Extension costs north west 2024

Lunielumps

Hi all, 

I've been reading through old threads on typical extension costs per m2 and wondered if these have changed much over the last two years?
We have architects drawings for a 25m2 single story side extension including:
one skylight and one window 
three sets of RSJs to open up the back of the house into the extension
new plumbing for the downstairs wc and kitchen/diner, all new rads
moving the boiler to the other side of the wall it is currently on
full house rewiring

Based in north manchester we have had quotes ranging from £74k (inc VAT) to £144k (inc VAT)
Feeling a bit lost as to what a reasonable price is - this is just to a first fix plastered finish, no flooring/decorating/ not including the actual kitchen. 

Any ideas on a reasonable cost?

FreeBear

It used to be a rule of thumb that extensions cost £1500-2000 per square metre. £3-4K would be a more reasonable expectation in today's climate. Your £74K quote is to the bottom end, whilst the £144K is possibly a bit over the top. But with three steels, I'm guessing it isn't a simple box stuck on the back, so extra costs will be involved.

TELLIT01

The basic box of the extension is likely to be in £3k plus region.  Then you have the full house rewire to add.  The top price does seem high unless there are major access or groundwork issues to contend with.

Material prices have increased massively in the past couple of years.

propertyhunter

£144k seems a bit too high. Consider whether it is cheaper to move if that's an option (appreciate it isn't for some people, for various reasons).

Albermarle

There have been threads on here where there have been misunderstandings about what 'first fix' means in practice. Make sure it is clearly defined and agreed.

boots_babe

You sound similar to us. Our extension will be 21 sqm, no rewire but need smaller old extension knocking down first. 2 steels, 2 skylights.

We are in the North West, Lancashire. 

After much chasing have finally had quotes in. They range from £60k, £80k, £115k to £130k, all figures are excluding VAT.

Bit baffled by the huge variance, but with 2 lower quotes and 2 higher it's not as though there is an obvious outlier.

So like you we are now quite confused as to the best option.

Lunielumps

Thanks all. 
It is a fairly simple box stuck on the side, with some steels to open up the rest of the house so nothing unusual. 

@FreeBear is the £74k unrealistic? i don't want to choose a build low balling to get the job but i also don't want to pay over the odds for no particular reason given its a pretty basic extension. 

Albermarle

boots_babe said:

You sound similar to us. Our extension will be 21 sqm, no rewire but need smaller old extension knocking down first. 2 steels, 2 skylights.

We are in the North West, Lancashire. 

After much chasing have finally had quotes in. They range from £60k, £80k, £115k to £130k, all figures are excluding VAT.

Bit baffled by the huge variance, but with 2 lower quotes and 2 higher it's not as though there is an obvious outlier.

So like you we are now quite confused as to the best option.

Builders seem to often quote high when they are very busy, rather than just saying they do not really want the job.

gzoom

Our very extensive and complex (35 tons of steels) refurb/build is coming in at just under £2500/sq meter as we head towards completion. That figure include a decent size/spec kitchen, £5k front door with 4.5 meter sections of glazing with alu frames, all new wiring, new boiler, fully tiled down stairs etc etc.

A variation in quotes is quite normal, we had a 50% difference between the cheapest quote to the most expensive, and 2 out of 6 builders who came to the house didn’t even bother to quote. 

Absolutely no need to overpay, but do make sure you go with a builder you can trust, is willing/comfortable referring you to previous customers for feedback etc. The really good builders also should be booking jobs into 2025 now, I would be very careful for of anyone who can start straight away. Demand has softened but good builders will always be busy.  

https://forums.moneysavingexpert.com/discussion/6469163/our-home-renovation-project-opposite-of-mse-philosophy#latest

Doozergirl

Lunielumps said:

Thanks all. 
It is a fairly simple box stuck on the side, with some steels to open up the rest of the house so nothing unusual. 

@FreeBear is the £74k unrealistic? i don't want to choose a build low balling to get the job but i also don't want to pay over the odds for no particular reason given its a pretty basic extension. 

Albermarle said:

boots_babe said:

You sound similar to us. Our extension will be 21 sqm, no rewire but need smaller old extension knocking down first. 2 steels, 2 skylights.

We are in the North West, Lancashire. 

After much chasing have finally had quotes in. They range from £60k, £80k, £115k to £130k, all figures are excluding VAT.

Bit baffled by the huge variance, but with 2 lower quotes and 2 higher it's not as though there is an obvious outlier.

So like you we are now quite confused as to the best option.

Builders seem to often quote high when they are very busy, rather than just saying they do not really want the job.

The fact that you mention steels, plural, makes me feel like this isn't a simple box at all.  A simple box would have zero steels, a fairly simple box would have one.  More than one becomes interesting and that moves me out of simple.   Introduce a full rewire and the associated (unknown but could end up taking an entire house back to brick in some cases) works to make good and you just can't give five bullet points and expect any degree of accuracy. 

You can employ a quantity surveyor to do a breakdown and see how your quotes compare, or you can look at which of your quotes are most comprehensive and can be trusted from a contractual point of view.  

What kind of specification have you provided to those quoting?  Presumably more than five bullet points, or at least their quotation has come back with more than five bullet points!  

What else differentiates these builders?  What accreditations do they have, what scrutiny have they put themselves up for when *anyone* can decide to call themselves a builder? 

https://www.fmb.org.uk/find-a-builder/ultimate-guides-to-home-renovation/how-to-choose-a-builder.html

Albermarle

gzoom said:

Our very extensive and complex (35 tons of steels) refurb/build is coming in at just under £2500/sq meter as we head towards completion. That figure include a decent size/spec kitchen, £5k front door with 4.5 meter sections of glazing with alu frames, all new wiring, new boiler, fully tiled down stairs etc etc.

A variation in quotes is quite normal, we had a 50% difference between the cheapest quote to the most expensive, and 2 out of 6 builders who came to the house didn’t even bother to quote. 

Absolutely no need to overpay, but do make sure you go with a builder you can trust, is willing/comfortable referring you to previous customers for feedback etc. The really good builders also should be booking jobs into 2025 now, I would be very careful for of anyone who can start straight away. Demand has softened but good builders will always be busy.  

https://forums.moneysavingexpert.com/discussion/6469163/our-home-renovation-project-opposite-of-mse-philosophy#latest

As this is a much bigger job than the OP is looking at, you are presumably benefitting from some economies of scale in your cost per square metre.