There are several ways of going approaching your project and the one you select depends on your property, your tastes and the regulations. Here’s a quick guide to the basic types.
This is the simplest and most inexpensive conversion. Velux roof windows conversions simply add some roof windows front and rear of the existing roof slopes, leaving the external roof shape with no extensions. Installing a new staircase, which is manufactured by specialised joiners, in off-site workshops. most projects would have a least one bedroom and a shower room. There is seldom any need to apply for planning permission unless your property is in a conservation area
Dormer conversions are by far the most common type of conversion. Normally built without the need for planning permission via permitted development on house, on flats and maisonettes planning permission would be required
This means very little change to the look of the property at the front and a magnificent outlook to the rear – maybe including French window and Juliette balcony
If your property has a rear addition like so many London Victorian and Edwardian houses, an L-shaped dormer can have space for two new rooms and a shower room.There is seldom any need for planning permission
Mansards are typically associated with London town houses with “butterfly” type roofs, but more often extended at the rear of mid terrace victorian properties
The rear roof slopes at 70 degrees and smaller dormer windows are inset so there is very little compromise to the quality of the space inside, the party wall each side of the mansard are built up in London stock bricks
You also have the option of going for the L shape mansard, if you have a rear addition to your property adding a further extension over this section of the roof slope are the rear
This is the solution if your roof has a sloping hip-end instead of a gable end – the type of house that was more commonly build after the Edwardian period.
The good new from a planning point of view is that your are allowed the sme 40cu mtrs roof space as your mid-terrace neighbours, but your end wall will need to be built up and your gable extended to meet it.
Once you have done this you may be able to add an extra window to the end of your new room and will also have the same options as with the other types – Velux, Dormer or Mansard.