# Cost of first floor extension



## f9710145 (17 Apr 2011)

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


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## choccy (18 Apr 2011)

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 !


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## f9710145 (18 Apr 2011)

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.


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## RIAD_BSC (19 Apr 2011)

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...........


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## onq (19 Apr 2011)

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.


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## f9710145 (19 Apr 2011)

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


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## onq (21 Apr 2011)

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.


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## s7178280 (18 Apr 2014)

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!


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