Building Tolerance On Room Size

[Mark Elvin]

My original question was

"What's a std acceptable deviation from the room size shown on a plan against the actual finished size?"

In reality, it won't stop anything going in & won't cause a huge issue to us, it was more of a general question. At no point did I suggest any action against the builder.

 

[noseall]

So, if the builder stuck to the drawing and you ok'd the drawing and you watched it being set out, why are you moaning about sizes now they are about to put the roof on?

Did the builder stick to the drawing that you ok'd?

Did the building suddenly appear over night?

Seems to me like F1 engineers are a bit silly.

 

[Mark Elvin]

So, if the builder stuck to the drawing and you ok'd the drawing and you watched it being set out, why are you moaning about sizes now they are about to put the roof on?

Did the builder stick to the drawing that you ok'd?

Did the building suddenly appear over night?

Seems to me like F1 engineers are a bit silly.

Like I said, some people obviously have too much time on their hands & take pleasure from winding others up.

 

[limerockconstruction]

In reality, it won't stop anything going in & won't cause a huge issue to us

Surely thats the end of this thread then.....but does beg the question why it was started anyway?

Mark, the tolerances you are experiencing are well within the permissible spectrum.

 

[mfarrow]

Mark

Looking at your photos, you have left 1/2 brick between the existing window and the new extension, which is right to give you some space for the sill and you couldn't have got any closer, and you're flush to the existing gable. The builders used standard brick/block and minimum cavity specification which cannot be altered easily. So the width is fine.

As for the depth, I suspect again he's gone for the nearest half brick dimension. OK so perhaps he could have gone one halfbrick more but what did it say on your planning application for distance of new gable from existing?

If you want everything to be just right then you have to check the work every step of the work. This is why I don't employ tradesmen, no offence to any but I'm just too picky and will drive them mad, or I'd take a week writing the spec.

The other problem you have is that anything that a builder receives will have lots of 'definite' dimensions on it somewhere, i.e. 50mm cavity, 900x900 windows, etc. The builder has to assume certain things can be 'about right', because if he built a cavity within 49.50mm and 50.49mm you won't have the extension done this year.

 

[freddiemercurystwin]

Any builder who is given some specified internal dimensions to work to then botches it is a dope, careless or can't read, depending upon how well publicised this specified room size was and how well the existing building was surveyed, if that had a bearing. The bleating on this thread about tolerances, what defines internal measurements and trotting out the BS is usual builders excuses. If some of the forum members on this thread are given specified internal dimensions and end up in error, they must not have the brains to allow for simple building tolerances or stretch or shrink the coursing or whatever. Brain surgery it is not.

 

[RonnyRaygun]

The room INTERNAL size should be 2400x3065 FINISHED

I think that's pretty explicit really, and it looks to me like the builder has built the inner skin of the blockwork to the specified finished size.
I think it's a mistake by the builder and not within any acceptable tolerance.
I think some of the builders here are getting a little precious

 

[jeds]

Standard tolerances aren't made up for fun. They exist because building materials and workmanship aren't millimetre precise and it's not feasible to measure to that degree of accuracy. And most people wouldn't have a clue how to anyway. Even a closed survey with the best EDM equipment allows a certain tolerance. A bloke with an uncalibrated steel tape from B&Q is allowed a bit more.

 

[freddiemercurystwin]

When a minimum finished size is specified it should be adhered to. This threads an embarrassment to the builders on here.

 

[^woody^]

You expect a builder or even plasterer to work to mm accuracy, when no other standard or industry body does?

It's easy to say from behind a CAD program which does lots of nice perfect straight lines

Explain how that plasterer actually goes about achieving a skim surface with no mm deviations at all over the entire length of a wall

 

[freddiemercurystwin]

I would expect that if a minimum finished size is specified then the builder should take steps to ensure that his tolerances achieve that minimum size. If he can only build a wall within a couple of inches of where its supposed to be then he should allow for that and if the room ends up bigger then so be it. At least the minimum is achieved.

A poor tradesman always blames his tools/materials.

 

[noseall]

I have said all through this thread that if the internal finished plaster size was critical then the builder should have strived to achieve it or given his reasons why not.

I have also asked pertinent questions regarding the drawings and setting out which F1 man did not like so he did not answer.

I agree that when setting out you can add or pinch a bit on the perp's and have stated it is more difficult on smaller extensions, simply because there are less perp's to do it with.

It looks as though the builder has read the internal size as block to block and not plaster to plaster. I'm curious as to why this was only spotted when the roof is about to go on and why it was not discussed when the drawings were being studied.

 

[mfarrow]

Exactly, I know I said I don't have many trades in the house but I do client representation at work and if there's something quirky or important in the spec I don't just leave it in there but discuss it at the tender stage and contract award and design reviews and etc.

We have a set of drawings at home for an extension done by previous occupants. If I were to measure up tonight I'm sure I'd find some variation. That's just the way the trade works.

Another example is a friend who did some lighting work for a rich couple who were having a large house and an annex built by separate contractors. Annex contractor "raised concerns" that main house walls weren't quite true/plumb and used tapes and levels to prove it. Even though they were small differences he got main contractor sacked and took on the whole lot himself. I know it's an extreme example but it's what happens if people are misguided on these things.

 

[Mark Elvin]

In reality, it won't stop anything going in & won't cause a huge issue to us

Surely thats the end of this thread then.....but does beg the question why it was started anyway?

Mark, the tolerances you are experiencing are well within the permissible spectrum.

Like I said, if that's the case I'm happy to accept that.

 

[RonnyRaygun]

Mark, the tolerances you are experiencing are well within the permissible spectrum.

Like I said, if that's the case I'm happy to accept that.

I don't agree. It's clear that the builder has built the inner face of the blockwork to the specified FINISHED dimension. It's a clear mistake, and over three metres to be out by 60mm is careless. The drawings were explicit, but the builder measured block to block, and didn't consider the finishes.

Agree though that it should have been checked at a much earlier stage when it could have been corrected.