Renovation/extension costs for 3 bed terrace house Dublin


Tendering at the moment for renovation & extension of a small 3 bed terrace house.
Best quote so far was 63k not including VAT for:

27 sqm extension with flat roof - including floor finishes, ceiling and wall finishes but not including Window/Sliding door/Roof-light.
Includes electrics for extension, keeping most of existing wiring in house.
Install GFCF, new boiler, plumbing and associated works
Reconfigure downstairs for new bathroom, utility room - there is just one bathroom which is downstairs
New floors downstairs in existing house - small area
Insulate attic, drylining existing house.

The quote does not include new windows, hall door, kitchen, sanitary ware or painting - which I also need.
Is this a reasonable quote or within what people would consider reasonable?
It is more than Id have expected to be pay being honest, but I understand that you get what you pay for. I have an architect so maybe the spec of the extension is driving the cost.

Any advice would be much appreciated.


Hi Lexa,
We live in a 3 bed mid-terrace in Dublin (Northside). We’re at the end of a job almost identical to yours. Having put the job out to tender we found the range of prices being quoted was very wide. We eventually chose the builder who came with the best recommendations and a very fair price which was clearly broken down for us.This helped us on a number of levels,not least of all the ability to row back on one or two luxuries which just didn’t make sense in the long run. The price of ours came in at around half of what you’re being quoted. We had 3D plans drawn up beforehand which helped get things started straight away. The range of prices we were quoted was 25,000-45,000.
We are very,very happy with the work and inlaws in the building trade have commented on the quality of the work.
I don’t see a PM button here but you would be very welcome to come and see the work to date if I could PM you?
I’m new to the PIN- can I publicly link to the builders website?

The best of luck with the renovations whatever you decide!

In Dublin I take it? Doesn’t sound unreasonable. +10-15k for the other stuff.

Would you consider contracting a quantity surveyor to give impartial advice as to the costs?

Job done a year ago in Bray:

380 sq foot single storey extension and complete refurb of 600 sq ft house (100 years old)

  • demolition of old lean too and gutting of old house
  • 80mm insulated plasterboard in new and old, skim finish
  • sloped man made slate roof / brick facade on extension
  • incl 4 x veluxs. Other windows doors supplied by me
  • all electrics
  • all plumbing incl. boiler and rads (sanitary ware by me)
  • fit kitchen (supplied by me)
  • fit flooring (supplied by me)
  • all painting (final 2 coats paint supplied by me)
  • garden walls rebuilt around 25 sq meter garden and rendered
  • patio laid (slabs by me, large centre circle by him)
  • all old house plaster taken out (walls and ceilings external and internal walls) and downstairs flooring taken out and new downstairs insulated concrete floor installed (with radon barrier)

Cost 55K ex vat

Terraced, semi detached, detached? Site access?

Trying to compare prices without knowing more about a project is pointless. OP should either get a QS to price it (and possible do a Bill of Quantities) or go to enough contractors that s/he is satisfied that the prices coming back are reasonable - that would be a max of 5.

Thanks for the advice.

I have 3 quotes so far, but not sure if it would be worth tendering again.
I have compared the 3 quotes and the contractor that came in lowest overall was higher on a few areas than the most expensive quote so maybe there is room to bring the cost down on some of these things.

How much would you expect to pay for a QS?

Would you consider 9k reasonable for installation of GFCH, new boiler, rads, controls, zoned heating.
Quote for electrical installation is 7,100, but that is not a full house rewire, that is only wiring extension with some additions to existing house. I thought that was high given I’ve heard of people getting a full house rewired for about 4-5k.
Also demolitions and alterations are 6k. This is really only knocking part of back wall and slightly altering the existing bathroom layout and stipping out whatever is there. Is this what you would typically expect to pay?

Appreciate all your advice.


Do you know any builders from outside of Dublin? For a similar job, I got a 2 quotes. One from a Dublin builder and another that I know from Wexford. The Wexford builder was almost half the price (New flat roof on a 15 sq meter kitchen, 3 rooms plastering, electrics, new window, back door, 2 rooms warm boarding, new ceilings in 2 rooms). Also saved money by doing the painting and some of the laboring myself and directly employing the tiler, floor fitter, plumbers. Furthermore, materials are about 30% cheaper in building providers outside of Dublin

Are you going direct hot water and central heating (you don’t mention a hot water tank)?

We’ve well insulated and never turn on the rad’s upstairs as the heat makes it’s way up their anyway - so I don’t see the sense in zoning a 1000-1200 sq ft house. There’s no need to go overboard on rad size either. A 7 day timer doesn’t cost that much.

9K sounds a bit toppy to me. I’d specify which components to use (e.g. myson thermostatic valves, Glowworm boiler) as a lot can be saved by the contractor by using cheap components.

I’d advise against having any plumbing in the slab. Have it all above ground and future leaks will be more easily fixable. Take plenty of photos of plumbing in place before it gets covered over. Witness a leak test being being carried out (overnight/weekend)

We’ve 20 points in the 380 sq ft (galley kitchen, dining area, bathroom, stairwell). A point could be a socket, a cooker isolator, a dishwasher point, a light switch (even if switching a couple of spots, a supply for the boiler, etc.). If it cost 7K for that it would work out at 350 euro a point. Ex VAT a sparks is going to be charging say 200 a day, the parts/cable per point cost another 50 (being generous). Even if it took the sparks a day per point, he’s overcharging to the tune of 100 per point. And it won’t take a sparks a day per point. This is fresh build (in the main). Assumption here is that all is surface mount - that he doesn’t have to chase walls to lay cable in.

Has he got to install steel to support the structure above whatever he’s knocking out. Or is he simply cutting an opening an pushing the material away? A labourer with a consaw and few hours will do the latter. Without knowing more about the specifics of alteration, it’s hard to comment: it take little to strip out but can take a lot to alter.

You make mention of an architect. Is he not in a position to throw his eye of things for you?

Thanks York, that’s really helpful.

I did mention to architect that I needed to make savings, so we took out things, rather than look at spec. So I took out ensuite, porch, stove, keep some existing light fittings sockets rather than full rewire. Probably would have been more helpful if architect relooked at spec and advised savings that way. (although I have put the ensuite back in now which is an extra 2900, but figure better to do it now when having other work done).

I also mentioned looking at the cost of each item in the tender, but it is done on a lump sum contract without quantities, so he didn’t seem keen to discuss the various costs with the builder involved. I may have to push him on this a bit as it seems a bit ludicrous to agree a contract without knowing specifically what is under each heading, other than it covers the spec in the tender.

Plumbing was going to be condensing boiler but I think we have changed to normal boiler so I think new hot water tank. Not totally sure and know very little about plumbing. I guess I can ask to get rid of zoning and simplify things and see if that saves anything. House is only 650sq ft. - without extension.

In terms of electrics - full rewire was 7100, we decided to use existing lights, sockets in existing house saving 900. So 6,200.

I think there may be bit of steel for the demolition, but we aren’t taking down a full back wall, and there isn’t a lot of stuff there to remove. So 6k may be over the top. I don’t have a breakdown of what is covered in the 6k.

Would it be unreasonable to suggest to architect to get a full breakdown of what is included in each heading?
He said it wasn’t normal for these types of small contracts. Like I said, no problem paying the going rate for work, but don’t want to be gouged either. If savings can be made it means my window and kitchen budget will be less tight.
Should I push it back to architect to look at these costs? He just seemed to take the quotes in the tender as being what they were without any scrutiny.


Who’s running the job, you or the architect? If you’re really not equipped to do it yourself, then the architect should be engaged (and paid) to run it for you. Someone needs to make sure the build is happening as it should, with regular visits to ensure all is well (especially before seismic events like foundation inspection, before slabbing, leak test, etc). If the latter, then the architect should be advising you on proper staging: a porch can always be nailed on later, rewiring on the other hand should be done now.

To be fair, it’s not a huge job and builders won’t be inclined to pour oceans of time into a precise breakdown for a job they might not get. In all likelihood, the builder is basing costs on experience without actually knowing what the plumber is going to charge for the jop (he mightn’t even know which plumber he’s going to get just yet)

The main thing is that there is a detailed spec (e.g. specifying which brand in the case of items where there can be significant price differential, for example, the boiler) and that there is someone going to ensure that spec if met.

Are you really sure you need an en suite in a house that size? Is it possible to put a larger extension on it (you can go up to 40 sq m without planning)

Per above, I’d question not rewiring the house at this stage (and the wisdom of an architect who advised any differently). It’s not a job to be done later. By all means use the old sockets and switches if they look sound - bearing in mind that removing them and cleaning them up takes time which must be paid for (frequently, recycling stuff ends up costing more than going new - so limit to things that really count like an old fireplace or roll top bath)

There’s nothing to stop you placing a precise spec on and seeing what happens. It sounds steep to me (notwithstanding my comments above on bundled costing)

As an aside, you can save a chunk of money by shopping around for surplus windows and doors since you can have the opes made to suit. Mac’s Salvage, for example, often have job lots of new stuff and there’s no big deal in installing a secondhand window unit.

To detail costs the builder, to scrutinize cost the architect. Providing you’re prepared to pay them both for their work it should be possible. Builders aren’t so hungry for work no more so are less prepared to jump through hoops in the hope of getting a job.

As a final note. I’d advise you setting up an excel sheet (if you’ve not already done so) and list out every cost centre associated with the job: architect fees, builders cost, items you’re buying yourself (down to the very last detail), planning costs, certification costs. Every single thing you can think of now and as you progress. Put in an estimate for that which you don’t know and put in a contingency at the end. Keep it up to date as you go. You’d be amazed how the incidentals stack up and if you don’t accrue for them now you could be surprised later.

Architect is running the job and being paid for it, including tendering, site visits and final sign off. I’m not really equipped to do it.
However I guess I would have expected him to at least question some of the costs in the tendering process.

I compared each of the quotes I had received to see if there were any big variances on items between quotes and where this builder is higher than others I asked why. Architect just said that builders include different things under the headings that that was it.
So for example for Floor and Floor finishes for downstairs 38sqm (new and old part) is 6k and 4k. I know what floor finishes are and have a price for material. I have no idea what floor is. And that was more expensive than other contractors by a fair bit.

In terms of electrics, house was rewired recently enough, so the proposed changes were more aesthetic than anything.

There is no bathroom upstairs which is why I think it would be useful to add an ensuite at this stage. Otherwise to put bathroom upstairs would lose a bedroom which I don’t really want.

The spec does say brand of boiler, but nothing about components and that sort of thing.

There is a big double door at the back 3.3m wide. I think that’s gonna be the big expense compared to the windows. So I also need to budget for that too.

i understand that builders won’t want to spend time doing big detailed costs, but I suppose how can I satisfy myself I’m not being ripped off? Would it be better to engage a electrician and plumber myself perhaps?

I get all my kitchens done through a guy from Galway.
Very good work and much cheaper than a Dublin contractor.

He drives to Dublin and does the whole job in a day.

I’d be less concerned about that than I would be that the spec is detailed enough and supervision is rigorous enough to reach the destination desired. The tendering process itself should provide the necessary competition - with perhaps previous experience with the builder or interviewing to establish a gut feel about likelihood of a trouble free build being sufficient to ensure the overall target is met. It’s not in the architects interest to take on a cowboy.

Sweating out the detail costs could end up costing more than approaching it more globally

I think it should be possible to compare standalone items like a rewire or the plumbing since these can be compared in apples vs apples fashion. But again, it’s the overall price and satisfaction that the builder is the right one for the job which matters most. It isn’t a big job so reasonable enough to approach it in this fashion.

Fair enough. Your architect should be in a position to tell you what addition/modification is a low cost item and what is more involved. If you had a list of all the things you want but which are negotiable, he/she should be able to categorize them A, B, C in order of expense. That way you might find you can get 60% of the extras for very little extra cost.

Whatever you do though, get the fundamentals sorted now and leave things (like a porch) which can be added on later. You don’t want people back erecting new partition walls inside your house at a later date.

Fair enough II. I’ve just a downstairs bathroom and it’s fine. That’s with 950 sq ft. An en suite strikes me as befitting a house with more space to burn. Just personal preference. It’s not like I’ve far to go for a wee no matter where I am in the house :slight_smile:

Absolutely not! There will very likely be hold ups on the job: contractor A gets in the way of contractors B’s work. Or contractor C drills a hole through Contractor D’s plumbing and contractor D has to come back to remedy. Since there’s no way to tease out who’s fault what is, you’ll end up footing for the extras. Much better to let it all funnel through a single coordinator / responsible person. The Builder.

Much depends on how diligent your architect is. If a good 'un then the tendering process will produce a competitive result without having to sweat out the detail. If not, then not, or less so.

Like I say, think through all conceivable costs and maintain some kind of contingency for the unexpected.

Oh, one other tip. If planning to retain an open fire/install a stove, consider a chimney cctv inspection to make sure the flue liner is sound enough. A stove would likely see the flue lined but if it’s collapsed in then you’ll face expense (and a lot of mess) later. It’s a frequently overlooked item on old houses.

A CCTV survey costs around 250 and you get a dvd video of findings. Don’t be scared by hairline cracks in the flue liner - they don’t matter (even if the chimney guys recommend otherwise, they provide the relining service afterall). But if chunks are missing or have falled into the flue blocking it off then that’s another issue

My architect indicated 800, I don’t know if that’s fixed or a proportion of the total (which’d be 1-2%).

@York, +1. Sound advice.

DoneDeal is your friend.

Rational stuff is modular so you can build up the width you need.

(Thanks Coles2!)

Thanks a mil York, that’s super helpful.

Architect is familiar with this builders work so that is good. However I have asked him what is included under each heading in the tender to make sure nothing is missed or double counted and he doesn’t know or seem bothered other than it’s a competitive quote apparently.

I asked the architect a few basic questions like:
Why is electric installation cost quoted so high (was it something with the spec) and would using a cheaper boiler reduce cost? He has specified a Viessmann which I understand to be one of the dearest boilers. His response is just – that’s a question for the builder, but that builder is competitive and they are unlikely to provide a further breakdown of costs.

For me that means nothing if you are paying over the odds for some of the things i.e. electrics. He doesn’t seem to want to question the builder on any of the costs to see if savings can be made. His attitude seems to be just take it or leave it. Is this normal?

I guess I could re-tender but I am already a couple of months behind where I want to be and would like to be in house for Christmas.

Another question I asked was does dry lining and attic insulation qualify for grant? He says that’s something for me to check with SEAI to see what qualifies. Should an architect not know these things if they are designing the spec?

Is it unreasonable for me to expect the architect to be looking at these things?
Seems fairly basic to me. I am paying for him to manage the tender. I guess I just would have expected him to be a bit more clued in re: costs and ask a few simple questions.

I find it hard to agree a contract for a significant sum of money (for me) without actually knowing what’s included to making sure nothing is missed.

Is my architect being lazy or am I expecting too much?

Having been ripped off by builders for renovation work before, I wouldn’t let one within an ass’s roar of the place if they can’t tell you what you’re paying for. And your architect’s attitude sounds equally remiss. You’re the one paying the money, you are entitled to the information or take your business elsewhere. I wouldn’t let myself be rushed into anything. Look at it this way – do you think the builder came up with the quote without giving any thought to specific costs and therefore his profit margin. Did he heck! From past nasty experience, I would treat the lack of forthrightness as strong evidence that he’s planning to take you for whatever he thinks he can squeeze out of you. Don’t fall for it. There are plenty of builders who will give you a more straightforward quote. If your architect can’t find them then it’s time to start considering ditching him too. Have lots of family abroad who have built and done renovation work, and from years of discussing it and comparing it to my own experience, Irish get totally shite service in almost every walk of life, primarily because they’re willing to put up with it.

All in all I think the quote isn’t too bad, but as superman has said, it’s impossible to say.

It certainly appears that the cost of the electrical work is eye wateringly excessive, and I would expect a full rewire of a house of that size to cost absolutely no more than €4.5k (ex Vat). I have a quote on a complete rewire of 2 bed 1200sq ft at €3.8k ex Vat, with a further €500 of associated works and a margin bringing it up a bit more, but certainly a long way off €7.1k for half the job.

Tell the Architect that the electrical cost is too high and that you would like to explore the option to use an alternative electrician. When faced with a lower quote for the electrical work the builder will adjust his price accordingly. An honest builder will have no legitimate reason not to use the client’s electrician as long as he is RECI registered, insured, and professional.