Roofing materials
Roofing Materials - Weatherproofing overview
When it comes to weatherproofing, the most important part of a roofing system is the topmost layer. This is the visible surface we see when looking at the roof of a building, which is designed to protect the structure from the elements. It’s not only protection that’s important but also the appearance of such materials, as there’s nothing worse than having to look at an ugly roof!
We’ve put together five of the most popular roofing materials used that are both good for weatherproofing but also aesthetically pleasing (when done right).
Clay Tile
Clay tiles were most popular before the widespread use of slate. There are the earlier half round (split pipe efectively) and later flatter interlocking types. The most popular colour is the traditional red terra cotta.
Rows overlap, and the top is waterproofed with ridge tiles.
Concrete Tile
Popular & widespread, these are much cheaper than clay or slate. Available in many colour variants. Like any tile they have a minimum slope requirement. Used below this the top surface degrades faster due to freze-thaw cycles, exposing bare concrete covered with biofilm.
Sometimes concrete tiles have been fitted to originally slated roofs, which were never designed to carry the greater weight. Visibly sagging roofs are a warning flag, failing timber is another cause.
Thatch
This attractive alternative to solid roofing has become a symbol of countryside cottages not only in the UK. It’s the process of layering plant stalks on top of each other to create a weatherproof roof with good insulation. It’s an ancient method of roofing and still is popular in countries which lack resources or funds for hard roofing. The plants used can include rushes, reed and straw, life expectancy varies fairly widely depending on the material.
Maintenance cost is high, a complete rethatch is needed at some point, thatchers are in short supply, thatch is a fire risk, extra electrical precautions such as using MICC cable are wise, and expect high insurance premiums. You will pay for the charm. Thatch is rarely seen on new builds due to the cost & safety issues.
Most thatched roof coverings have been replaced with tile. These are easily spotted, as thatch requires a much steeper roof pitch than any hard roof covering.
Felt Roof
Membrane roofing or felt is mainly used for flat roofs & sheds. It's very light compared to clay tiles or slate, and on flat roofs is sealed across the surface keeping water out. It’s a popular choice for large commercial buildings with flat roofs and also domestic premises. Many older terraced homes have a kitchen or bathroom at the rear with a flat membrane roof. New builds also incorporate it on garages and parts of the home that have only one level.
There are various types of membrane materials from the cheapest bitumen & rag to modified bitumen with synthetic fibre, EPDM synthetic rubber etc.
Felt is the shortest lived of domestic roofing options, and failure tends to rot the supporting timber deck. It's easily holed by walking on it. Never tread on felt topped with stones.
Slate
Slate tiles are completely flat as they are split from blocks of quarried slate. Slate can be expensive. It's natural, fireproof and very low maintenance, it naturally puts up with the elements. Good quality slate has a very long life span, cheap types not so much. It's attractive to look at. It is fragile, load needs to be spread when climbing on the roof. Installion is not complex, but bodgers have made mistakes like fitting narrow slates where there is sideways water movement.
Old slate roofs can appear ok to the nonexpert, yet require a lot of work or complete replacement. Fake slates don't last as well and may contain asbestos.
Shingle
Wood shingles are uncommon on housing, and only occasionally seen on outbuildings. The tiles are split wood, and life expectancy depends on the wood species.
Asphalt Shingles are a cheap roofing option most popular in America. The base material is fiberglass or organic. Added materials can include ceramic granules and vitrified brick, which adds to the colour. They perform well against moisture, sunlight and strong winds, but have limited life.
The original article was written by: our friends at www.topseal.co.uk