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info@howellandsons.co.uk
Instant Labour & Materials Estimate
Single-storey rear extension, 5.6 m wide by 4.0 m deep externally, forming a kitchen-diner of about 18.5 m². Cavity walls in facing brick to match the house, a flat roof with a roof lantern, aluminium bi-fold doors across the rear and a side window. A new 4.2 m opening is formed in the existing rear wall with a steel beam over, to open the extension into the house.
Cost summary
Each price includes the labour and materials for that stage, plus its share of site management, welfare, skips, contingency and our overheads.
| Stage | Labour | Materials | Total |
|---|---|---|---|
| Working at Height Precautions | £0.00 | £1,291.11 | £1,291.11 |
| Enabling works | £2,821.41 | £638.76 | £3,460.17 |
| Foundations | £3,232.25 | £2,516.41 | £5,748.66 |
| Drainage | £2,742.76 | £1,724.95 | £4,467.71 |
| Foundation masonry | £703.11 | £916.61 | £1,619.72 |
| Ground floor | £2,862.22 | £3,478.48 | £6,340.70 |
| Brickworks | £5,017.98 | £6,864.63 | £11,882.61 |
| Windows & external doors | £555.32 | £1,512.72 | £2,068.04 |
| Structural works | £1,367.84 | £1,194.10 | £2,561.94 |
| Gutters & rainwater pipes | £715.51 | £436.68 | £1,152.19 |
| Joinery 1st fix | £1,059.50 | £847.14 | £1,906.64 |
| Joinery 2nd & final fix | £961.74 | £1,095.24 | £2,056.98 |
| Flat roofs | £4,295.08 | £8,961.26 | £13,256.34 |
| Insulation | £305.61 | £384.31 | £689.92 |
| Plastering | £5,445.92 | £1,541.50 | £6,987.42 |
| Electrical | £4,615.94 | £1,403.25 | £6,019.19 |
| Heating | £2,005.66 | £1,170.92 | £3,176.58 |
| Plumbing first fix | £1,875.64 | £399.37 | £2,275.01 |
| Painting & decorating | £3,370.40 | £279.93 | £3,650.33 |
| Sundries, fixings & fasteners | £0.00 | £359.84 | £359.84 |
| Total excluding VAT | £80,971.10 | ||
| VAT (20%) | £16,194.22 | ||
| Total including VAT | £97,165.32 |
This is an estimate based on your drawings, not a quote or a fixed price. The real cost depends on a site visit, ground conditions, the structural engineer's details, building control requirements and the finishes you choose. It doesn't include professional fees, planning or building control charges, or anything listed under "no allowance for" below. If you go ahead with Howell & Sons, the fee for this estimate is deducted from your build.
Assumptions we have made
- Foundations 600 x 1000 mm; deeper foundations would cost more.
- Steel beam over the new opening sized at about 4.6 m long, to be confirmed by a structural engineer.
- Flat roof as a warm deck with a mid-range roof lantern.
- Mid-range aluminium bi-fold doors.
We have made no allowance for
- Structural engineer's calculations and drawings
- Drainage layout and any work to existing drains
- Kitchen units, appliances and worktops
- Floor finishes such as tiles or wood flooring
- Planning, building control and party wall fees
Howell & Sons Construction Ltd. Registered in England and Wales, company no. 11270942. Registered office: The Barn, Musgrave Farm, Horningsea Road, Fen Ditton, Cambridge CB5 8SZ.