Loft conversion cost UK: why the four types are four different builds

How loft conversion cost uk works

1. Settle whether it is permitted development. A great many loft conversion are permitted development, which means no planning application, but the limits on depth, height, materials and how much of the plot is already built on are specific and a designer should read them against your own house before anybody prices anything.
2. Get drawings and a structural design. Existing and proposed drawings, then a structural engineer's calculations for whatever is being opened up or carried. On a loft conversion this is a small share of the total and it is what turns an idea into something three builders can price identically.
3. Serve the party wall notices in time. Work on or near a shared wall, or excavation within three or six metres of a neighbour's foundations, engages the Party Wall etc. Act and the notice periods are set in months rather than weeks. Serving late is the commonest reason a start date slips.
4. Price it against a specification, not a sketch. Ask each builder to price the same written specification, with provisional sums shown as provisional sums. Two quotes that differ by a third almost always differ in what is included: the kitchen, the flooring, the decoration and the drainage diversion are the usual absentees.
5. Agree stages, retention and building control. A staged payment schedule against completed work, a small retention until sign-off, and a clear statement of who is notifying building control. The completion certificate is what a future buyer's solicitor will ask for.

Insurance and paperwork

Common questions

What is the cheapest loft conversion UK houses can have?

A rooflight conversion, because it leaves the roof shape alone and adds no external structure. It is only an option where there is already enough head height, which is why the survey that measures it is the first thing worth paying for.

Does a loft conversion add value?

It usually adds usable floor area, and a bedroom with a compliant escape route and a building control certificate is worth more than a room described as a loft space. That certificate is the difference a valuer and a solicitor both look for.

How long does a loft conversion take?

Typically several weeks on site once drawings, approvals and party wall notices are in place, and those preliminaries take longer than owners expect. Budget the paperwork time separately from the build time.

How much is a loft conversion UK-wide?

There is no single figure, because the four common types are four different builds. A rooflight conversion changes no structure outside the roof, a dormer builds a box out of the slope, a hip to gable rebuilds one end wall and a mansard reconstructs the roof almost entirely, and each adds work the one below it did not have.

Registered contractors by region

• Registered roofers in the East Midlands postcode area
• Registered roofers in the East of England postcode area
• Registered roofers in the London postcode area
• Registered roofers in the North East postcode area
• Registered roofers in the North West postcode area
• Registered roofers in the Scotland postcode area
• Registered roofers in the South East postcode area
• Registered roofers in the South West postcode area
• Registered roofers in the Wales postcode area
• Registered roofers in the West Midlands postcode area
• Registered roofers in the Yorkshire and The Humber postcode area