A roof window brings in light from above, where a wall window cannot reach. How much depends on size, position and pitch. Here is what we think about when planning one in a post-war house.
A roof window lets in daylight from the sky, which is brighter than light through a side window. On a post-war semi in Lawrence Weston with a loft room, a bungalow with a dark middle or a landing without a window, the effect can be large. How large depends on a handful of practical choices.
Why roof light is stronger
A window in the roof faces the open sky. Light comes in at a higher angle, reaches deeper into the room and is less blocked by neighbouring houses, fences and trees. A small roof window can often match a bigger one in a wall. That is why they are popular for loft conversions, landings and rooms that otherwise rely on one narrow side window.
Size and number
A larger window admits more light, but the room, rafter spacing and roof structure set a limit. Two smaller windows can light a room more evenly than one big one, particularly in a long loft. Rafters may need trimming and doubling up around the opening, so the choice affects the structure as well as the brightness.
- Larger glass area means more light
- Two windows spread light more evenly
- Rafter spacing affects the size possible
- Position sets what you actually see
Position on the slope
A window high on the slope looks up at the sky and floods the room with light. A lower one gives more of a view and lets you see the garden or street, but it brings in less brightness at the centre of the room. Orientation matters as well. South-facing windows get more sun, while north-facing windows give soft, steady daylight.
Pitch, lining and finish
A steeper roof gives more vertical glass and more direct light, while a shallower pitch tilts the window towards the sky. The lining around the opening makes a difference too. Pale, angled linings carry light into the room, whereas deep dark ones soak it up. Insulation and vapour control around the opening are done at the same time so the room stays comfortable.
Light and heat
More glass means more sun in summer and more heat loss in winter. Blinds, glazing choice and ventilation all help to balance this. On exposed ground, a window that opens easily and closes tightly is worth thinking about. We discuss how you use the room before recommending size and position, and advise on any checks that may be needed before work starts.
A quick sketch of the room, with furniture marked, helps us place the window where the light is most useful. We can then explain the structural work involved, so the result looks right, works from the first day and fits within what the roof structure can take.
Frequently Asked Questions
Will one roof window be enough for a loft room?
For a small room, often yes. For a long or deep loft, two windows give better spread. We look at the space, the roof structure and your plans for the room, and suggest what makes sense.
Do roof windows make a room hotter?
They can in strong sun, especially facing south. Blinds on the inside, a suitable glazing choice and the ability to open the window for airflow all help. We talk through shading when we plan the position.
Can I add a window to a bungalow roof?
Often yes. Bungalow lofts and dark central rooms benefit a good deal. The roof structure and covering need checking, and the opening is framed properly. We assess the roof first and explain what is possible.
Talk to our team about VELUX and roof window installation in Lawrence Weston
Every roof is different — the fastest way to get an accurate answer is a quick chat with our team.