A T-shaped roof is a roof form in which two gable roofs meet at right angles, giving the roof a T-shape when viewed from above. The T-shaped roof is created when an extension or wing is placed at right angles to the main building. The two roofs intersect at a valley gutter or valley rafter.
Identification
- The roof has the shape of a T when seen from above
- At the intersection of the two roofs there is a valley gutter (internal gutter) or valley rafter
- The T-shaped roof has more roof surfaces than a simple gable roof
Variants
| Variant | Description |
|---|---|
| **T-shaped roof** | One extension at right angles to the main building |
| **L-shaped roof** | Extension at a corner, forming an L |
| **Cross roof** | Two roofs intersect fully (cross shape) |
| **H-shaped roof** | Two parallel buildings connected by a cross wing |
Valley gutter: the critical point
The intersection of the two roofs is the most vulnerable part. This is where all the rainwater from two roof surfaces comes together. The valley gutter must:
- Be sufficiently wide and deep to drain large volumes of water
- Be finished weathertight with lead, zinc or EPDM
- Be checked regularly for leaf build-up and blockages
- Have adequate fall towards the roof gutter
T-shaped roof in renovation
When adding an extension at right angles to an existing house, a T-shaped roof is often the result. Key considerations:
- The ridge height of the extension is usually lower than the main roof
- The junction with the existing roof must be made fully weathertight
- Check whether planning permission is required
Related terms
- Gable roof
- Cross roof
- Valley gutter
- Valley rafter
- Roof gutter
- Fall