Roof slopes vary from relatively steep, to flat. Well almost flat, because every roof must slope slightly to allow water to drain. We discuss the pros and cons of pitched and flat roofs, and the things to know when purchasing or constructing an outbuilding or home

Which Type of Roof is Best?

Pitched roofs are commonest on residential buildings, because their appearance can add style and grace, and attic conversions can increase living space too. But both types of roofs are popular in residential outbuildings

However, almost-flat roofs are more likely on commercial structures, because they are handy places to locate air-conditioning and refrigeration plant, and more recently solar panels too.

Pros and Cons of Materials for Flat and Pitched Roofs

Asphalt shingles, as well as clay and cement tiles are popular choices for pitched roofs in Calgary. They are relatively expensive, but can generally withstand the worst  our weather can bring.

However, they do need a minimum pitch to avoid moisture flowing in between the joints, and of course the steeper the roof the more shingles or tiles you need.

Almost flat roofs, on the other hand are generally made of precast concrete components, covered over with an applied waterproofing surface. It pays to use some of the labour savings to afford decent quality waterproofing in this case.

Leaks Are More of a Challenge with Flat Roofs

The pros and cons of pitched and flat roofs are fairly balanced at this stage. However, it’s a roof’s job to lead rainwater and melt away, and this is far easier with a pitched roof that has gravity on its side.

Almost flat roofs are more prone to leaks from pooled water finding a way through cracks. Therefore, they need more regular inspection and maintenance than pitched ones do.

The Long Term Cost Can be the Clincher

Flat roofs cost less per square foot of coverage, than pitched ones do to construct. However, the cost of maintenance can eat away at this benefit making them more expensive in the long run.

This can suit the cash-flow model of commercial buildings, where tenants contribute overheads. However, in the case of a residential home it may be better to pay for a pitched roof up front, and have lower recurring maintenance costs.

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Parts of a Roof: K.D. Schroeder BY CC 3.0