All About your Roof Valleys

A roof valley is the gutter-like valley that runs between two sloped sections of roof. That is, where two sloping sections of roof meet, they need a way for water to escape. That’s where a roof valley comes in. Naturally, roof valleys undergo a fair amount of wear over time, given they’re designated sections that allow water and debris to escape and not build-up on a roof. Just like gutters, they can wear, leak, and get blocked up. Roof valley repairs are a common situation where you might need professional roofing contractors in Nottingham or your area to help with the problem. Particularly on older roofs, roof valleys can be weak spots and prone to damage.


Roof valleys can be made of different types of material. Older roof valleys were typically galvanised. That is, coated in a layer of zinc to prevent the iron/steel from rusting. Inevitably, over time, small cracks appear in the protective layer, and as soon as water gets inside, rust begins to form. Rust causes structural weakness and continues to propagate the problem as it spreads. Small instances of rust can be repaired if caught quickly, but once the structural integrity or a valley is compromised, it’ll likely need a replacement.


Roof valleys are typically made of lead, concrete or fibreglass. Aluminium is now growing in popularity, as a lightweight and rust-resistant alternative to older iron/steel valleys. No doubt as technology continues to improve we’ll see valleys with incredibly long lifespans that resist the elements incredibly well. Lead is excellent and is very popular in the UK, but naturally, it needs to be handled by a professional as it is a poisonous material.


Rust usually forms at localised points when the protective coating gets compromised. If this works its way deeper, a leak can begin. If there are any signs such as a discoloured or bulging ceiling, or the ceiling starts dripping, you’ll need to get in contact with a professional as soon as possible. Leaks that develop from roof valleys tend to develop slowly, rather than suddenly.

Valleys function similarly to gutters, meaning they’re in danger of getting blogged by debris. If you have tall trees near your roof, you’ll need to do more frequent visual inspections to make sure your valleys are clear. A clogged valley acts like a damn, allowing the water that would otherwise flow to the ground to pool behind the blockage. Water that sits there adds weight and can flow into the roof cavity if it finds a gap. It creates a corrosive environment that can eat away at the structure. Blockages need to be cleared as soon as possible to prevent damage occurring.


Repairs vary depending on the exact problem. It might be, for example, that a leak has developed where the cement holding the tiles surrounding the valley has crumbled. Then, the valley can be left and simply the cement can be replaced and the tiles reset. For more severe problems, especially problems with the valley itself, a full replacement may well be needed.


A full valley replacement is a big job, involving a significant amount of work and cost compared with a simple repair. The tiles surrounding the valley will need to be removed as well as the underfelt, and possibly some timber section below. These materials will all be replaced with the new valley in mind, so it sits flush in the right place. The removed tiles can be replaced with new cement.

A replacement can be done within half a day with two workers, but of course, it depends on the size of the section so there is some variance.

At best, roof valleys can last 20 years. It’s highly dependent on the materials used, the quality of the installation, the location of the house, the weather, and so on. Small leaks that can be quickly repaired don’t necessarily mean your valleys are in desperate need of replacing, but we can always advise on your best course of action. If you have a problem with your roof valley, don’t hesitate to get in contact and we can come and visit and get a free quote sorted.