Cost for increasing house dimensions

theexis

Hi,

prior to commencing our contracted self build we moved the rear wall of the house back 500mm, adding an additional 14sqm to the house (building is 14000mm wide).

Contractor is now quoting almost 30,000 for this change broken down to additional digging/foundations/plastering/concrete in the house and roof (roof addition alone is costing 4000 euro). My own calculations are much lower than this, but I'd like to hear other opinions.

muffler

theexis wrote: »

Hi,

prior to commencing our contracted self build we moved the rear wall of the house back 500mm, adding an additional 14sqm to the house (building is 14000mm wide).

Contractor is now quoting almost 30,000 for this change broken down to additional digging/foundations/plastering/concrete in the house and roof (roof addition alone is costing 4000 euro). My own calculations are much lower than this, but I'd like to hear other opinions.

That would be the equivalent of almost €2150/m2 which is ridiculous. On face value Id say you should be looking at around €1200 - €1400 per sq. metre and I'm assuming that this a fairly standard type build..

Get yourself a QS and for the sake of a few hundred euro he could save you thousands.

BryanF

theexis wrote: »

Hi,

prior to commencing our contracted self build we moved the rear wall of the house back 500mm, adding an additional 14sqm to the house (building is 14000mm wide).

Contractor is now quoting almost 30,000 for this change broken down to additional digging/foundations/plastering/concrete in the house and roof (roof addition alone is costing 4000 euro). My own calculations are much lower than this, but I'd like to hear other opinions.

just to clarify? have you done the work already? ie are you still in control..

I don't suppose you have an architect or QS on board that can argue your case on your behalf.. that is certainly a high figure!

just to add to your worries, you need inform the council of the change to PP.

theexis

Ground works are completed to foundations and finished concrete floor at present, walls are going to start going up soon.

I don't have a QS involved at present - how would that work with a contracted build (I'm not managing the project / using direct labour etc).

SBR

As you have already appointed the Contractor, The QS's role from here would be to manage the building cost from start to finish, this would include costing and agreeing the cost of Variations (if any) as they arise such as adding an extra 14m2 to your property! The QS would also be in a position to recommend the value of works completed by the Contractor on an interim basis ensuring that you don't overpay the Contractor at any one time, and then finally agree the Final Account with the Contractor!

BryanF

theexis wrote: »

Ground works are completed to foundations and finished concrete floor at present, walls are going to start going up soon.

I don't have a QS involved at present - how would that work with a contracted build (I'm not managing the project / using direct labour etc).

so your not managing the project? who is then? have you anyone on your-side (so to speak)?

theexis

BryanF wrote: »

so your not managing the project? who is then? have you anyone on your-side (so to speak)?

Our contractor is managing the project in so far as supplies, trades etc. We have an engineering firm in place to sign off on the stage payments only. We had an architect work on the original planning submission but they are not involved now.

Assuming I hadn't got my current issue for the additions, should I still be employing other professionals?

Carlow52

theexis wrote: »

We have an engineering firm in place to sign off on the stage payments only.

This is the only glimmer of hope here to stop you being screwed.
... and that is assuming they do some onsite calcs as opposed to back of the envelope calc [280k /28 weeks/ this is week 10, already paid 8k so hey presto 2k due this week.]

the builder may be happy to let the the extras ride till the end.

IMO u need to get it sorted pronto as the number is outrageous.

You are in a tricky spot here.

ps who will do the sign off on compliance with planning and regs?

theexis

Carlow52 wrote: »

ps who will do the sign off on compliance with planning and regs?

Sorry my ommision there, eng. firm also engaged to signs off on these and complete the BER.

theexis

For my own sanity do the following look any way accurate (my calculations!) for the materials cost ex VAT of the roof additions?

Additional roof area - 500mm at 35 degree pitch = 610mm = 8.6m2

Thrutone slates 14 per m2 required (thrutone booklet spec) = 120 slates
Felt - 1 roll (75sqm)
Battens - 4m per m2 required (thrutone booklet spec) = 34m battening
Insulation = 7m2 @ 300mm thick

Slates: 1.20ea = €144
Felt roll - solitex = €175
Battens €1 per metre = €34
Insulation €8 sqm = €56

Materials Total: €409

Carlow52

plus rafters/ridge board/soffit/facia/guttering/wallplate/ wall plate ties/

IMO take full cost of house on original size and gross up.

As I said already this issue needs resolving and you need to be considering replacing the builder because if he thinks he can screw u for 30k on this I would hate to see what the extras will look like at the end.

Have you got you engineering guys involved here: I am gravely concerned when I see a calc like this at 409 that you are being seriously penny wise and (1000's of) pound foolish

theexis

Carlow52 wrote: »

Have you got you engineering guys involved here: I am gravely concerned when I see a calc like this at 409 that you are being seriously penny wise and (1000's of) pound foolish

Not yet, I only got a more detailed breakdown of the 30k today - this was just 1 line item that stood out as highly inflated so I wanted to get it straight in my own head (listed as 4200 on their quote, wondered how it could possibly cost that).

Oh, and soffit/facia/guttering is listed separately as an 600 euro...

muffler

theexis wrote: »

Oh, and soffit/facia/guttering is listed separately as an 600 euro...

There wouldnt be any addition here unless you count in the barge if its being done in PVC

BryanF

theexis wrote: »

Our contractor is managing the project in so far as supplies, trades etc. We have an engineering firm in place to sign off on the stage payments only. We had an architect work on the original planning submission but they are not involved now.

Assuming I hadn't got my current issue for the additions, should I still be employing other professionals?

everyone to their own, in an ideal world you would retain an arch or Project Manager to at least help you avoid such issues, why not go to the certifying engineer and ask him to step in on the debate or he may know a QS... (he should be informed anyway as he need to explain alteration to you PP!!)

Casati

Carlow52 wrote: »

plus rafters/ridge board/soffit/facia/guttering/wallplate/ wall plate ties/

IMO take full cost of house on original size and gross up.

As I said already this issue needs resolving and you need to be considering replacing the builder because if he thinks he can screw u for 30k on this I would hate to see what the extras will look like at the end.

Have you got you engineering guys involved here: I am gravely concerned when I see a calc like this at 409 that you are being seriously penny wise and (1000's of) pound foolish

I dont think its fair to gross up the overall build costs- it unlikely the moving the wall will increase the electrical or plumbing fit out for example- the kitchen wont cost any more, and it wont need an extra few steps on the stairs for example! The best approach is to get the builder to detail specifically what additional costs this change is driving, I'd imagine that 50/60 sq m would be more like it

Carlow52

Casati wrote: »

I dont think its fair to gross up the overall build costs- it unlikely the moving the wall will increase the electrical or plumbing fit out for example- the kitchen wont cost any more, and it wont need an extra few steps on the stairs for example! The best approach is to get the builder to detail specifically what additional costs this change is driving, I'd imagine that 50/60 sq m would be more like it

Cannot argue with that, I suppose I should have said that that would give the OP a topside figure, as long as he strips out landscaping:)