Builder starting small extension, will I regret it

[Oldman]

Right next instalment...

Thursday the roofers were left to felt the whole roof, they had to take felt over where I originally had a cavity wall between the old extension and garage as the builder had removed the capping stones (blue house roof shaped blocks) down to new roof top level.

The spec called for lead flashing all along the house but the builder asked the sub contractor roofer for felt and thats what he got.
So it looks like the builder will be putting lead over the felt sometime soon.

To be continued...

 

[Oldman]

They wanted to come knock out walls and remove windows today but as its a long weekend I put them off doing that till Tuesday, so today was guttering and downpipes, cut and lay more replacement flags and do a second bench up in the manhole.
Now the vent stack and downpipe for the downstairs loo is done its looking very busy in that corner.
Still got a brick surround filled with pea shingle to come where the rainwater drain and sewer pipes are.

You may have noticed the cavity closers are in ready for the new window.

Now the latest problem may be a biggy, but I will continue that in a later post.

 

[Oldman]

We have at present this huge window in the old extension, its 1.5mtr tall by 3.10mtr wide.

(something up with imageshack, not all stored pics are available)

Now originally when the new extension timbers went up the tripple beam was supposed to be tight against the old ext roof, the idea being to bolt the lot together, but the bco said he didnt want to see any joining of old to new.
Also due to the rain drip being that side they had to space the tripple beam away from the old wall plate anyway.

Since then work has gone along with nobody (even me) giving a thought to what happens when the old wide window comes out.
I am guessing as I didnt get to see in there when they had the roof off and the bricky who was up top doesnt recall either, but I think it will be the 7" joists sitting on a 4x3" wall plate over the window and nothing else.

When the window was originally fitted the old crittal came out and the new went in without the need for acrows, although the fitters had them on hand just in case, but I dont think that its a satisfactory way to leave it with a 4x3" wall plate holding that lot up.

Suggestions on a very cheap postcard please, bricking up the proposed opening is not an option.

 

[StevieB]

Given that you have a triple joist on the new roof just next to your window without any support below it, why are you now concerned with removing the window from below the old joist and leaving a joist as the roof support? If it really concerns you, simply add a second joist alongside it like the new triple. So long as you do not join the new to the old (and personally I cannot see a problem with that given the new is in a socket in the house wall anyway - not sure what the BCO is upset about) you should be fine. You must have similar joists every 3 feet or so in the old extension anyway and they are supported at either end. Windows are not supposed to act as structural supports, particularly UPVC ones, so the window itself is not holding the roof up anyway.

100% cast iron guarantee is to put in an RSJ when the now internal wall and window come out and have a pillar at each end but that would be a) total overkill and b) leave you with a drop in your ceiling to hide the RSJ internally.

To be totally honest, apart from the DPC issue I cannot see a huge amount to worry about on this build - sorry!

Steve.

 

[Dibs-h]

Didn't you go with one of the newer generation of torch on roof coverings?

Noggins - on 7" joists I did 2 lots of solid strutting evenly spaced - proabbly slightly overkill as the requirement was 1 lot of herringbone strutting in the middle.

Since you don't have access to the top side - I'd be inclined to do solid strutting. I used 4" screws "toe-screwed" if you know what I mean.

If you want to know the exact spacing - it's in one of the Building Reg documents - will have to look it up for you.

Here you go - very useful.

http://www.luton.gov.uk/Media%20Library ... floors.pdf

Although for floors - can't see it not being useful in your case,

 

[Oldman]

Steve, I think you dont quite understand what I have over the window. I guess you assumed all the old joists run from house wall outwards, but no they run the same way as the new ones do parallel to the existing house.
As far as I can see there is a 4x3" wall plate running the whole width over the window from house side to the other end and all the old roof 7" joists are just resting on that.
Almost a copy of the new build outside wall where all the joists there rest on the new wall plate, so if the window comes out all that will be holding all the joists in place will be a 4x3" timber which I wouldnt call a joist.

So yes it does look like I am going to be needing an rsj.

Dibs, thanks for the useful link, toe screwed they will be. As to the roof covering, I admit to not wanting to test out a new system when the old covering had lasted 30 odd years without leaking. If this does anywhere close to that I wont be around any more to worry about it.

 

[StevieB]

Ah, got you. I did indeed think they came out from the house. I still think you can put a joist from the house wall out down the length of the 4x3 wall plate. If you put it on the outside and make it taller (top to bottom) than the wall plate you can also screw through it and into the end of the old rafters. Akin to an edge on a shelf to stiffen the shelf and stop it sagging.

Still think an RSJ is overkill for that roof to be honest. If it wasn't for the BCO I would say go through the new triple and into the old, so that the new triple acts as a midline joist supporting new roof one side and old roof the other. Did he say why you couldnt join the two? Rather than an RSJ which would need pillars, can you get a 4" square box section in there in place of the wall plate (or as well as on the inside?) In this way it will not protrude below the ceiling and you can plasterboard over the two flush to hide it all.

Steve.

 

[RogerS]

..... not sure what the BCO is upset about) .....

Steve.

It never ceases to amaze me that they all seem to have their pet foibles and interpretations of what, on the face of it, is written down in black and white in the regs!

 

[Oldman]

Steve, thought so :wink:

I am going to strip off a covering of 3mm ply which is hiding the wall plate and joist ends and I will take some pics so its clear what I have at present.
The bco didnt want the 2 buildings joined as he was unsure of the original foundations, he didnt want the old extension moving and damaging the new. At least thats the word from the builder.
Seems pointless as the new walls are tied to the old ones both sides anyway.
The existing extension had planning permission in 1973 ish and is still standing so if it was going to fall over I would have thought it would have done so by now.

 

[studders]

The existing extension had planning permission in 1973 ish and is still standing so if it was going to fall over I would have through it would have done so by now.

Ooooh I wouldn't be too sure about that, buildings are strange, unpredictable beasts, turn ya back just for a second and over they go. :lol:
Can't the 4x3 be 'beefed up'? Seems more sensible than an RSJ.

 

[Oldman]

Remember a few posts back when the builders stripped the old roof covering and timbers they said that the roof not only had firings to shute the water to the direction of the now new ext but also the joists were set lower in the middle too.
Well I just found out why the roof dips in the middle, its the strain of all that weight sitting on an unsupported 4x3" wall plate.
It drops by almost 1" in the center of the 3.10mtr span over the window frame. I have no idea if it was always like that or if thats the reason the original builder put a pair of 1.55mtr steel crittal windows in there bolted together?

I dont think I can now jack the roof joists and wall plate level again as this would no doubt damage the new felting, not sure what the effect would be on the directions the water would want to flow either so it looks like any new supports would need to be bolted through the existing 4x3" in its present bowed state.

What I really dont understand is why when they had the roof covering all stripped back to the joists and firings and were up there with spirit levels moaning about the roof changing direction and having lower joists in the middle it didnt set off alarm bells, I assumed from their discription that the middle of span joists had either been trimmed down in size or set into the wall plate to gain this strange mid span dip.
I would have thought as builders they would have come across this sort of thing before and would realise right away that something was fundmentally wrong.

Here are a couple of pics showing the bow clearly now that I have removed the ply facia that was behind the original guttering and taken the top trim off the upvc window frame.

Here from the old extension side nothing shows, the little plaster damage was when the upvc window was installed.
It gets tricky if I were considering putting a new support beam across on the inside of the room resting on the 2 end pillars as this would involve lots of shims to get the new beam to support each joist in its present bowed position

I am guessing here but maybe if the cut in the house wall was made wider to get another new joist say 7 or 8" x 2 1/2" set in and the padstone concrete block the other end was shaped to take it, I could bolt through the old 4 x 3" wall plate into it leaving the wall plate in its present bowed state?

 

[trousers]

Oldman

Been away a week so just catching up on this thread.

My advice to you (as a builder) is to STOP now and take stock of where you are at.
Sorry to sound harsh but as I see it right now you are going from one unresolved issue to another, quickly, and are hoping some people on an internet forum are going to help you see the thing through. If you feel under pressure from the builder to keep pressing on, resist and tell him you want time to sort out some issues before any more work is done.

The latest issue with the existing roof support is a tricky one because I suspect that your BCO will say that it does not impinge on his jurisdiction over the new extension (they cannot impose regs on existing structures). In other words, he may later issue a completion certificate for the new works, but he won't be interested if the existing extension falls down.

So who specified the structural details (any details :roll: ) for the new extension? Architect, builder, structural engineer, or you? Perhaps the first port of call should be that specifier. However, if it was you or the builder I would be very cautious that you don't make the situation worse. A lot of the things that are happening now are either because there is no spec for the builder to follow, or more likely he has not taken much notice of what he might be up against when it comes to doing the job = cheap price = you pay to get over his problems later on over and above the agreed price.

And what about all the other building details that have now been covered up? Some of it is just down to poor detailing, but the wall insulation issue is fundamental. Did the cavity wall insulation get carried up so that it was continuous with the roof insulation (ie no cold bridging)?

I would be inclined to sort all outstanding details now before you get anywhere near internal finishes, otherwise when the BCO refuses to sign the project off/the builder stings you for extras the **** will really start to fly.

 

[Oldman]

Hi Trousers, this project was set up as a fixed price job, he wasnt the cheapest builder to quote but I got feedback from satisfied customers with this one, its was spec'd as shell only (no plasterboard even) and the specifications of work I drew up was detailed from quotes I had from others.
I do think the job has probably cost him more than he bargained for and now just wants to finish as quickly and cheaply as possible.

As to the wall insulation, the outside wall without a window in has now been filled with insulation to plate level and has 90mm celotex in between the joists on the outer skin, I intend to fill the void to the inner wall with more insulation before the ceiling boards go on.
The wall with the window has certainly got insulation to lintel height and above that is doubtfully completely filled, what did go in after my complaint is packed in too hard so wont act as insulation very well. Rather than argue I will remove 3 blocks under the wall plate after he finishes and reinsulate that top area properly, then replace the blocks.

The need for vertical dpc's on the joining walls was something I didnt know about until well after the walls started to go up so really dont think there was anything I could do to change that, I will use Thompsons waterproofer on the exisiting outer walls near the joins in the hope that this may counter any problems.

Some reasonable news re the bowed wall plate above the 3.1mtr window, I stripped off all the window finishers today and found the window frame sits around 1" lower than the wall plate and the fitter had screwed up into the wall plate with no packing pieces in place so had jacked the wall plate down to meet the frame! The frame had also gone up some in the middle but once I got the screws out the frame dropped and the wall plate recovered some.
So now I am not so worried about it all falling around my ears when the window comes out.
I will still put the extra joist across as I suggested earlier and bolt it through the plate to get it good and strong. I also realise that the bco wont be interested in what I do to fix this as long as it doesnt get attached to the new build roof joists.

Things like the roof flashing in lead was on my detailed spec so he will be doing that before he finishes, the noggins and retaining straps also.
Much of the work is now complete with just the 2 windows to come out, walls (already cut) to be taken down and the new window to be fitted.
The final screed of floor to existing heights (around 40mm) may be a problem with the new dpm being cut to existing concrete level on the old house sides, but when I mentioned it to the bco he didnt think it would be a problem for the builder to correct.
Lastly before he gets paid I would like to try and get the bco to do a drains test and sign that off as well as the other items the builder has done.

Anything done after that point is down to me, I am semi retired and intend to work at my own pace as and when I have the spare money so the job may well take a while ;-)

My thanks to all who have contributed to this thread, I have learned a lot since this started and im sure others reading it are now better informed too =D>

 

[BigShot]

Trousers...
Sounds like some sound advice there.

It never ceases to amaze me that they all seem to have their pet foibles and interpretations of what, on the face of it, is written down in black and white in the regs!

With you there Roger.
We're partnered with a BCO in one of the local authorities (there's a few round here) and we go through him no matter what council the job site comes under.

Even if we had a job on in London (unlikely) we'd use our local (Bury) lad.

Fact is, he's flippin' marvelous. Very helpful, friendly, good with regs and very open to finding the best solution when something tricky rears its head.

Could be worth using something like that if it's an issue you often face. They set up the scheme after local authorities started losing loads of work to private inspectors.

Once you're partnered you can put any job you get through that one officer (but can use the normal avenues whenever you prefer) and what they say about a job goes no matter if it's in their area or not, basically.

 

[RogerS]

That sounds like a cracking scheme, Big Shot. My guys seem to go the other way and not encourage the same person on the same job even. However, they are helpful and pragmatic even though they 'try it on' with their pet foibles.

 

[trousers]

Oldaman

You wrote

...."and the specifications of work I drew up was detailed from quotes I had from others. "

And therein lies the issue that arises with alot of small building works eg extensions of this size.

The customer in these situations doesn't think the project size warrants the cost of architect or structural design and supervision, and to save money relies on their own expertise and/or that of the builder to come up with a spec. Trouble is, any two or ten builders will have their idea of how the project should be done. Leave them to quote for "a shell" and you will get (wildly) different quotes. The customer then sees a cheap one, accepts it, and then expects the BCO to iron out the mistakes and shortcuts as it goes along.

It seems that you distilled your spec from the various builders' initial descriptions of what they intended to build for the price they included. Did you then get them to requote to your spec? If so and you accepted a fixed price quote against that spec then it means 2 things.
1. You are the project manager and are responsible for ensuring that each detail is done to your spec
2. If anything arises as a variation to that spec, then you need the builder to quote for the price variation and agree it before you carry on.

So did you specify the horizontal and vertical DPC detailing, the amount of slope on the roof, chippings or reflective paint finish, etc etc? If not then you are in the hands of the builders idea of how it should be done.

In a worst case scenario, the builder will rely on the absence of a spec, and the customers ignorance of building details, to cut more corners than a getaway driver so the job is finished asap. Customer pays in full, BCO hasn't been on site once in entire project and refuses to issue completion certificate, and builder doesn't answer phone when he's contacted.

Show some builders a detailed (last nut and bolt) spec and they will run away (can't be bothered to price and know they can earn a living cutting corners with hapless customers). However, most clients are not sufficiently clued up to produce their own spec and manage it. This is when they rely on their builder, or bite the bullet and pay for the spec/management.

Not a rant this, honestly :lol: And nothing personal to you Oldman. It's easy to see why the building trade has a generally poor reputation, resulting in TV progs and horror stories in the press. A lot of it is about trust really. Just like voting in your local MP to parliament and then finding out he's on the take on a much bigger scale than your builder ever was :shock:

[/quote]

 

[BigShot]

RogerS
I'll see if I can find the info about the partnership scheme.

If you've got a good one in one of your local authorities it could be well worth going through them.

That said (and this is the one part I'm not 100% on) it could be that the partnership is only for the plan inspection. I can't see why the site inspections wouldn't be the same guy (where it's in his area) as that's one of the draws of using a private inspector, but it could be that it can be different.

In any case though, I imagine you'd have no trouble holding the other inspectors to the approved plans if they try to have their own way with the regs.

I'll have a look and get back to you on that.

 

[Oldman]

Well its pretty much done now, the windows and walls have been removed, the ends of the old cavities bricked up, the house covered in a layer of dust..

I put a prop in for when the builders went on the new roof to fit the lead flashing and finish off the drainpipes and such.

The old extension was built on a concrete raft, here is the wall base back to original dpc

Once they cleared past that to the raft they stopped so they could treat the concrete.

They poured black bitumastic paint from new concrete up the side of the raft and across the top.

Then did the same at the point where the old exisiting kitchen outside wall used to be.

The guy who does the screeding is coming tomorrow, he will screed to a level the same as the existing old kitchen and old extension floors but will leave an area that is I am told too thin to screed, like above the raft. I am to use a self leveling compound in those two areas later. At least thats their plan, hope it works out.

The noggins went in, nail gunned and begrudgingly pee'd.

Last view from the dining room with the old kitchen back end just visible.

 

[Oldman]

The BCO has been and looked, he's asked the builder to fit resraint straps and to nail the metal joist hangers through every available hole rather than just a few.
He was happy with the damp proofing paint.
He also visually checked the drains, but said until the bathroom work and new kitchen are complete he cant oversee a drains test so that will have to wait some time now.

The screeder has been and done his bit too, near 2 ton of sand in there, I think the builder could maybe have gone for a bit more concrete or type 1.

I need to wait a few days now before walking on it, then I can use some leveling compound to finish off the edges.

The builder will be back next week to do the snags, then thats him done.

 

[BigShot]

I dunno why so many still try to get away with only nailing a few holes on hangers. It's not like BCOs ever don't ask for them all to be done.