Common Defects – Tiled Roof Coverings

This is where we summarise the typical defects affecting tiled roof coverings.

Moss

By far the most common issue with pitched roof coverings, and in particular tiled coverings, is the accumulation of moss.

The most obvious issue with moss relates to another element, rainwater fittings, which become blocked as the moss builds up and becomes detached from the tiles.

However, before it becomes detached it can build up to such an extent that it causes rainwater to back up and penetrate though the tiled covering and this is where the integrity of the sarking felt is critical.

A build up of moss can also damage the surface of the tiles over time. Moss accumulates when a roof covering remains wet for an extended period which generally means that it is in shade for much of the day but the pitch of the roof is also a factor – rainwater runs off the surface of shallow pitched roof more slowly. Once moss starts to accumulate, it acts like a sponge, keeping the covering wet for even longer and allowing the moss growth to accelerate. In freezing weather, these damp conditions and the weight of the moss may cause the surface of the tile to delaminate. Concrete tiles are more resistant than clay but are also susceptible.

Removing moss really is just a case of scraping it off as carefully as possible but, due to the difficulty of access, it’s generally done by professionals. If a biocide is applied it should keep it at bay for a few years but it will eventually return. Trimming back overhanging trees is also recommended as it will allow the covering to dry more quickly following rain and reduce the amount of organic matter in the air.

If you live in the Cambridgeshire of north Essex area and would like a quote for an RICS Home Survey, please contact us for a quote on 01799 543532 or via email.