The hardest working part of a roof
Where two roof slopes meet at an internal angle, a valley channels water from both into the gutter. In heavy rain a valley may carry far more water than any other part of the roof, so any weakness is quickly exposed. Houses with extensions, rear returns and bay windows tend to have several.
Types of valley
- Lead-lined valleys, hidden behind the slates or tiles or open as a lead gutter
- Valley gutters between parapets or in the roof of a terraced house
- Glass-reinforced plastic (GRP) valleys and other modern liners
- Tiled or slated valleys in which the tiles are cut and mitred
What goes wrong
Lead can crack through repeated heating and cooling, particularly where sheets are long or fixed too tightly. Debris, moss and leaves can block valleys and cause water to back up under the covering. Cement fillets and mortar bedding that crack let water through, and broken or cut tiles at the valley edge fail. On older properties, previous patch repairs add up over time.
How we repair
We locate the fault and check the timber boards and rafters beneath. A small crack in lead can sometimes be repaired, but where lead is worn or has failed across a section, relining is the more reliable option. Relining means lifting the adjacent slates or tiles, replacing the lining with new lead or a suitable alternative, correctly lapped and laid to falls, and relaying the roof covering. Damaged boards are replaced as needed.
Why valleys in terraces matter
Many terraced houses in Newcastle and North Tyneside have a valley gutter running between two roofs, or between a roof and a parapet. These are often hidden from view, and problems may go unnoticed until stains appear on ceilings. They are linked with parapet issues, see parapet wall rebuilding. Related junction work includes lead flashing replacement and roof timber strengthening.
Roof repairs normally do not need consent, but listed and conservation area buildings may be affected. Check the Planning Portal.
Frequently asked questions
How can I tell if the leak is from the valley?
Stains that appear below a point where two roof slopes meet, or after heavy rain, point to a valley. A roof inspection from height is the best way to confirm it.
Can I clear my own valley?
Only if you can do so safely. Roofs are dangerous to work on, and walking on lead or slates can cause damage. It is usually better to use someone with proper access equipment.
