Cost of first floor extension

Was wondering if anyone could give an approximate cost for building a 28sq m first floor extension. It's a 4 bed semi with a ground floor extension to the side. Has planning permission to add 2 new bedrooms above this (1 window in each room) and to move the bathroom from the middle to the back of the house as its window is currently on the side of the house, this will require an existing window to be moved a couple of feet. Also a couple of interior walls to be moved a few feet (both non load bearing, just resizing an existing room and killing a teeny room) and the stairs that turns to the right for the last couple of steps will now also turn to the left to get to the doors for the new room. And the roof (pitched/hipped on 3 sides) will need to be extended over the new bit.
Considering buying this house but need a ballpark on the cost to help us decide, really haven't a clue if we're talking €30k or €60k.

Any help appreciated,
Thanks

hi,
I think you need to get a local friendly builder to have a look for you as otherwise you're only guessing- they'll be able to give you a ball park price for moving all the bathroom plumbing and the roof - which i think would be the expensive bits-and of course you can spend anymoney on kitting out bathroom depending on what you want to spend. just watch out for the stairs as they can be tricky to get right with head room if you are changing them- def worth getting a set of drawings done for it and examining them closely if you go ahead- and you'll find vendors will be only too happy to let you bring a builder through if it increases chance of a sale- if fact you can use it to your advantage if price comes in high and use to negotiate your offer price downwards- then go bargain hunting !

thanks choccy - already have the plans drawn up for all of this and pp granted for them, just wanted a ballpark, but it looks like we'll just have to find a builder (or two) to ask. As for finish, basic bathroom will do, not looking for anything flash, and will do all tiling, painting etc. ourselves afterwards.

Make sure you find out whether the foundations on the existing one-storey extension are deep/strong enough to support another floor being lumped on top. If they're not, the costs may escalate...........

f9710145

If you don't involve building professionals at this stage in the proceedings you will tend to experience problems later on.

PRICING

Depending on the level of detail on the plans you may not have enough information to obtain an accurate price.
Worse, you may leave sufficient information "up in the air" to allow the building to claim reasonable extras.

Typically this will allow him to come in with a low initial estimate and go back to you with a half-finished building claiming 50% more - what will you do?
If you fail to specify everything befoer appointment and include things in the tender documents he can say he priced for such and such, which he can get cheaply of course, and what you specify will be regarded as an extra.
This then opens up the whole issue of "equal approved" substitution of materials, which could take several posts to even cover adequately, but it is one of the reasons for producing Tender Drawings and Specification to price from and developing these into working drawings to build from.

DOCUMENTATION

You have got Planning Drawings and these may be inadequate to the task if you are unfortunate in your choice of builder and you have no professionals on board to determine what is acceptable under the contract.
Of course, this assumes you have a contract, which many self builders do not, or they place themselves wholly in the Contractors hands - an unwise move in my opinion.

The RIAI Contract for small works (white form) should be used as currently amended as a minimum, of you could use the Blue of Yellow forms depending on advice received from your building professional.
Make sure you have a professional skilled in building contracts vet and thoroughly read through any other form of contract offered to you - for example by a solicitor acting for the builder.

SURVEY

It is important to fully assess the existing building in terms of structural interventions. Some well-built single storey extensions will be adequate to the task of carrying an additional storey, some won't. Its important to have the original building and the extension assessed by an engineer structurally in conjunction with having it designed by an architect.

DESIGN

The reason is that to achieve the best visual and architectural result often involves raising transfer beams above the level of the ceiling and reducing nibs to nothing in the walls. This concentrates loading and puts both the existing superstructure and foundations under point loads they were never desigend to carry.

Unless your architect and engineer work together to achieve the best possible result, co-ordinate the modifications and additiosn to the structure to achieve the architectural design you may run the risk of unusual levels of settlement and cracking. In a severe case this can lead to problems with drainage and in the worst case actual structural collapse may occur. This is not what you want to occur.

SEQUENCE

It should be obvious from the above, but let me spell it out - all this should be considered, proposed, designed and resolved to your and your professionals' satisfaction before the proposed development is sent anywhere near a builder for pricing.

In particular, you and or your partner or other stakeholders should have finalised the design proper. Reviewing what you have permission for needs to occur before the Tenders are issued, because changing things on site and variations to the contract cost both time and money.

If you fail to sign off on the design before Tender you will remain uncommitted throughout the whole build and this tends to lead to ongoing changes during construction, which in turn multiplies costs hugely.

SUMMARY

Proceed on the basis of Planning Drawings at your own peril. My best advice is to appoint appropriate building professionals to design, specify and certify the work. Otherwise what will happen at handover, at stage payments and finally when you or your successor in title eventually sells the house?

ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon as a defence or support - in and of itself - should legal action be taken.
Competent legal and building professionals should be asked to advise in Real Life with rights to inspect and issue reports on the matters at hand.

Thanks ONQ for the detailed response. The plans we have were drawn up by an architect, they do detail the foundations for both the original house and the existing extension, also there are specifications for types of brickwork, roof tiles, joists, etc. We would be getting a surveyor to assess everything before any puchase was made.
I do plan to either get back on to the architect who drew up the plans or engage a surveryor/engineer to check for compliance during the build. We also do have some changes we would like made to the existing plans and am already talking to the planning dept about whether they can be amended without full reapplication. The reason I was looking for a ballpark figure was simply to see if it was feasible or not to buy and extend. I have been given a guideline by a builder of approx. €1000 per sq metre with another €5-€6k for moving the bathroom, which would suggest that it shouldn't be as much as €60k. €40k with some contingency would be manageable so I think we may go for it. And by that I mean sell our own house, then get the other house surveyed and go from there.

So thanks for all replies

I think you're trying to fool yourself here on the cost.
Listending to you resting your entire strategy on the off-the-cuff word of one builder suggests you may not know what you're about in terms of how you're facing into this
At all times when you are developing you should look like you know what you're doing to your financiers and the one thing that undermines this time and time again is under-providing for the cost of the works.

You should have funding in place for the higher costs - which you may not need - rather than go scrabbling to your financier looking for more money in a panic - it never impresses.
Do not go into this on a shoestring or you will find your back against the wall if you need more money.

Do not go into this based on on builder's off-the cuff comment.
Do not go into this with no contract, no written quotation, no rates, no breakdown, nor any firm price.

You need a competent comment on costs by an architect or a quantity surveyor who has experience of being involved in small works.
You need to agree rates for extras during the tender negotiations and select a contract that is appropriate for the type of works envisaged.

Extras like the replacement of an existing plumbing system in a ceiling where steel beams are about to be recessed can make up a large proportion of the cost of a small job.
OTOH if you were building an entire house from scratch, a change of similar order would not be noticeable and if caught in time, might not affect the price significantly, if at all.

Extensions are no justification for skimping on the appointment of professionals.

On extensions of this size people are separated from more of their hard earned money by unscrupulous builders.
They do this by adding mountains of "extras" as they priced off a set of planning drawings and went to site without the necessary monitoring of the works.
Without possessing a proper contract, drawings or specification, and with an inadequate level fo professional oversight, you could find this job costs €80K not €40K!


ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon as a defence or support - in and of itself - should legal action be taken.
Competent legal and building professionals should be asked to advise in Real Life with rights to inspect and issue reports on the matters at hand.

Hi f9710145! Was wondering how much you ended up spending on your first floor extension? We are thinking of building one exactly the same size, and I was just hoping to have a rough idea of what to expect. Thanks!