Two storey extension

[123rd]

Hi all
We are trying to get builders/quotes for a 4 m two storey extension. Not to fancy just a square on the back of the house type thing. We have had one quote back which was double what we were expecting. This was based on two other friends having similar sorts of work done. So, what would you expect to pay? We are south east-not london.
Also,as time is ticking on,would you put off having major work done until next spring/summer or would you mind doing that sort of thing in the autum/winter. Would we get it any cheaper in the winter ( clutching at straws!!)

Before we bought the house we had a builder come round, we explained the sort of thing we were after and he said £70k. But obvs we didn't have exact requirements. So, even expecting around £100k I don't think is unrealistic.

We got a builder round to 'have a look' before we starting planning our extension. We were told it would be 70k at the absolute maximum. I don't know what that included though.

I was a bit naive!

We are including wuf heating. But that's costed at around £2.5k. Not having bi-folds, just some french doors. No flashy anything really.
The cheaper quote has included all tiling and decoration.
Our architect didn't want to get involved in pricing really.
Did I say before, two builders haven't even bothered to quote as they are so busy
Anyone had a non vat reg builder? Does that bring any risks?( assuming we could find one anyway)

We are breaking ground next weekend, 2 storey side extension, bigger kitchen, utility room and bathroom with a shower, garage and 4th bedroom, most of the work we are doing it ourselfs (Well Other-half is) other wise we have individual tradesmen.. It will take longer but work out so much cheaper...

1st floor extension in South East at 8m2 plus few other bits at just over£17,000 plus vat. However we asked for about 10 builders to quote, got 6 quotes back based on same architects drawings and spec and ranged from £15,000 to just over £29,000 so worthwhile getting as many builders round as possible

I would cost on £1500 m2 as a guide.

Thanks. Night swift that was the equation that I was going to ask about. Is that just build cost? Ie not internal " things" & I know this is a REALLY lame question but how do I work out the 2m
I know its a 4m out, and I'm know its about 6m across. 2 storey. How do I work out the total?? Do I need any other measurements?

I think (and I stand to be corrected) when people talk about a build cost of £1000 per square metre (or £1500 etc) its based on the additional space you're gaining, not the footprint of the extension. So for your extension - 4m x 6m it would be 48 square metres as the starting point.

Well that does add up. We were told-v approx -about £70k before we bought the house.

I would add extra for kitchen. That would be room but fully kitted finished and with electric and heating but not fittings like kitchens.

Our extension is exactly that - 4m x 6m and two storey. It is 48 sq m in total.

I think the £1500 per sq m figure around us locally is for a basic shell only.

Yeah, so your sums do add up. Ours at £130k & £160k don't seem to. (Our quotes didn't include the kitchen cupboards or bathroom suite)we are now waiting for two other quotes. Another thing that is annoying is the massively different info/advice all the builders have given. Like total opposite advice!!! V frustrating.

Are they quoting on a full set of plans and spec? Or is it we want to do this kind of thing quote?

Yes, full set of plans. Very detailed plans.