How Are Roof Tiles Held in Place?

Roof tiles have been used for thousands of years as a way of keeping buildings dry. But to do their job properly, they need to be held in place. It’s good to know how exactly that works so you can understand why some of your tiles may have slipped away.

In this post, we’ll take a closer look at the different way roof tiles are held in place.

How are the tiles held in place?

The standard way to hold roof tiles in place is with a combination of nails and felt. Modern roofs in the UK usually use one of two types of tiles – plain or interlocking. Depending on which is used this affects how the tiles are laid and held in place.

Plain tiles have to be ‘double-lapped’ which means there are two layers of tile throughout the roof, and at the end laps of the tiles the top tile must overlap the tile two below it. In addition, generally with plain tiles, only every fourth course of tiles is nailed to the roof.

Interlocking or ‘single-lap’ tiles however can be laid as one layer of tile as the tiles have interlocking grooves along the side edges which form tight joints. With these tiles, each tile on specific areas such as the eaves and up verges must be nailed down to secure it, but otherwise nailing can be done in patterns like every second course.

When a roof is tiled, not all of the tiles have to be individually nailed on as mentioned above, and it can be beneficial to have some tiles indirectly supported as this allows for easier swapping of the tiles if necessary later on. If every tile was nailed it makes for a harder repair job in the future.

What about felt?

Roofing felt has become common practice for roofs as it provides a flat, uniform base for the tiles to be placed on. It also adds an extra layer of water protection and a touch more insulation.

That said, roofs don’t have to have felt between the roof and the tiles. This is the case for many houses built before the 1950s, which have simply never had felt. Instead, they used back-pointing (mortar) to hold the tiles in place alongside nails.

Why are my tiles falling off?

The use of back-pointing instead of felt has become more apparent over the last couple of decades as this mortar gradually wears away and leaves tiles slipping out of place. That’s one possible reason for your tiles falling off.

Another common cause of slipping or falling tiles is corrosion of the nails that keep them in place. Over time, nails can become corroded through exposure to the weather. As they corrode, they become weaker which reduces support for the tile.

Alternatively, your roof might have been damaged by the weather. Any loose tiles will be more vulnerable to wind and rain. Unfortunately, this can have a domino effect with other tiles, as the missing one can allow the weather to get to those around it.

Fixing your tiles

If you’re looking to replace missing tiles or fix them back in place, the team at DPR Roofing is on hand to help. With over 30 years’ experience, we can provide dependable roof repairs throughout Leeds and the surrounding areas. Give our team a call on 0113 335 0043 to arrange an inspection.