If you are interested in the benefits of slate roofing, such as a 100+ year lifespan, excellent energy efficiency, and minimal maintenance, you may be wondering what the ideal pitch for a slate roof is – and if it can be used in your home.
What Is Roof Pitch? Understanding The Basics
Roof pitch is a measurement used in home construction to measure the slope of a roof, based on the height of the roof, the rafter pitch, and rafter length. Basically, it’s a measure of how steep the roof is.
The higher the roof pitch angle, the steeper the roof. A flat roof, for example, would theoretically have a pitch of 0° – although in reality, it will have a slight pitch of several degrees to help drain water away.
In contrast, a 20° pitch will create a more angled roof. This assists in drainage, and also affects the visual appearance of the home. The steeper the pitch, the steeper the angle of the roof will be. A pitch of about 20° to 30° is relatively common in Australia.
In snowier areas, though, roof pitches are often steeper, since this helps with snow buildup. Steeper roofs with a pitch of 40° or more will shed snow more easily, and help drain away the water that melts away from ice and snowpack – preserving the roof.
Slate Roofs Typically Need A Minimum Roof Pitch Of 20 Degrees
Natural slate roofing is typically used in homes with at least 20-degree pitches. It’s not a great option for roofs with very low pitches. This is because of the construction of the tiles used in roof tiling and slating.
This is because a very shallow roof could lead to a higher risk of leaks. Modern, double-lap slate roofs are durable, and use “head lap” installation techniques to overlap multiple slate tiles and reduce the risk of leakage – basically, the tiles are overlapped in a way that helps prevent rain and moisture from entering. Slate is impermeable, so when rain hits a slate roof tile, it will roll down the slate, across the next tile, and so on – until it reaches the gutter and is drained away from the roof completely.
However, this is only the case when the water is able to drain away properly. If the roof is nearly flat or has a very low pitch angle, the water won’t be able to drain away properly. It’s more likely to “sit” on the tile, and find its way into the small cracks between the tiles. Over time, this can cause premature weathering and damage to the slate tiles, as well as a higher risk of water damage and leaks in your home.
Because of this, the general recommendation for slate is a 20° pitch angle. There are some circumstances in which slate roofs can have a minimum pitch as low as 17.5°, but this depends on the type of slate being used, the size of the lap, and some other factors.
If you have a roof that’s lower than 20° in pitch but are interested in slate, an expert slate contractor from NSW Slate Roofing can help you determine if slate roofing is suitable for your home.
Is There A Maximum Roof Pitch For Slate Roofs?
Slate roofs can be used for any roof with a minimum pitch of at least 20° – even extremely steep Victorian-style roofs that may be up to 40° to 45° or more. However, installing slate tiles on a steep roof does require some additional safety precautions, specialised equipment, and additional fasteners, so it will typically be more expensive to install slate on extremely steep roofs.
Contact NSW Slate Roofing To See If Slate Roofing Is Right For You!
Not sure what the pitch of your roof is, or if slate is appropriate for your home in Sydney and the surrounding areas? NSW Slate Roof is here to help. Contact us now to get a free consultation. Our master slaters can help you learn everything you need to know about slate, roof pitch, and whether or not slate tiles are a good choice for your home.