Extension @ £2,600/sqm...

Soldato
Joined
25 Sep 2006
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14,143
Morning All,

My OH is looking to extend her 3 bed-semi by knocking the rear kitchen wall out to create one large kitchen/diner, single storey 15sqm (6m wide, 2.5m deep).

We've been surprised by some of the quotes received having believed the £1-1.5k/sqm estimate found in several places on the web, to be a good steer. Location is Milton Keynes, Bucks.

Yesterday's quote came back at £40k (inc VAT) - for a block & brick plastered shell, excluding kitchen and flooring but including some minor drainage works and plumbing work to move the kitchen to the opposite side of the room. A couple of other builders have also been north of £30k.

To help with a keyboard estimate the the extension will include three inexpensive windows and one pair of French doors and a flat roof. Steel work is required to span the width of the house to support the rear wall.

Site access is very good and the area itself is spacious so shouldn't present any difficulties.

Have we been unfortunate with who we've had in to quote or is there perhaps something making this job pricier than anticipated?

Thanks.
 
Tea Drinker
Don
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13 Apr 2010
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Sunny Sussex
No chance at 1-1.5k sqm

Everything I’m pricing at the moment is, for a small extension north of 1,700 sqm plus vat the majority more than £2k sqm plus vat.

Do you have architects drawings? Does it have planning? If so send the pack to Estimators Online and they’ll price it breaking it right down to how many screws and sheets of sand paper you’ll need.
 
Soldato
Joined
7 Sep 2008
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5,510
But what exactly does that quote include?

I paid 22k for a 6x4m extension about 3 years back, but it did not include the sky window, door or normal windows. the 22k was just for the base build up to including the roof and a skimmed finish. it was a good price at that time but I'd imagine things are slightly more expensive nowadays.

doesn't hurt to keep shopping around though get some more quotes.
 

Jez

Jez

Caporegime
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18 Oct 2002
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33,073
£1k near impossible. I just built a side 1.5 storey of 21sqm footprint for around £1k/metre footprint or around £580/metre all told (inc the loft room in that part), but this was doing all of the work (literally) other than bricklaying, roof structure, and concrete pour myself, paying cash to the bricklayers and sourcing all materials from all over the internet.

As a finished managed product there is no way anything like £1k/metre will be doable on a smaller scale, you'd need to scale right up to a full 200sqm house type structure to achieve that.
 
Tea Drinker
Don
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Sunny Sussex
doesn't hurt to keep shopping around though get some more quotes.

It does it hurts the industry and firms pricing, each quote will cost each firm and just simply asking for more quotes very rarely results in lower like for like quotes.

Anyone with a vested interest in you paying for their services will undoubtedly low ball the costs, architects often do this so they get their fee up front and leave the customer with a load of plans they can't afford.
 
Soldato
Joined
5 Apr 2009
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22,857
We've been surprised by some of the quotes received having believed the £1-1.5k/sqm estimate found in several places on the web, to be a good steer. Location is Milton Keynes, Bucks.

I think the main issue is wherever you've read that £1,000 to £1,500 is the going rate - when I looked recently most places were suggesting £1,500 was bare minimum for a basic quality extension, especially so in the south east. You have to be careful of whether these suggestions (and your quotes) are including or excluding VAT too.

Also bear in mind scaling - a lot of the costs will not reduce significantly from a 25sqm extension to a 15sqm one - a smaller extension is going to be relatively more expensive per sqm and most of the online guideline suggestions seem to go with 25sqm examples for a 5x5 extension from what I remember.

I've also never found the online estimates very clear on what they're allowing/assuming for the entry into the existing structure - creating a big open space with a large steel beam due to removal of an existing supporting wall is obviously going to cost more than knocking through as a simple extra room with a double/single door access which I don't think many of the 'online guide prices' allow for - they assume for example that you're adding a 5x5 room with a simple doorway, whereas what you're doing is increasing the size of an existing room by removing a 6m span of supporting wall.
 

daz

daz

Soldato
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18 Oct 2002
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Location
Bucks
We are adding 90sqm on two stories as a side extension and everything is coming in at £2,000-£2,400 per square metre (£180k-220k)
 
Soldato
Joined
7 Sep 2008
Posts
5,510
It does it hurts the industry and firms pricing, each quote will cost each firm and just simply asking for more quotes very rarely results in lower like for like quotes.

Anyone with a vested interest in you paying for their services will undoubtedly low ball the costs, architects often do this so they get their fee up front and leave the customer with a load of plans they can't afford.

we don't know what that 40k includes yet but....

40K for a 2.5m x 6m extension still sounds expensive to me.
 
Permabanned
Joined
18 Jan 2008
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18,974
Location
Fylde Coast, Lancashire
For ref our extension build starts next week - single storey, flat roof, out the side, 18sqm, comes in at 31k but that's just bare plaster/bare floors, plumbing/electrics put in place for a kitchen install - so that's approx 1.8k per sq m for a bare shell. I'll be fitting the kitchen myself.

Things are cheaper up north though.
 
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