A mansard is the favoured style for many London loft conversions on Victorian or other period properties as a mansard does not ’stand out’ from the roof as much as a dormer loft conversion.
The problem with mansards is that some planners dislike them altogether and many local authorities require you to obtain planning permission for a mansard loft conversion in London even if you have permitted development rights. This is because under permitted development you cannot extend ‘beyond the curtilage’ of your property (i.e. not beyond your legal boundaries).
A mansard will normally involve raising the party wall(s) between you and your neighbour(s) and because the boundary is halfway down the middle of the party wall you are technically extending beyond the curtilage of your property by approximately 4.5″ by raising the whole wall.
We think that this policy is totally counterproductive as it simply encourages owners of properties to opt for large dormers that are often unsympathetic to the character of their home.
We have however had a small victory recently by utilising a ‘loop-hole’ in the law. So long as you and your neighbour(s) both have permitted development rights there is nothing to stop you agreeing with one another to each raise your own half of the party wall at the same time. This way no one is extending beyond the curtilage of their property: you are both merely building on your own side of the boundary (at the same time). Practically the wall will be built by us on behalf of both of you as we would normally do.
This approach allows you to build a mansard (with your neighbour’s consent) without the need to apply for planning approval thereby resulting in an aesthetically pleasing London loft conversion for you and the opportunity for your neighbour to easily extend their own loft in the future.
We have recently tested this approach in one of the London boroughs and, despite some argument with the planners, they eventually accepted that this would indeed be lawful development. A victory for common sense and good building design!
Tags: loft conversions, Planning Permission, utilising loft space
