Loft conversion costs

Loft conversions are generally the most cost effective way of gaining space in an existing house.

Because there is no foundation work, little new walling and not even very much in the way of new roofing, the structural side of the job can be carried out at relatively low cost compared to an extension.

However, the work is often quite labour intensive and slow and this adds to the cost.

Bear in mind that it is difficult to compare with extensions on a unit area basis because some of the converted loft space is less than head height but still usable as storage.

One way to budget for loft conversions is to take the footprint area of the loft (the ceiling area of the storey below) and use this as a multiplier to get a budget figure.

Very simple lofts with rooflights and an easy fit staircase tend to cost around £250/rn2 (making a minimum cost on a terraced house of £10,000).

This figure can double as the shape of the loft becomes more complex: full width dormers, balconies, hipped roofs, plus expensive fittings such as bathrooms will all tend to push the unit area cost up beyond £400/rn2.

A largish loft conversion in a detached 30s house could easily cost upwards of £25,000 - still cheaper than an extension.