Any Architects/Architect Technicians in the house? Advice needed…….

Hi All

Overview- recent plans to have extension have hit a wall (sorry for the pun) due to extra requirements needed from Building Control for deeper ++ foundations, increasing costs by another min 9k!! We simply cant afford this.

Architectural Tech acting as our agent drew up the plans and liaised with Structural Eng (structural Eng did not visit site, Arc Tech did), Building Control issued warrant to proceed based on submitted documents from both.

The problem has arisen from the raised patio out the side, where the extension was planned, is ‘made up ground’ and sits between 40-60cm above the road level, with the outer side of the propsed extension within 80cm of this drop to the pavement/road level. This drop lies within our property and within the boundary fence. This was not detailed in the submission.

The Arc. Tech. is claiming that it was not in his remit to perform a sub soil inspection of the ground out the side, but the reason we employed him was to deal with this sort of thing so that we could cost it out?

As it stands the builders called the Council Building control officer out on Day 2 of the job, and he said work could not continue till new Structural plans were drawn up. Therefore we had costs from builder downtime and other costs (skips/equipment hire/mini digger etc) unable to be used until revisions were made.

In short, we cannot afford this extra amount, have lost money on the builders wasted time etc, they have now moved on to another job. We are left paying back loan for extension we cannot now afford to do.

Any advice?

It is not the Architect’s fault. If anything, it is the Structural Engineer’s fault, but I am sure they will have caveats on their drawings. However, in every building project you should always allow a contingency sum of money (we usually work on 5% of the overall building cost) to cover “unforeseen” issues such as this.

By the way, this is a very common problem and is something that doesn’t usually become apparent until work is underway, hence the contingency sum.

I am very surprised by it costing an extra £9k: I’ve just finished a 350m2 extension where exactly the same thing happened, but in this case is was because of proximity to trees. I think it added a couple of thousand.

Edit: If I were you I’d call in another builder to cost the job, together with the new foundation information. I know you have lost money on abortive costs to the current builder but at least you will get things moving again.

The other thing you can do is contact a local Quantity Surveyor to cost the extra for you and negotiate with your current builder, armed with the QS assessment. It sounds like the builder has been given a better offer and is exaggerating the increase to you as he can make more elsewhere.

I take your point, but it should not really be a ‘common’ problem for a small domestic project!
Also, the Architect was to act as our agent and liase with the structural eng.

I take your point, but it should not really be a ‘common’ problem for a small domestic project!

A) It can be a problem on ANY project.
B) This is why I said that £9k sounds a hell of a lot. I’d get it re-priced. It sounds like the builder is having a laugh.

EDIT: Even if I was doing a small loft conversion, I’d still allow for a contingency sum. There are always “unforeseen” issues.

It’s down to the structural engineer to be familiar with the ground conditions when designing foundations. If he needed to he could have asked you to commission a soil report. I would be checking if I can go after his PI insurance.

Oh, and £9k for deeper foundations on a house extension!?

Structural engineer should have dug a trial hole, but I don’t think you’d get much joy pursuing that.

Does sound like the builder is taking the p1ss though – we’ve just built an smallish extension that required 3m deep foundations down one side, and 2m deep down the other due to complex (and tedious) drain issues. The foundations are basic trench fill and the total groundwork cost was ~8K which although a lot, makes me wonder where the extra 9K is coming from.

The Architect isn’t an architect though if a technician. It’s a risk of doing this kind of thing but as others have suggested, try to make it work and get around it – deeper founds can’t be 9K?

Has the Structural Engineer now advised of what needs to be specified, hence the £9k? SE at fault unless they advised/stated a proviso for additional surveys to be undertaken or relied on information from the Architectural tech (which they really shouldn’t).

If the Arch Tec was your agent, what did he ask the Structural Engineer to do? If he just said “here’s the layout, what size are the roof beams?” then it’s tricky. The Structural Engineer should have asked about the whole scope, but if he did that and the Arch Tec (as his client) told him not to worry about the foundations, he’s in a difficult position. If, on the other hand the Engineer did design the foundations, then he should certainly have visited the site and he’s at fault.

I was assuming the Arch Tec just asked the SE for ‘above ground stuff. If the SE worked on foundations without a site inspection, then that’s a different kettle of herring.

SE relied on information from AT. AT drew ground level incorrectly on Proposed plans to Building Control.

no site inspection first asked for. I had to request this from SE to come out at my cost for revised foundation spec and additional costing for the foundations (the extra 9k)

…..and did the AT deal with tendering for the work or did you source the builder?

Hmmmm…. As it’s an architectural technician, I’ll assume they won’t have PII.
I think you’ll have to have a difficult conversation – you can always contact them andtell them that they’ll need to give notice to their PII of an impending claim and see what happens.

Has anyone actually said how far you gotta go down now? That’s brass tacks right there and I could give you an extra over in minutes.

I think you’ll have to have a difficult conversation – you can always contact them andtell them that they’ll need to give notice to their PII of an impending claim and see what happens.

But why should the AT pay for it? If it had been picked up at the beginning, you would still have had to pay for the deeper foundations. You can’t get them for free just because they have been picked up a bit later in the project.

Who employed the SE? I will always ask a SE to allow for a site visit, regardless of the size of project.

Anyway, £9k is ridiculous. Ask for another opinion (preferable a QS, followed by another builder) and tell your ex/current builder to jog on.

Yes, but if they’d got the ground levels correct to begin with then the client gets to SE what the cost will be before beginning work. When you find out too late that they’re wrong then the client has committed monies to the build that they haven’t accounted for which they mightn’t have done if they’d known about earlier.

Aye – dig in and keep going (no pun intended). You’ll get it sorted for less. If you want an all eventualities/risks covered approach then you pay more upfront. Look to save money on finishes/internal stuff if needs be, which can be saved for later.
I’d be withholding paying the AT as well if not too late – if they have made the error you suggest, then they’ve failed you. Too often these fellas undercut architects fees and do a lesser job.

No good structural engineer will commit to “this is your depth” scenarios. At current job we have a coal seam in part of the works. Trial hole position is a guessing game, I think Im yet to meet an engineer who’s requested trial holes for a poxy extension. Getting out of the ground is always a grey area cost wise and from vast experience also depends on what mood the inspector is in!

Sheffield uni built on a coal seam and the pressure ignited it……….which ended up costing someone a Bob or three I believe.

We always state on our drawings “foundation depths to be agreed with Local Authority” anyway. The SE will also say the same. As wrightyson says, it’s the one area that is very difficult to guarantee. Even if you dig trial holes, it’s no confirmation that the depth will be same everywhere.

I also agree with box: Get the structure built and then decorate yourself, or wait until you have the money to finish it off.

This early in the project there may be scope for cost savings to compensate such as cheaper roof tiles, wall tiles, sanitaryware, windows, doors, floor finishes etc.

What proportion of the total build cost is the £9k?

^underground fire^ when I first heard the term I laughed. Till I had to remove the “coal” to put concrete in its place 🙄

My advice would be to get on with it. Mikey74 is right but aP also has a valid point if “proven”. You could spend more time and money arguing about it.

1) No S.E will commit to defined foundation sizes without SI reports
2) I wouldn’t expect an SI report to be undertaken for a domestic extension due to the cost.
3) The drop is minimal and can be priced quite quickly.
4) Has any excavation work been undertaken?
5) What is the extra £9k for. Original / proposed scheme?

You have no comeback as you haven’t paid for a professional unfortunately. This is pretty common when people look to pay minimal fees for this type of work. You should have had a contingency of at least 5 percent, but as others have stated you can fashion your costs for the later elements of the bill to counter any of the out of the ground costs. Just be wary that some builders may also use this type of thing as a cash cow or an excuse to delay. They often test just test how much additional work they can squeeze out of a client…good luck and play hard ball with the builder – they will be used to it.

total build cost circa 22k. this is an estimate for the additional works for the deeper foundations etc.

£9K on a £22k build? The builder is definitely having a laugh.

When you put out the tender, did the Builder(s) visit the site and review the plans/location etc? No one say anything?

And how much of the cost is in relationship to actually getting the spoil away – ie mechanical and/or labour? Plus access.

So did you know about the made up ground? When you bought the place didn’t the searches bring it up? Did you tell the AT?

£9k extra for foundations is surely taking the piss, that would buy you around 100 cubic metres of concrete, that’s one very deep hole
(I appreciate there is labour, plant and temporary works costs included in the £9k)

We had to take foundations for our extension on our last house down over 2m along one face due to an adjacent deep level drain, it cost nowhere near £9k

As it stands the builders called the Council Building control officer out on Day 2 of the job

Getting BC involved on day 2 sounds about right – they should have dug out the foundations & be looking for BC approval.

and he said work could not continue till new Structural plans were drawn up.

This is the bit that strikes me as odd: Normally, if BC aren’t happy, it’s just a case of digging deeper until he is, so maybe 1/2 day extra, or something of builders’ time & a few more blocks to build out, but no ‘structural plans’.

It sounds like the BC officer has decided that the extension foundations are acting as a retaining wall, and as such would need to be designed by an engineer, and will require much more extensive excavation than a trench foundation (and a lot more concrete), but £9k sounds like the builder either doesn’t want it, or thinks he has his d*ck up your a*se. I would *guess* about £2k for a structural design & maybe £2k more for excavation, spoil disposal & concrete.

I think you’re clutching at straws trying to nail the architectural technician for this (essentially they just draw things), and any structural engineer worth his salt will be disclaimered to the hilt. You can never be certain about these things until you’ve dug all the holes and BC have decided to give it the nod.

Therefore we had costs from builder downtime and other costs (skips/equipment hire/mini digger etc) unable to be used until revisions were made.

Any good builder will be busy, and will have been able to send his ‘lads’ elsewhere. Skips only cost when you empty them. Mini digger hire is ~£200 a day, and you can get them off hire as soon as you’ve finished with them.

Call bullsh*t.

Mini digger hire is not £200 a day. I can hire a 9t 360 for 350/week.
Figures aside, your main issue now is having open ground, this is not good especially in the scenario of made up ground and the coming rain. You can personally ring up bc and get him back out. You need to nail him to the wall on what he wants/requires. I’d also arrange for an engineer to be there to back you up. What is the actual scenario with the site levels wise? Regardless of whether it’s made up ground is he wanting you to retain the patio with the newly constructed wall, will the patio become the inside of the extension? If so this is no great shakes and will still require a standard trench fill with some starter bars and then say a simply block retaining wall scenario up to damp.

We had an extension built a few years back and having dug 1m foundations Building Control weren’t happy and told us to keep digging!
Turns out our whole estate is made up ground and we had to dig 2.5m foundations! The rest of the house is 1m – cost us a load c£5k as the builder had to shutter the foundations for safety and due to location couldn’t get a digger with a long enough bucket in so had to be done by hand (plus the extra skips).

In the end we had a meeting on site with building control and a structural engineer which was worth while.

Still I’m safe in the knowledge that when the end of the world comes my extension will still be standing there 🙂

thanks for the replies folks! Food for thought…

We had a similar situation with foundations when we did our extension 18 months ago.
Had to go down 2.5m either side of a drain, which ran exactly where we wanted to put our wall.
The builder is having you on – £9k is ridiculous.
Their costs will consist of labour, plant hire, spoil removal and concrete to back-fill the hole.
If you can’t see £9k in that, he’s having you on.

Assuming the Architect and Structural Engineer were both vague on their drawings / specifications as to the depths of the foundations, (as I would expect them to be without the input of a geotechnical engineer), what depth of foundation did the builder assume when he provided you with a quote ?
If the level difference you describe along the side of the house could easily be seen by the builder by simply standing there an looking over the fence when he priced, I would have expected them to have ‘allowed’ an extra over cost for deeper foundations / under-build along that side of the extension, or at the very least brought the issue to your attention when he priced and certainly before they started work.

9k does seem steep, but IF the foundation is required to extend down significantly beneath the level of the adjacent road, a belt and braces approach may be being allowed for during excavation and casting to prevent undermining the highway and services ??

It’s all just a bit vague to be honest.