Loft Conversion Estimator/Price Guide




All About Estimating the Cost of a Loft Conversion…


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Loft Conversion Estimator/Price Guide


Terraced House Loft Conversion



25m² existing first floor area

(A totally empty loft converted to one bedroom only, utilising all available loft space. This basic conversion accounts for…….

All professional fees

A straight stair (over existing or from a bedroom) with top landing and door.

2 velux windows

A wooden floor (no steel required)

Insulation all round including the hidden loft space

A ceiling hung from the rafters, with no horizontal area

Two low stud walls with no access hatches

Plastering all round (inc. both party walls)

Skirtings, architraving and door furniture

1 radiator

4 electrical sockets

4 recessed lights with 2 switches

Smoke alarms and heat alarm to loft, first and ground floors

Rubbish removal

£24,000 (for larger areas add £500 per square metre)



Hipped roof Semi Detached House Loft Conversion



45m² existing first floor area

Same basic conversion as the terraced house…….£31,000

(for different areas add/remove £500 per square metre)



Hipped roof Detached House Loft Conversion


65m² existing first floor area

Same basic conversion as the terraced house……
£35,500

(for different areas add/remove £500 per square metre)



Hipped roof Semi Detached Bungalow Loft Conversion


50m² existing floor area

Same basic conversion as the terraced house, minus smoke alarms, landing and top door…£31,500

(for different areas add/remove £500 per square metre)


Hipped roof Detached Bungalow Loft Conversion


80m² existing floor area

Same basic conversion as the terraced house, minus smoke alarms, landing and top door…£38,000

(for different areas add/remove £500 per square metre)



Additional Work / Extras


(The following additional work is to be added to each of the 5 basic prices already given, so select the type of house, adjust the area price, then add the options below as required).


Remove internal roof trusses and fit steel beams etc. to support the remaining structure…….
£10,000

Fit a pitched roof, dormer window on the hipped side roof pitch to accommodate a new landing. (Planning won’t usually allow a
flat roofed dormer on the hipped, side roof pitch).

1.5 metres wide…..
£3,500

3 metres wide …..
£6,500

Completely remove the hipped end and construct a rendered gable end…….
£8,000

(this will also require planning permission)

Move the existing water and central heating tanks to the side of the loft with an access hatch ………
£1650

Remove the water tanks altogether……..
£400

(this doesn’t include redesigning the heating and domestic water supply systems)

Fit 2 storage access hatches……..
£200

Fit a small “collared” ceiling……..
£600

Fit a full ceiling where possible…….
£1050

Fit a single winder stair………
£100

Fit a double winder stair……….
£200

Create a corridor for a stair fitted in a bedroom……..
£650

Fit an extra (normal) velux window……..
£600

Fit a flat roof dormer (probably to the rear elevation)

1.5 metres wide…..
£3,000

3 metres wide…….
£6,000

Fit steel beams to support the floor…….
£2,500

Fit a steel beam to support the ridge…….
£2,500

Fit a basic en suite bathroom (shower, basin, toilet, fan, basic tiling)……
£4,500

Fit a second bedroom……….
£1200

Fat a extra radiator………
£350

Fit extra electrical sockets…….
£50 each

Fit extra recessed lights……….
£40 each

Paint all round (emulsion to walls, gloss to door, banisters etc)……….
£1000

Fit carpets including the stairs…….
£550


A Guide To The Process of Converting a Loft