the extra thickness of insulation eats right into your usable space... It's not simply a matter of how much fuel is needed, though that's a factor, it also affects the physical size of the rooms in question - something that is all too often overlooked (to the point where people will, and do, have loft conversions done without building regulations approval because authorities are insisting on insulation so thick it makes a tight job impossible).

The point, though, is that foil membranes have been in use all over Europe for 20-odd years (IIRC) and do a perfectly good job of keeping things "warm enough" even up in the alps. I lived in a swiss-style chalet in Chamonix for a while and even when things were sub zero outside we didn't use the heating. The sloping roof (with no ceilings at first floor and no first floor at all in parts) was insulated with multi-foil insulation only.



> Secondly, they are having difficulty proving that they work.


I dunno about that... They are having difficulty proving that they work when tested in a completely unrealistic test. A test which takes no account whatsoever of external conditions. Houses, sheds, workshops, loft conversions and alpine ski lodges are never built in hot boxes. 

_Real world_ tests of Tri-Iso Super 9 have indicated fuel use equivalent to 200mm of fibreglass insulation in similar situations - and Super 10 (double the thickness) only makes things better.



> Thirdly, in rooves they require additional insulation to reach the min. requirements of Part L of the regs.


I acknowledged in an earlier post that the foils don't meet regs alone - though that may be more a regs problem than a product one. See also above comment about inadequate and unrealistic testing.
I'm unconvinced that the min. requirements are entirely sensible. When you've stood in a loft, in the dead of winter, with no heating and comfortable inside temperatures and you KNOW the insulation doesn't meet requirements it says a lot about the requirements. It's only anecdotal, but it makes a difference in the real world.
Roofs are another reason foils are a good idea and at times a better idea than other insulants. In a small workshop and even more so under a sloping roof in a loft conversion, the extra space taken up by foam insulation can have a critical impact on available space inside the room.


All that said, I agree completely that an air-gap is necessary. For warmth squashed in glass seems to do the trick for a shed (going on anecdotal evidence in this thread) but as I said in an earlier post, ventillation (air gaps in non-"warm deck" construction) needed looking into.



(This'll be marked as edited, nothing more than correcting a formatting error)


----------



## CNC Paul

mickthetree":5ymtwlgi said:


> Also what is the cheapest way to clad the inside of a shed? 12mm OSB?



Mick, I just poped into B & Q they have 9mm OSB for £4.98 sheet.


----------



## mickthetree

Excellent Paul! Was that b&q warehouse in watford? Were they 8x4s did you notice?


----------



## CNC Paul

mickthetree":2fzct1or said:


> Excellent Paul! Was that b&q warehouse in watford? Were they 8x4s did you notice?



Yes, Watford ......The ticket said 1200 x 2400, if you need 1220 x 2440 let me know and I will go and measure the sheets.


----------



## kasandrich

I bought the cheap loft insulation from B&Q for my workshop, I have weatherboarding outside, undertile felt under that, and a thin plastic moisture membrane inside lined with 9mm OSB from B&Q. If you buy, I think it was 10 or more sheets you get a discount, I think I paid about £7.5 each.


----------



## mickthetree

excellent. I'll probably pop over there myself tomorrow and have a look. I need some other bits so could get it all delivered.

Not sure what their delivery charges are but I'll find out.

this is turning into a bit of a 'hot' topic....ah hem.


----------

