Flat Roofing

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Flat felt roof from above
Felt Roof

Felt Roof

There are various coverings that are frequently used for flat roofing. The oldest and worst performing are bitumen based felts. There are varying grades of type of felt. These became very popular in the 1980s. This was due to the very cheap material cost of rolls of bitumen felts. These tended to have a life expectancy of around 10-15 years. Better synthetic felts are now available. These can have a life expectancy of up to 25 years. This shorter life span is due to the damaging UV rays causing the bitumen felts to shrink. They then crack and the upper layers are compromised. Water gets into the cracks/ fissures. It freezes casing the cracks to open further.

Bristol

Felt is still commonly used in Bristol. Even in newer work. The more modern materials are often shunned. In favour of these older materials that are easier to install. Or the trades may have more experience with felts. In our experience the decking and supports are often one of the larger issues. Air flow beneath is key to keeping the deck rot free. The design of the flat roof and pitch is very important and this is down to a carpenter. Rather than the roof covering installer.              

Reactive vs proactive

Flat roofs are often not visible, they are out of sight and out of mind. Especially with a loft conversion. Little is often done with them until they fail. As a result of the short life span of flat felt roofing. Insurers often have specific exclusions. These remove cover with a felt roof over 10 years old. This is problematic when a modern synthetic felt roof fails. However, the exclusion still stands.

People often ignore ponding on flat felt roofing. When a roof starts to pond, the timer has started on its demise. The water in pools freezes. It expands and puts stress on the felt around the edge of the pond.

The trades perspective

Felt used to be melted into place. However now there are safer, self-adhesive ones available. These are the cheapest to install a felt roof is the easiest and cheapest method of flat roofing. The built-up layers mean a fault in one layer does not necessarily mean it will fail. Workmanship is still key to a good felt flat roof installation.