The short answer
Check the roof structure, the height and the way out. A trussed roof needs structural work, a room needs a safe escape route, and any roof window must meet the thermal limit. Building control approval is needed, and the covering outside has to stay watertight around every new opening.
Houses on Covingham Park have loft space that families have turned into bedrooms and offices for years. A conversion is a building project in its own right, and the roof is where much of it happens, so it is worth knowing the questions before a builder is chosen.
Q1.1How is the roof built?
The first question is how the roof is built. A trussed roof uses factory-made triangles that carry the load through thin timbers, and cutting into them needs engineered steel or replacement members. A cut roof, framed on site, is more forgiving. Our page on cut and trussed roofs explains the difference. Once the structure is settled, the tile or slate around each opening has to be cut and flashed so that it stays dry.
Q1.2What do the escape and glazing rules need?
Approved Document B sets a 4.5 m line: for a room within it, the new room needs an escape window or a route onto a protected stairway, and higher storeys follow separate provisions. Approved Document L Table 4.2 limits a new roof window to 1.4 W/m²K, with an alternative route through a minimum of Window Energy Rating Band B. Building control checks these points, and Swindon Borough Council runs its own team.
Q1.3Does a roof window need planning permission?
Whether a window or dormer needs planning permission depends on where the house stands and what has been built already, so we send you to the council or to our roof window planning page before anything is ordered.
Our skylights hub covers the fitting, the flashing kits and the typical costs of a roof window, and the survey photographs your own roof before the quote is written.
If you already have drawings from an architect or a designer, send them with your enquiry. We read them against the real roof, since a drawing cannot show the condition of the rafters or the sag in an old ridge, and we tell you where the two disagree.