Wooden Structure Build Costs

Scope of Works

• Site survey & design confirmation – measure footprint, check ground levels, confirm load paths and any planning constraints.

• Set‑out & foundations – mark post positions; install concrete pads, ground screws or treated timber footings.

• Fabricate & erect frame – cut C24 or CLS structural timber to size, assemble posts, beams and rafters with weather‑sealed fixings.

• Roofing/cladding – fit ply deck, EPDM or felt roof; add feather‑edge boards, shiplap or composite cladding as specified.

• Weather‑proof & treat – apply breathable membrane, drip flashings and two coats of UV‑resistant wood preservative or paint.

• Doors, glazing & trim – hang stable door or bi‑folds, fit toughened glass, add fascias, gutters and insect mesh vents.

• Clean‑up & hand‑over – tidy site, remove waste, supply maintenance schedule and structural warranty.
  

Typical Cost (inc. VAT)

Time on Site

• Simple pergola (3 × 3 m): 2 – 3 days.

• Timber shed with felt roof (4 × 2 m): 3 – 5 days.

• Insulated garden room (≤20 m²): 7 – 10 working days including first‑fix electrics.

• Factors extending duration: wet ground delaying foundations, bespoke glazing lead‑times, scaffold erection, or additional service trenching.
  

Questions to Ask Your Trade

1. What grade and treatment class of timber will you use, and is it FSC‑certified?

2. How will the structure be anchored—ground screws, pads or slab?

3. Do the works need planning permission or Building Regs sign‑off, and who handles it?

4. What warranty is offered on structural frame, roof covering and paint finish?

5. Will you run electrical/data cabling and arrange Part P certification?

6. Is waste disposal & final landscaping reinstatement included in the quote?

7. How will you protect adjacent plants/fences from sawdust, preservative overspray or machinery?
   

How to Avoid Surprises 

• Access & parking: ensure 2 m clear gate width and reserve van space close to the build area.

• Ground‑condition check: soft, sloping or made‑up ground may need deeper pads—budget for extra concrete.

• Confirm timber moisture & acclimatisation: store packs off the ground and covered for 48 h before assembly.

• Weather plan: agree a wet‑weather schedule; preservative and roof membranes need dry windows to cure.

• Plan future services: duct power, water or data before the deck/floor goes down.

• Ventilation gap: maintain 50 mm air space below cladding to prevent rot.

• Written fixed‑price contract: list design drawings, spec, payment stages and VAT to keep the project within the £3,500 – £12,000 bracket.