Extension Price Sanity Check

[woodpeckerx]

Looking to get a sanity check on appox per sqm price for an infill single storey extension with flat roof, floor area ~16 sqm.

~8m of new footings, brick/block cavity wall on new footing, 2.6m wide bifold door and 1 small window so hardly any brick/blockwork, rubber flat roof. Then knock into house with RSJ over opening, quotes are insane (IMHO) what sort of price should this be, plastered finish only, screed floor, minimal electrics, 4 spots, 2 sockets, 1 rad.

TIA

 

[noseall]

Looking to get a sanity check on appox per sqm price for an infill single storey extension with flat roof, floor area ~16 sqm.

~8m of new footings, brick/block cavity wall on new footing, 2.6m wide bifold door and 1 small window so hardly any brick/blockwork, rubber flat roof. Then knock into house with RSJ over opening, quotes are insane (IMHO) what sort of price should this be, plastered finish only, screed floor, minimal electrics, 4 spots, 2 sockets, 1 rad.

TIA

£35 - £40k.

 

[thomp1983]

Depends where you are but somewhere between £1500-2000 per square metre is the norm these days.

It's the sort of project you could probably save money by sourcing your own trades and managing it yourself but you'd need to be on the ball making it all come together.

 

[Murdochcat]

£40 k plots 20% for budgeting purposes

 

[Ivor Windybottom]

Thought this was a DIY forum? £15k plus some sweat.

 

[woodpeckerx]

Thought this was a DIY forum? £15k plus some sweat.

Job's yours, when can you start, kettle's on and biscuits ordered

 

[mrrusty]

Y. I'm with @Ivor Windybottom. Last couple of years I've built 9 x 3.5 brick/block garage with slate roof and 4 windows - single skin with cement board cladding and slate pitched roof on concrete reinforced raft. £10K materials (2020). This year, 6.5 x 3.5 timber frame SIP building with pitched slate roof, cement board cladding, timber sub-base on concrete pad founds - 4 windows, french doors, lined with PB, skimmed, leccy, etc for £17K.

It sounds very doable to me for £15K materials and a bit of sweat.

 

[PA-18]

Depends where you are but somewhere between £1500-2000 per square metre is the norm these days.

We’ve been told by our designer £2k per sq meter, East Midlands.
We did get a single quote out of the five outfits we had round and he was closer to £3k m2.

 

[Ivor Windybottom]

We’ve been told by our designer £2k per sq meter, East Midlands.
We did get a single quote out of the five outfits we had round and he was closer to £3k m2.

Ahhh, there's the first mistake.

Your designer is sub-contracting to a builder, who sub-contracts to a digger driver who hires his digger. You have to pay enough for everyone to get their cut.

Meanwhile, I phone a bloke who owns a digger, I give him £300 and I have all my footings dug. Then the concrete company turns up the next day, I pay them. I could then employ a bricklayer but have decided to DIY from this point onwards. You can juggle trade or DIY as you prefer, but I definitely don't want to pay middlemen.

 

[noseall]

I could then employ a bricklayer but have decided to DIY from this point onwards.

 

[Ivor Windybottom]

I've built a huge retaining garden wall before, I learnt lots and was 70% happy with my work. I've seen some of your photos, your stuff looks great. But I'm not in Staffordshire. I've looked at the local newbuild estate and have seen what the average brickie I'm likely to end up with will produce, think I might be better DIYing.

Have de-skilled as much as possible, bought Blakes profiles, block dollies and Fitzbrick Dory Blocks. Should all make it reasonably idiot-proof. Also have now decided to leave it until the spring as everything's so damp and gooey now. The bricks are LBC, they look like they were packed wet so need air-drying in some sun after opening.

 

[Notch7]

ook like they were packed wet so need air-drying in some sun after opening

Yeah bricks must be bone dry before laying

 

[PA-18]

Ahhh, there's the first mistake.

Your designer is sub-contracting to a builder, who sub-contracts to a digger driver who hires his digger. You have to pay enough for everyone to get their cut.

Meanwhile, I phone a bloke who owns a digger, I give him £300 and I have all my footings dug. Then the concrete company turns up the next day, I pay them. I could then employ a bricklayer but have decided to DIY from this point onwards. You can juggle trade or DIY as you prefer, but I definitely don't want to pay middlemen.

I think our designer is just putting us in touch, not managing it, maybe he gets a finder's fee (which of course I will end up paying) I really don't know. However it doesn't matter as the builders aren't communicating.

I'm a big fan of DIY, I can drive a digger, got the electrics city and guild, only thing I won't do is plastering as once you start you're committed and I am not that good. But, with this build, I'm thinking the founds/walls/timber roof need to be done by the skilled trades. These new Part L regs seem a ballache, noseall on here was saying maintaining a 1cm cavity is hard work, so what chance do I have? None. I could probably hack up a wall with batts, but the mrs wants a lot of glass and walls that are not filling the room, so it has to be PIR.

We've all built up a list of names and phone numbers on our lane, of old time served lads who do a good job but just want to do it in their time now, and I'm happy to chew the fat with them too.

So I reckon I can get it done for < £1k m2 using certain trades, and doing the rest myself. I shall let you know. I respect your desire to DIY it all, if i was younger and wasn't so damned busy at work I'd give it a crack, oh and also if I was a bachelor would help

 

[Ivor Windybottom]

I'm more out of necessity than choice! I've found before that it can take as long as DIY to find and supervise trades, even ignoring the money side of things.

I've never plastered either. But the plasterer I got in a few years ago was rubbish, if it was an important room and not just my office I'd have hacked it off and started again. There's a big gamble in getting trades in, you really can't tell what you're getting however much googling you do. There's no regulation in the UK, it seems that buying an old van is all that's required for most trades.

 

[dormermike]

Been getting quotes of 3.5-4k per sqm for single storey 16 sqm extension in south Wales.