Actual cost of extension?

[littlerose12345]

We keep getting told to budget around £1500/1800 per square metre for an extension.

Just wondered what you have found it actually costs if you gave recently completedan extension?

Well our extension is about 1m square but we are knocking down two walls to make one big kitchen and it’s gonna cost about £50k 😂 it really depends what work has to be done

It's hugely dependent on spec, your location, age of property aka whether your house has any foundations to speak of (thanks, Victorians) etc so extremely hard to get a price without speaking to a friendly builder. Do you know anyone near you who's done what you're planning?

According to online calculators our 1.5 x 5.5m London terrace extension "should" cost around £50k. Real cost will be 50-100% more than that at least; but we are (for example) moving WC under stairs, getting new boiler/hot water tank etc etc so the cost is rarely straightforward.

Ours has come in at 1500 per sqm. Then vat on top.

I’m thinking of replacing fluorescent tube lighting with spot lights in my kitchen. Has anyone done this and were there any issues?

@Ohnoohnoohnonononono

Well our extension is about 1m square but we are knocking down two walls to make one big kitchen and it’s gonna cost about £50k 😂 it really depends what work has to be done

I need more info on this!! £50k for 1m square?????

@Ideasplease322 haha. Edwardian terrace, we have a kitchen on a dog leg at the back of the house, with a lean-to with a plastic roof next to it. We are knocking out the walls to make the dining room, kitchen and lean-to one big space. We have a small courtyard at the back so are not extending into it and we are only gaining about 1m square on the floor plan. But we have to have steels and there are lots of annoying things about this job because the soil pipe, gas meter, electricity meter and electricity supply to the house, drains and man hole covers all have to be moved. And then we need to put a new kitchen in and our builder is VAT registered so there’s an extra 20% on top. It hasn’t started yet but I think we will be lucky to get out of it for less than £50k.

Out of interest when your are told 1500-1800 is that for a single storey? I’ve read the second floor is less? Do people find that is true? We are hoping to do a two storey extension across the back of our house (6m x3.5m), but I’m worried it’ll just be too expensive! The maximum we could spend would be £100k, but that would have to include two bathrooms and a kitchen too (midlands).
We are just waiting to hear from the council to see if we can get permission to do it before contacting builders.

Are you in the north? My mums averaged £1500 psqm ( including Vat)....she in Yorkshire.... but my brothers was over £2000 excluding VAT ..... he’s in Berkshire

Our single storey extension is about 25 square metres (2m out from the house along a 12.5m length). We expect the work will end up costing about £95k when it's all finished, which a simple calculation would suggest works out around £3800 per square metre. In reality, lots of this is going on remodelling parts of the existing house, and on fitting out and finishing the new space - not cheap, as it includes a kitchen, utility room and shower room.

The shape of the extension is important: a square 25m² extension in am internal corner of an existing house might need 10m of wall building. To get the same floor area in a wraparound extension which comes out 1m from the house might need 28m of wall.

The point is, you can't work out the cost just on a square metre basis. The site layout, access, what you want to put in the extension etc etc will all affect the price just as much as the area.

We just spent 100k including vat for approx 50sqm double storey. No kitchen though which would have added more. That's in the Midlands

SW london 35sqm extension plus down stairs loo and a roof terrace being demolished snd ceiling being raised so work in the bedroom / bathroom above - building, sliding doors all the way across and 3x roof lights etc cost £100k (inc VAT) kitchen £25k and fit out / painting / flooring probably another £15k plus building regs/ structural engineer and architect do close on £150k way over budget but builders like gold dust !

We are currently half through a 2 storey 80sqm (2 x40) side extension and 25sqm single storey rear extension in the NW and paying £220k inc VAT to second fix. Our architect thought £150k would cover it however we didn't get any quotes near that figure and some considerably more than we are paying!

@MissFritton65 it all piles on so quickly doesn't it - we were told about 80k build etc plus kitchen so about £110k no builders came anywhere near that when they added in second fix and VAT ! we haven't even started building yet !

@Sunshinev the costs certainly mount up very quickly!

Have put on 12mtr by 7 mtr 2 story extension - approx 168 sqmtemrs overall- new kitchen - sliding doors etc - and it cost us 190k - Northern Ireland though

@Cnp41 lucky you; I'm jealous and hope your build goes well.

@MissFritton65 - not sure how to tag but thank you and it is stressful as fook of course but hopefully will be finished up by end of Summer - hope yours is going well too - sounds like you will have loads more space to play around with! Thanks

@littlerose12345 that's unlikely to be enough. If this is a bedroom extension say over existing garage without bathroom ie not wet services then £1800 to £2000 plus vat plus professional fees.
If this is a kitchen diner extension then more like £2700 plus vat upwards.
Unless you're in Scotland or NI.

Due to pricing shocks within the economy (brexit covid Suez Canal shipping issues) items such as timber for construction have risen 40% in the last few months.

Construction/labour wages have risen by 25% in the last year alone.

I think you need to consider a higher budget unless you have family in trade you can help with the build itself.

Ours was approx £23k 8 years ago for 12 square m total - 9m2 at rear and 3m2 at front

Quite a few steels & 2 sets of bifolds but no kitchen involved

@Notjustabrunette we had that done a few months ago.

Because the electrician will have to lay multiple new cables, I guess it's pretty much inevitable that some will have to cross beams within the ceiling. This means drilling holes in timber, so the electrician would need access into the ceiling void either from the kitchen (i.e. some part of the ceiling will have to be taken down) or from the room upstairs (i.e. parts of the floor there will have to be taken up) - we had the latter. Also, our original kitchen ceiling was lathe and plaster and we were told it would be very difficult, if impossible, to make neat holes for the spots and fix them securely. Our kitchen ceiling was being overboarded and skimmed anyway, so no issues with that after all. Otherwise, it's a pretty standard stuff for an electrician to do.

Maybe it's worth starting a dedicated thread to get more responses?