Most people that are interested in converting their flat roof to a pitched roof are simply tired of dealing with leaks, repairs and other issues. Tar and gravel, and other asphalt based roofing, were the most popular roofing material for flat roofs until recently. Even today, there are roofing companies that recommend installing asphalt (aka Built Up Roof). These types of roofs dry and crack and lead to headaches even before the material warranty period ends. Additionally, any poorly installed flat roofing system requires constant upkeep and repair. As a consequence, many people look into converting their low sloped roof to a pitched roof, commonly called a Roof Conversion.
For those of you who are in this frustrating position, let’s take a look at all of your options, as well as the pros and cons of a conversion. Roofing manufacturers have introduced reliable flat roof membranes, such as TPO and EPDM, which have grown in both credibility and popularity over the last decade. While it may seem that shingles will solve all of your problems, the fact is that TPO and EPDM membranes can be just as water tight as a pitched roof.
It is important to find a roofing contractor that can identify the right kind of membrane and be able to install it properly. This is important, as the dependability of a roof is determined by the quality of material and the skill level with which it was installed. If you can find a qualified contractor to install a dependable membrane on your home or business, it can cost 3 to 4 times less than a roof conversion. White roofing membranes can also be extremely energy efficient, resulting in energy savings over time.
If you are considering converting your roof in order to raise the value of your home, keep in mind that the value of your home will only increase about half of the cost of the conversion. As a result, if you are considering selling your home within the next 7-10 years, converting your roof may not be worth the required time and money.
However, there are some viable reasons to convert to a pitched roof. Probably the best reason I have come across is a situation I ran into a few days ago. The owner was concerned that his flat roof’s support system was not structurally sound. He could hear the rafters creaking under the weight of recent snowfall. That creaking is usually the result of fasteners coming apart a little bit at a time. Nails and screws will creak as the structures wood members. If the fasteners back out, or if wood dries and shrinks, it could cause a dangerous and destructive situation.
A pitched roof conversion, done properly, will distribute weight to the bearing walls of the structure. In the previous case, a conversion would help his structurally unsound roof to become dependable long term.
Some other pros to converting your flat roof to pitched include:
You simply like the look of shingles. If money isn’t a concern, the perceived aesthetic value of a pitched system can be enough of a reason in and of itself.
A roof conversion results in easier and more efficient insulation. It is more economical to insulate a pitched roof at R40 than it is to try and insulate a flat roof with even an R19. (Insulating a flat cavity usually requires removing sheet rock or sheeting.) You can also insulate above the roof deck and below the waterproofing system with rigid insulation, but once again this is fairly expensive.
Vapor drive, which causes moisture to form on the underside of a roof system, won’t occur with a pitched roof as easily because you can create an efficient pattern of air flow. (If the humidity in the home is equal to the humidity outside, vapor drive will not be an issue.)
You may be able to create more storage space or even an added room in the cavity between the existing flat and newly pitched roof.
Pitched roofs have about a 40% longer life than flat roofs. They last 25-50 years, while a flat roof membrane will last about 15-20 years.
Flat roofs are about 10-20% more expensive to install than a pitched roof (after the conversion). This is because the membrane is more expensive to manufacture, as well as the need for more specialized labor.
In the end, it is really just up to you and your individual situation to decide whether a roof conversion is right for you and your home.