Architect extension roof design doesn't work with original building. Are they at fault?

[TobiasTertius]

Hi all, 

 

Apologies in advance for a long winded thread. 

 

The architect on our project designed us a two story side extension where the ridge runs at 90deg to the original house. There is an adjoining roof that runs on the same line as the existing house, but will join below it. See attachment. 

 

He told us at the time that it took a bit of designing to get this junction to work but he had solved it. 

 

We have plan, elevation and section drawings featuring this roof. All with figures dimensions. 

 

Now, with the main extension built it turns out that that adjoining roof as designed does not fit with enough clearance to allow for required flashing to existing. After much wrangling and discussion it has had to be lowered by 300mm to fit. 

 

The new door opening has been lowered so the head height is not an issue, but the issue is the glazing which runs on either side of this section. 

 

Those windows were ordered off plan once the extension was started and layout had been done. There is of course tolerance there to allow for site conditions, but no where near 300mm. This has resulted in us having to reorder one of the windows at the cost of £3k (twice price of original due to small order size). The other window we can lower and form a box gully in porch roof to fit it, not ideal but we worked with it.

 

The architects drawings have stated disclaimers: 

 

"All dimensions and level must be checked and verified prior to any ordering, manufacture or construction."

"Figured dimensions must be taken in preference to scaled dimensions. Contractors and suppliers must verify all dimensions on site before commencing any work or production of shop drawings"

 

Question: 

Could the architect be considered at fault here, perhaps due to general negligence? Do we have a claim for the £3k and he can keep the window? 

 

Budgets are tight to get us dry before winter and I really could do with not swallowing this £3k. 

 

 

Many thanks for reading

 

Tobias

 

 

RoofSection.pdf

Edited August 17, 2022 by TobiasTertius
added jpeg

[Thorfun]

our architect designed a window that didn't work. it was floor to ceiling(-ish) overlooking a flat roof but they didn't take into consideration the insulation of the flat roof and so the window was below the level of the deck. in the end we had to build up the level in the wall to be above the roof and order a new window (only about £700 for us as we managed to tag it on to the existing order that hadn't shipped yet). we made a hole in a wall in another part of the house and used the original window there. so it wasn't wasted money for us just an extra expense that we weren't expecting but on the plus side we had another window looking into the woods surrounding us!

 

I, not once, thought to sue or claim for the expense of that window from the architects but I've been told that I'm too nice! I also didn't want to sour our relationship with the architects over that amount of money. I felt it was a small price to pay for a minor inconvenience. obviously, for you it's a lot more money so would be harder to swallow the loss and a much bigger inconvenience!

 

I can't advise whether the architect is at fault but it sounds like their disclaimer covers them. I guess you need to figure out if the legal costs for pursuing the claim will make it worthwhile if you believe you've a chance to win. people make mistakes and sometimes just need to be forgiven and move on.

 

good luck with whatever you decide to do and it's a shame that this happened.

[Carrerahill]

19 minutes ago, TobiasTertius said:

Hi all, 

 

Apologies in advance for a long winded thread. 

 

The architect on our project designed us a two story side extension where the ridge runs at 90deg to the original house. There is an adjoining roof that runs on the same line as the existing house, but will join below it. See attachment. 

 

He told us at the time that it took a bit of designing to get this junction to work but he had solved it. 

 

We have plan, elevation and section drawings featuring this roof. All with figures dimensions. 

 

Now, with the main extension built it turns out that that adjoining roof as designed does not fit with enough clearance to allow for required flashing to existing. After much wrangling and discussion it has had to be lowered by 300mm to fit. 

 

The new door opening has been lowered so the head height is not an issue, but the issue is the glazing which runs on either side of this section. 

 

Those windows were ordered off plan once the extension was started and layout had been done. There is of course tolerance there to allow for site conditions, but no where near 300mm. This has resulted in us having to reorder one of the windows at the cost of £3k (twice price of original due to small order size). The other window we can lower and form a box gully in porch roof to fit it, not ideal but we worked with it.

 

The architects drawings have stated disclaimers: 

 

"All dimensions and level must be checked and verified prior to any ordering, manufacture or construction."

"Figured dimensions must be taken in preference to scaled dimensions. Contractors and suppliers must verify all dimensions on site before commencing any work or production of shop drawings"

 

Question: 

Could the architect be considered at fault here, perhaps due to general negligence? Do we have a claim for the £3k and he can keep the window? 

 

Budgets are tight to get us dry before winter and I really could do with not swallowing this £3k. 

 

 

Many thanks for reading

 

Tobias

 

 

RoofSection.pdf 201.5 kB · 4 downloads

Those notes seem pretty common, we have notes similar on our building services drawings. 

 

Designing something on CAD and then building it in real life often throws up differences, particularly where building extensions and changes exist and site measuring is critical. I would never order things like windows and doors off plan, if I did I would supply frames for brickys and framers to work to to ensure a good fit but even then, that would not save you in this situation.

 

It is not critically clear what went wrong and why this needed to change, if there was an on site deviation brought about by a detail uncovered during the build then I would say the architect is not at fault, if the contractor varied something on site, then it is not the architects fault. The only time you could claim it was his error would be if clearly something was totally missing from the drawing and not considered. Clear up the whys and we might see a reason.

 

Did the architect draw the house then get the structure designed? Perhaps SE came back and had to make something bigger or smaller somewhere to get something to work and this is the knock-on, but was the architect to update drawings? Sometimes they are off the job at that point and the onus is then on whoever manages it to catch the SE changes and then rework it or appoint architect to tweak design.

 

I am going to suggest you cannot claim for the windows, he clearly states site measurements to be used. 

 

You might be able to get him to help you understand why it went wrong, and if he puts his hands up and say looks yes, this happened, then maybe he will knock something off your bill.

 

It is so common for stuff to change on site, and often people just re-design around it, I spend as much as 1/3 of my time on redesign due to site changes beyond our control that I think it is pretty normal now. 

 

 

[Carrerahill]

32 minutes ago, TobiasTertius said:

Now, with the main extension built it turns out that that adjoining roof as designed does not fit with enough clearance to allow for required flashing to existing. After much wrangling and discussion it has had to be lowered by 300mm to fit. 
201.5 kB · 6 downloads

So, to get the flashing in, the roof had to come down 300mm - OK. So when it was all drawn, how did the roof sit in relation to the existing house and appear to work, is that the drawing you attached?

 

Which dimension(s) are not the same on the plan as in real life. If it works on the drawing, but not in real life, then something must be different. Is the extension higher than planned? I so see, more often than not, ground level changes on site that screw things up.

 

In fact, my own extension roof pitch had to change because what was drawn would only work if the ground level had been about 300mm lower than the drawing suggested. It did work on paper, but the ground level was not going to be taken that low or we would have created a low point all around our extension in relation to the rest of the garden/house which we didn't want. 

[markc]

I was trying to work out why the need for 300mm for a flashing? 

[TobiasTertius]

Hi, thanks for your reply. 

 

The new extension is sitting at the right height compared with existing, both at ground and first floor FFL. I guess the issue is that the original house roof was not as high as measured. 

 

Architects drawings contained all SE details as well. So full construction drawings. 

 

I realise that in an ideal world you wouldn't order off plan. But will tight timescales and window prices going up monthly it seemed (ended tup +30% over a year), we wanted to get ahead. Once the footings were in we incorrectly assumed perhaps that site conditions has been considered at that point. 

[Carrerahill]

6 minutes ago, markc said:

I was trying to work out why the need for 300mm for a flashing? 

Looking at that PDF I am assuming that the hips are too high. As you allude to, 300mm is not needed for flashing, 150mm but I have seen 75mm argued. So I can assume that actually the 300mm is because they are minus 150mm at the moment and to create 150mm they need 300mm... 

 

If someone thinks they need 300mm for flashing then, there is another issue here!

[TobiasTertius]

That is a very good point, and perhaps I should have been clearer from the start. There are two issues at play.

 

Actually the flashing allowance was an extra 85mm. There is also inconsistency in the section and elevation drawings. The elevation drawings have window dimensions and have this window figured at 1881 height. The section drawing I included above has no figures, but when scaled gives 1600 height.

 

So the window is too big by 281 mm due to incorrect figured dims, and should be 1600.

This 1600 needed to reduce to 1515 to accommodate roof build up and flashing.   

 

Apologies for not being clearer, I had conflated the two myself. 

Edited August 17, 2022 by TobiasTertius

[joe90]

This does not surprise me, my neighbour had an architect design his extension, when he showed me the plans for my opinion I told him it would not work (again roof height vs junction and doorway), I came up with the solution for him, he told his architect to alter the drawings and he was not going to pay for additional cost for this as it was his mistake in the first place. Most architects drawings have dimensions on them (which should be accurate) but the notes say “do not scale from the drawing to arrive at dimensions missing”.

Edited August 17, 2022 by joe90

[Radian]

Architects have an array of cop out clauses they like to employ. "To be designed by others" is the one that makes me giggle the most. I've got a similar story to the OP but haven't got the emotional energy to write it up. The upshot was an unexpected change of plan and spend of several K. We really shouldn't have let them off the hook (another case of incorrect measurement) but we did. The real kicker was when we got a substantial bill over one year later for a site visit that our builder had arranged with the architect to try and solve the problem (which it didn't). The Truss manufacturer solved it in the end. They were golden.

[Ajn]

1 hour ago, TobiasTertius said:

Those windows were ordered off plan once the extension was started and layout had been done.

Did you order the windows from a schedule supplied for the purpose by the architect? If you did you may have a good case for a claim. If you took the details from the plans then you maybe on your own. The reason I say this is because our architect had a number of services from basic dimensioned drawings for planning to builders/BC drawings and then schedules for windows etc etc. The price for each element went up quite a lot in relation to the level of ownership. Ours was a restoration with extension so needless to say we went with the basic drawings. Many things were uncovered during the build process that would have been wrong on a drawing with information known at the time.

[CharlieKLP]

Yes I am sorry to say that the architect is not at fault and you can’t sue them. 
 

I have always thought it’s stupid to put dimensions on, given they are just general ones for guidance. 
 

sounds like the insulation/flashing is a cock up,  but the ordering of windows is sort of on whoever did that off plan. 

[George]

What survey information was the architect using to design the extension? 

 

Short answer is no, dimensions should have been checked prior to ordering. 

[TobiasTertius]

Thanks all. 

 

I ordered the windows off-plan by supplying what I was told was full construction drawings to the manufacturer. Sizes were confirmed with contractor prior to ordering so they were aware. 

 

I was never offered a window schedule, but I can see the value in having no opening sizes on the plan and having a separate window schedule. That would have resolved the difference in dims on different drawings but would not have resolved the roof issues. I guess the architect would only supply that schedule once they have remeasured part finished build on site, and that would be the difference. 

 

I have windows on site now, so that would have meant an additional 3 month wait for windows, but I guess for piece of mind and to cover cock ups like this that is the 'wait' you have shoulder. Or with hindsight maybe I could have requested a split order to allow for updates to the important windows. 

 

I guess the window will be going on eBay. 

 

Is there a site section for unwanted materials? 

[CharlieKLP]

See if the window manufacturers will take them back too, maybe they can use the bits again and give you a better price.

 

you’re not the first person this has happened to btw, windows always mess up a project. 

[joe90]

Well I gave the brickies rough dimensions for the windows cus I wanted full bricks or half bricks only, (yes I am OCD) no slivers!!!, then I ordered the windows to match the openings which were made locally and lead time not too bad 👍

[Faz]

6 hours ago, TobiasTertius said:

Hi, thanks for your reply. 

 

The new extension is sitting at the right height compared with existing, both at ground and first floor FFL. I guess the issue is that the original house roof was not as high as measured. 

 

Architects drawings contained all SE details as well. So full construction drawings. 

 

I realise that in an ideal world you wouldn't order off plan. But will tight timescales and window prices going up monthly it seemed (ended tup +30% over a year), we wanted to get ahead. Once the footings were in we incorrectly assumed perhaps that site conditions has been considered at that point. 

 

As you have found, commercial sites don't call off windows until the opes have been built unless using formers.  You can get the package contracted locking into the current price with final call-off subject to site measure. You may have seen lots of new builds waiting for windows as a result as the lead times have gone from 2 weeks to 10. But at least they will fit when they arrive!

[CharlieKLP]

I’ve done it off plan on new build timber frames, so it is possible as long as everything is certain. Tobias wasn’t to know that though, I do think if he’d spoken to the architect for a door schedule it would have come up. 
 

>Sizes were confirmed with contractor

 

now that might be a case… so your builder confirmed the sizes?

[Temp]

We had good architect for our new build and a great builder. Builder told me he never builds off plans, he always builds off the last bit he's built 🙂

 

What he meant was he never trusts even himself so allways measures before buying anything. 

[ETC]

7 hours ago, CharlieKLP said:

Yes I am sorry to say that the architect is not at fault and you can’t sue them. 
 

I have always thought it’s stupid to put dimensions on, given they are just general ones for guidance. 
 

sounds like the insulation/flashing is a cock up,  but the ordering of windows is sort of on whoever did that off plan. 

Difficult one - but I don’t necessarily agree with CharlieKLP.

 

No - you should never scale off a drawings for anything and should always use site or figured dimensions.

 

However my personal opinion is that if you were supplied with inaccurate drawings by your architect then he should accept some responsibility for the mistake - irrespective of the drawings being dimensioned or not or any caveats placed on the drawings. Speak to him and tell him how you feel.

 

Am I correct in saying that the section is new works and the gable behind is existing. If this is the case then the solution your architect came up with looks quite contrived. It would have been better to extend the existing roof over the new extension and to forget about flashing - just my opinion.

[CharlieKLP]

I bow to experience! That’s a very good point ETC. Worth trying the angle that the drawings weren’t fit for purpose like you said in the first place. 

[George]

2 hours ago, ETC said:

Difficult one - but I don’t necessarily agree with CharlieKLP.

 

No - you should never scale off a drawings for anything and should always use site or figured dimensions.

 

However my personal opinion is that if you were supplied with inaccurate drawings by your architect then he should accept some responsibility for the mistake - irrespective of the drawings being dimensioned or not or any caveats placed on the drawings. Speak to him and tell him how you feel.

 

Am I correct in saying that the section is new works and the gable behind is existing. If this is the case then the solution your architect came up with looks quite contrived. It would have been better to extend the existing roof over the new extension and to forget about flashing - just my opinion.

 

If the architect was supplied with a full on professional survey then maybe... but if it's just what they could manage with a tape measure and maybe a dumpy level, then all of their drawings is based on ... not rubbish ... but site dimensions will take precedence. 

 

And even with a survey... wouldn't the survey provider not bear responsibility if the design doesn't fit? 

Edited August 17, 2022 by George

[ETC]

10 hours ago, George said:

 

If the architect was supplied with a full on professional survey then maybe... but if it's just what they could manage with a tape measure and maybe a dumpy level, then all of their drawings is based on ... not rubbish ... but site dimensions will take precedence. 

 

And even with a survey... wouldn't the survey provider not bear responsibility if the design doesn't fit? 

Good point - however the onus will be on the architect to check that the information he is supplied with is accurate.

 

I also suspect that the survey was carried out by the architect and not a third party - I could be wrong but for a (small) domestic project like this I would imagine that the survey was carried out in house rather than sub-contracted to a third party. 
 

OP suggests that the elevations and sections did not tie up - amateur mistake.

 

Just my opinion.

[TobiasTertius]

Hi, 

 

Yes the architect did the survey themselves.

 

I do think it is pretty poor that the elevations and sections did not tie. There was other discrepancies in the plan ground vs 1st floor drawings to do with vertical steels appearing in different locations, but that did not have a major impact. Both of these are a sign of sloppy work, perhaps architect running out of budgeted time for his original quote. However, I don't think they warrant a claim in their own right. 

 

From my own use of SketchUp etc, and seeing architects produce 3D models (not for us), I had assumed that all drawings were part of the same model. Clearly not.

 

I will reach out to him and ask him to either redesign the window opening to somehow fit the original window, which won't be possible due to headlight and insulation requirements, or to help us purchase a new window to fit the opening. Will see what he says, but I am pretty sure of what the first response will be. 

 

If this was earlier on in the build I am sure we would have swallowed it into the overall glazing budget. But now we are at the sharp end of the first phase (getting dry) the money is running out, including contingency, so for now we are likely to block the opening for the winter and deal with it next year. 

 

Thanks all for your input. 

 

A triple glazed Velfac V200E 2153x1881 will be going on eBay most probably.