4 Factors to Consider When Roofing With Concrete Tiles

Concrete tiles are a popular roofing alternative to clay tiles. They are ideal if you want the classic tile roofing without incurring the cost of clay tiles, which is significantly higher than other roofing systems. The distinctive appearance of tile can improve the curb appeal hence the resale value of a home, and you can expect your concrete-tiled roof to last at least 50 years and even longer depending on the quality of installation and material. This article discusses some factors to consider when thinking about concrete tiles for initial or replacement roofing in your home.

1. Clay tile comparison 

Clay tile roofs can cost at least 30 percent more than concrete tiles, but that price premium does have its advantages. For instance, clay tiles can last up to 100 years, although there are buildings, mostly in Europe, that have had sturdy roofs for centuries.

Traditionally fired clay doesn't degrade on exposure to elements, and it doesn't rot or burn either. Conversely, concrete can be degraded by elemental exposure and things like acid from bird droppings and water retention from debris buildup. As such, concrete tiles will require more hands-on maintenance, including regular cleaning and keeping birds off the roof.

In addition, while concrete tiles can be coloured using integral pigment covering the entire tile, this colouring fades on exposure to elements, unlike clay tiles which fade very slightly and often not at all.

2. Roof weight

Both clay and concrete tiles are heavier than other roofing systems. Consult with an engineer before installing a concrete tile roof to avoid collapse. This is especially important during roof replacement, because some structures may need wall and roofing frame reinforcement to carry the weight of a tiled roof. However, manufacturers today are also building lighter concrete tiles which replace sand with lightweight aggregates such as expanded shale.

3. Tile shapes

Concrete tiles are available in three conventional profiles: villa tiles (have a lower profile and a double-S shape), Spanish S tiles (also called mission S-tiles) and flat tiles (resemble slates or wood shakes). However, today you can get many different shapes depending on the aesthetic finish you want. Your supplier should provide trim tiles to match the shape you choose. In most cases, you'll use two types: one for the ridges and another for the rest of the roof.

4. Roofing slope

Most manufacturers recommend that the slope should not be below 3/12 to 5/12, although you can go as low as 2.5/12 with specialised waterproofing underlayment. The slope or pitch is the minimum angulation a roof should have and still remain watertight. Different manufacturers have specific minimums according to the tiling type. For lower slopes, the installation method used should minimise the use of fasteners, which penetrate the underlayment and hence increase chances of leakage.