Flat roofs are hard to replace
Some observers suggest it’s harder to replace a flat roof than a traditional pitched shingle roof because of the labor required to remove its layers (especially on older flat roofs). But now, flat roofs often are constructed with fewer layers because of improved waterproofing technology. This could mean flat roofs may not raise the same red flags they used to among prospective homeowners who may want to replace or remodel the roof once they move in.
Prone to water damage or leakage
Many of the potential problems a flat roof may attract – such as water pooling, leakage and resulting rot or damage – are due to poor installation or poor maintenance. Pay careful attention to the roof at the construction phase and throughout its lifecycle to help prevent these problems in the first place.
Parts Of A Flat Roof
To an untrained eye, one flat roof looks very much like another (especially from the ground level!) but, in fact, there are several different flat roof systems to choose from.
At the most basic level, a flat roof consists of three basic components:
Depending on the materials selected, these might be combined into a single product, but all these functions should still be there.
Other Flat Roof Components
Underneath the basics, flat roofs are usually constructed with a ceiling, nailed to joists which support a deck (usually wood in residential construction), a vapor barrier, insulation and a roof board. From there, the flat roof system you choose will determine the materials you apply.
Consider geography, budget and use for the roof to determine the best option.
Warm vs. Cold Roofs
A note to consider before construction: if insulation is installed below the flat roof deck this is called a “cold” roof. Generally, roofers discourage this method for cold climates because it can promote condensation and requires ventilating the roof, which may be difficult to do in small or tight spaces. On the other hand, a “warm” (or hot) roof is one where the insulation is installed above the deck. This situation is suited for cold weather climates. (See more details here).
Here is a diagram of a typical warm roof: