extension costs ball park figure

[thinfourth2]

We are looking at building an extension which will be a lounge/dining room.

We have a space which is 5m x 10m to drop it into and we are thinking of a 1.5 storie with a double hieght space over 3/4s of the room

I know for newbuilds you are looking at about a grand per m2 does this apply to extensions?

[shimmey69]

as a rough guide yes £1k per m2 but as always depends on level of finish, current building structure etc etc etc

Hope this helps??

[JR]

As above but I think that £1K is quite a low figure. £1.5 being more reasonable for extension costs. Given how I interpret your spec I'd say £2K/m2 so £100K.

[dave_s13]

Just pray your ground conditions are good. I needed to mini-pile mine so got about £6k worth of stuff buried in the ground.

I think 100k is maybe a bit on the top side but don't underestimate how much you can spend.

We did a rear/side and part 2 storey job on ours and I think we've spent about £75k. I stop counting after a while, it's too scary. Sorry I can remember the sqm but I think it is somewhere around 55-60sqm of new floor space.

New kitchen/bathroom/fireplace/ensuite in there.

I did all the groundworks (not piling itself), mods to drainage, a lot of manual labour, fitted kitchen, flooring, joinery myself, all decorated by us too. It would have been another large wedge on top if I'd not done all that.

Would I do it again.

No.

well, maybe

[thinfourth2]

dave_s13 said:

Just pray your ground conditions are good.

If you want to dig any deeper then about 12 inches then you need a JCB with a pecker as its basically solid rock. I've been in the "dining room" with the 3.5 ton digger and a narrow bucket and it can't get any deeper then 12".

It is hardcored and gravelled and is currently where i park the unimog

Pic with a boat parked in the "dining room"


The walls are fked and need to come down

Edited by thinfourth2 on Wednesday 2nd November 13:28

[Muncher]

All I can say is hopefully I'm about to embark on a 120sqm extension and I'm hoping it doesn't cost anywhere near £1.5k/sqm!

[dave_s13]

Muncher said:

All I can say is hopefully I'm about to embark on a 120sqm extension and I'm hoping it doesn't cost anywhere near £1.5k/sqm!

Unless you're doing a big chunk of the work yourself, that is what it'll cost, or thereabouts.

[Muncher]

dave_s13 said:

Unless you're doing a big chunk of the work yourself, that is what it'll cost, or thereabouts.

We will be and have a lot of contacts meaning for a good chunk of it we won't be paying "normal" prices.

[dirty boy]

This is a picture of what i've started

6m x 5m (ish)

I'm having a flat roof though (circa £1.5k for a fibreglass jobbie) although I would estimate, given my experience with designed trusses, and assuming you're not requiring fancy tiles, that a pitched roof could be around £1000 more? (£1k for trusses max, £500 on tiles and battens, £500 on labour - days work for two guys? roughly + bits - lead?)








Lots of moving of drains, PITA.

Currently just shy of putting the roof on, the joists are in place top and bottom, so it looks like the shape of the room at last, but we've got to bring the brickwork up, and also at the front.

I've also put in a downstairs cloakroom, taking out the old utility room, spent £407 on a toilet and sink/tap.

My total cost to date, including the toilet, planning, architect, bits for moving the washing machine and tumble from what is now the cloakroom into a new utility at the back of the garage.

£5961.18

Bear in mind i've got my hands dirty, labouring for the brickie, having his materials ready for him (although he'd always moan about where i'd placed them or stacked them or something!!!)


Gives you an idea of costs i've incurred. Good luck!! I wish I knew more about what I was about to undertake on all of my building work.

Also, bear in mind, mine's all being done "as and when"

20-Jun-11 Building Regulations Waveney DC 264.00
23-Jun-11 Architect Barry 500.00
23-Jun-11 Planning Fee Waveney DC 150.00
4-Jul-11 Labour John 50.00
5-Jul-11 Labour John 50.00
6-Jul-11 Labour John 50.00
7-Jul-11 Labour John 50.00
8-Jul-11 Labour John 50.00
11-Jul-11 Concrete Mix-a-man 312.00
12-Jul-11 Labour John Smith 50.00
12-Jul-11 Telescopic Underfloor Vents Travis Perkins 24.48
12-Jul-11 Air Bricks Travis Perkins 6.24
12-Jul-11 Building Sand (1t) Travis Perkins 43.80
12-Jul-11 Ordinary Portland Cement Travis Perkins 19.50
12-Jul-11 Trench Blocks (440x215x300) Travis Perkins 89.10
12-Jul-11 Re-grades (Sub DPC bricks) Travis Perkins 89.10
19-Jul-11 Univeral Roddable Gully 110mm Square Tool Station 17.35
19-Jul-11 Pipeweld PVC Cement 500ml Tool Station 6.50
19-Jul-11 Pipe Clip 40mm White Tool Station 0.58
19-Jul-11 Solvent Weld Straight Coupling 40mm White Tool Station 0.64
19-Jul-11 Solvent Weld Bend 135° 40mm White Tool Station 1.28
19-Jul-11 Branch 92.5° Triple Grey Tool Station 11.08
19-Jul-11 Shallow Inspection Chamber Cover Plastic Tool Station 18.33
19-Jul-11 Shallow Inspection Chamber & Riser 110mm 600mm Tool Station 29.44
19-Jul-11 Pipe Coupling Socket 110mm Double Tool Station 6.76
19-Jul-11 Double Socket Bend 110mm 30° Tool Station 14.26
19-Jul-11 Double Socket Bend 110mm 45° Tool Station 14.26
19-Jul-11 Double Socket Bend 110mm 15° Tool Station 14.26
19-Jul-11 Double Socket Bend 110mm 87.5° Tool Station 7.13
19-Jul-11 Equal Junction 110mm 45° Triple Tool Station 10.20
19-Jul-11 Underground Pipe 110mm 6m 3M Tool Station 16.50
29-Jul-11 Labour John 50.00
1-Aug-11 Labour John 50.00
2-Aug-11 Labour John 50.00
3-Aug-11 Labour John 50.00
4-Aug-11 Labour John 50.00
5-Aug-11 Labour John 50.00
8-Aug-11 Labour John 50.00
9-Aug-11 Labour + materials John Smith 178.00
16-Aug-11 Hanson Hampton Rural Blend Bricks Jewson 772.15
16-Aug-11 Thermalite Blocks Jewson 232.00
16-Aug-11 Portland Cement (White) Jewson 62.50
16-Aug-11 Building Sand (1t) Jewson 50.00
20-Aug-11 Labour Steve 80.00
20-Aug-11 Skip (4 yard) C R Hales Limited 84.00
27-Aug-11 Labour Steve Eagle 80.00
22-Aug-11 Masonry joist hangers 150/50 Smith Bros 54.60
22-Aug-11 Wall starter kits Smith Bros 38.35
22-Aug-11 Floor joists 47/150 (3m lengths) Smith Bros 171.29
22-Aug-11 Polythene damp proof course (100mm x 30m) Smith Bros 12.96
29-Aug-11 Access Bend 92.5 Grey Tool Station 15.64
29-Aug-11 Double Socket Bend 110mm 87.5° Tool Station 7.13
29-Aug-11 Pipe Clip 40mm White Tool Station 0.58
29-Aug-11 Sockaway Container 110x300mm Tool Station 24.85
29-Aug-11 Washing Machine Trap 76mm Seal 40mm Each Tool Station 3.68
29-Aug-11 Equal Junction 110mm 87.5 Triple Tool Station 20.40
29-Aug-11 Express Delivery Tool Station 5.00
31-Aug-11 Labour + materials John Smith 90.00
1-Sep-11 Labour John 50.00
3-Sep-11 Labour Steve 80.00
10-Sep-11 Labour Steve 80.00
15-Sep-11 100mm cavity slab insulation (10 sheets) Wickes 59.98
17-Sep-11 Labour Bungle 30.00
18-Sep-11 Toilet, basin, tap, cistern etc Bathstore 407.00
24-Sep-11 Labour Steve 80.00
1-Oct-11 Labour Steve 80.00
8-Oct-11 Labour Steve 60.00
11-Oct-11 Masonry Joist Hangars 225 x 50 Tool Station 55.04
11-Oct-11 C16 Joists 5.1 x 47 x 225 Smith Bros 243.81
11-Oct-11 Diminishing Firings 5.1 x 47 x 75-5 Smith Bros 108.76
11-Oct-11 Catnic CG90/100 1650mm Lintel Condell Limited 64.19
11-Oct-11 Isover Cavity 1200x455x100 12 pack (6.55m2) Condell Limited 28.89
11-Oct-11 Bulk Sand Condell Limited 43.65
15-Oct-11 Labour Steve 60.00
22-Oct-11 Labour Tom 50.00
17-Oct-11 Closed coupling for toilet Travis Perkins 5.72
21-Oct-11 Copper stop end/Sink fittings Grahams 4.80
21-Oct-11 2" x 2" 2.4m timber Wickes 11.37
21-Oct-11 Basin fixings Wickes 2.61
26-Oct-11 14mm x 94mm x 2.4 Cladding Wickes 55.44

[dirty boy]

Estimates of what I think we'll need to finish

• Insulation roof £800 (pir board with 6mm ply attached)
• Insulation floor £400
• Lintels £170
• Coping stones £300
• Window/Doors £1800
• Flat roof £1500
• Electrics £500
• Plumbing £200 (just a couple of rads probably manage with an Uncle)
• Plasterboard/Plastering £300
• Oak floor £1400
• Oak door and bits (internal - where white external one is currently) £400
• Wood burner and fitting £1500 (I have a HETAS mate)

I'd say £10,000 will get me a nice room.

All in for circa £16k by mucking in myself?

£533m2

[mk1fan]

A budget of £70,000.00 would be sufficient to build a reasonable spec extension including fees and assuming there are no site specific issues (conservation area, poor ground conditions, complicated party wall matters).

If you're prepared to do the works yourself - as shown - you can save considerable money. However, I'd keep this fact quiet at sale time. I rarely see 'DIY' work of a competant standard.

[dirty boy]

mk1fan said:

A budget of £70,000.00 would be sufficient to build a reasonable spec extension including fees and assuming there are no site specific issues (conservation area, poor ground conditions, complicated party wall matters).

If you're prepared to do the works yourself - as shown - you can save considerable money. However, I'd keep this fact quiet at sale time. I rarely see 'DIY' work of a competant standard.

Spotted anything on mine?

To be fair, mine's not DIY, it's a "beg, borrow & steal"

Builder is a mate
Plumber is a mate
Carpenter is best mate's dad
Ground worker is a retired neighbour

But sometimes I do wonder about how things are done, and whether it's right, hence I ask so many questions on here.

Also, aren't building regs there for the very reason you mention?

Our building inspector has been brilliant, offering help and ideas on how to overcome certain things, in particular with the drainage issues we had.

[thinfourth2]

100% certain of no party wall issues

[dave_s13]

DIY is often better than pro. Given most pro trades don't give a fook.

[anonymous-user]

dave_s13 said:

DIY is often better than pro. Given most pro trades don't give a fook.

Agreed, the only advantage of a pro is certification (if req'd) and you can go to work in the morning, come home and stuffs been done while you're out. BUT you'll still look at what they did while you were out and wish you'd done it yourself.
Mike

[dirty boy]

thinfourth2 said:

100% certain of no party wall issues

We had to write to both neighbours about digging within a certain distance of their walls regarding that.

Although my attached neighbour never said anything!

[andy43]

thinfourth2 said:

It is hardcored and gravelled and is currently where i park the unimog

One of the cooler quotes I've read on PH
'Shall we take the Aston dahling' sounds very mundane in comparison.

[blindswelledrat]

Muncher said:

dave_s13 said:

Unless you're doing a big chunk of the work yourself, that is what it'll cost, or thereabouts.

We will be and have a lot of contacts meaning for a good chunk of it we won't be paying "normal" prices.

Even then, a significant portion of the cost is labour, and people don't (or shouldn't) do 'mates rates' for thier own manpower in something like that.

[mk1fan]

dirty boy said:

Also, aren't building regs there for the very reason you mention?

No.

[mk1fan]

dirty boy said:

Although my attached neighbour never said anything!

So a dispute [under the Act] automatically arrises. I hope the neighbour remains ignorant.