More About: Flashing and Valleys

Last week, we dropped an article about roof valleys. This week, we want to bring you more information about roof valleys! As your local Cambridge roofing firm – we want to give you a large database of roofing information whenever you need it!

This topic seems to get searched about a lot on Google and we want to write about what people are looking for! So here’s a concise piece about roof valleys!

What are roof valleys? 

Roof valleys are the area of a roof where two points meet to create a valley between them. 

It’s really that simple guys. Just think of a gap being created between where two parts of a roof meet. Usually, houses are obscurely, not like a basic shape. As such, different parts of the roof meet at different angles and create chasms between the adjoining sections. 

How do you protect roof valleys?

We use flashing to protect our roof valleys. Obviously, we need a way to stop these gaps between our roofs being subject to the elements. The chasm type gap left between adjoining parts of the roof make for a nice little gap for water to collect. If you aren’t careful, your valley can turn into a disaster. Hopefully you’re fully aware of how vulnerable a roof can be if leaks occur and aren’t taken care of! 

Flashing is essentially sheet metal. It’s laid out over the valley in order to steer rainwater away from the gap to protect your roof. 

What is roof flashing made from?

Flashing is commonly made from lead or copper. Both are extremely durable materials against the elements. Many classical buildings, like the Chartres Cathedral, use copper. Both materials are superior for adding extra protection to your roof. 

For domestic roofs, much more lead was used than copper as it is more affordable and oxidises less. Flashing is also used around chimneys to protect the valley where they create seams and joints.

Are there more precautions to protect my roof valleys?

Yes! You can get step flashing, or soakers, to act as an extra precaution. It’s necessary, because getting water in your valley could be disastrous. Soakers go underneath the roof and wall shingles. That means you can’t see them, but these are the kind of measures we’ll install at your roof if necessary. 

I have a butterfly Roof… What do I do? 

Butterfly roofs look like two panels connected to each other, but both slope downwards towards their point of connections. The idea with butterfly roofs was that water would run down to the valley between the two parts and pour away. These were known as “London Roofs” as they were popular in the capital during the Georgian and Victorian era. The style of roof was made famous by William Krisel and Dan Palmer in the 1950s when they created nearly 2,000 houses. 

If you have a butterfly roof, you are likely ok and won’t need flashing. The valley is aggressive, so if you need any extra TLC, you can call us out.  

Box gutters

A box gutter could be used between a valley. Box gutters are placed between parallel roofs or at the junction of a roof and a parapet wall. 

They are different to valley gutters and valley flashings as these happen at non-parallel interaction of roof surfaces – normally at right angled corners.