Flat roofs are incredibly common in the architectural world. Unlike its counterpart, the gable roof, flat roofs rest completely horizontally (or very near to it) on top of a housing structure and are most often constructed on industrial or commercial buildings, but that doesn’t mean it’s not a good option for you and your home. The slope of a flat roof is minimal when compared to most residential homes and they’re not made from the traditional roofing materials like asphalt shingles or concrete roof tiles. That’s because these cause seams in the roofing, which will almost definitely leak on a flat roof. That means the main goal of a flat roof is to create a barrier that is impervious to water.
To achieve this, these roofs are made from tar and gravel, which we see in the Built-Up roof, PVC membranes, which are comprised of a single layer of thermoplastic material, or Modified Bitumen, a multi-ply roofing material. Each of these materials comes with their own pros and cons.
There are generally five or six different alleys you can go down when choosing your roof materials, but we’re going to go over just the four most common.
The first is on the top of the list as one of the most popular flat roofing materials–PVC. PVC membrane is a single-ply thermoplastic material that is substantially durable and are heat-welded to form a watertight bond. Most PVC membranes (mainly the white ones) are energy efficient because they reflect the heat of the sun instead of absorbing it like a black material would. It can be installed in two ways–as a mechanically attached system using hidden metal plates to fasted the concealed and overlapping parts of the membrane to the deck of the roof, or as a fully-adhered (or glued) system and both come with a lifetime warranty. This type of roof has a lifespan of 15-30 years, so you can rest assured knowing it will last.
Our next material is EPDM, which is commonly known as the rubber roof. EPDM is attractive to many homeowners because it comes at a much lower price than PVC. It has a good reputation around durability, but they do have their faults. Because it’s treated with adhesives to build, it makes the seams vulnerable over time. That means that this roofing material is one of the more maintenance-intensive flat roof options. It also has the propensity to absorb heat, and that might end up driving up your utility bills. They do, however, last a good 10-15 years.
Another kind of material is called TPO. TPO is a single-ply roofing membrane that chemically joins rubber, ethylene, and propylene with a few filler materials. This roofing material is growing in popularity because of its energy-efficient nature and lifespan of 7-20 years. This material is considered the best of both PVC and EPDM because it’s closer to a rubber roof in price, but has the welded, durable seams of PVC membranes. This new technology, though, requires experienced contractors, which might come at a disadvantage to you.
The last roof material to mention is the silicon spray on coating. The greatest pro to this type of material is that you can do without seams, which is something that comes with membrane roofs. They also have a lifespan of up to 20 years. The downside, however, is that this is one of the most expensive roofing procedures.
Each roofing type has a different cost to it depending on the material, installation method, and complexity of the job.
PVC is on the higher end of the scale, ranging from 320-460 MYR per square meter to install. This is because many contractors will only mechanically attach the roof, which adds to labor costs. And in addition to the membrane itself, an installation board needs to be installed first in order to help with energy costs.
EPDM, on the other hand, is cheaper than PVC. They average from 185-320 MYR per square meter. When installing this roof, manufacturers try to avoid seams by using sizeable pieces of membrane that can reach 15 meters wide by 60 meters in length. These big pieces are great for avoiding possible leaks, but the rolls are also difficult to manage during installation. These membranes are put on like a giant sticker, but it needs to be done slowly and with precision in order to avoid bubbles.
With TPO flat roofs, insulation boards are first fastened to the roof substrate. TPO comes in rolls and can be mechanically attached to the insulation boards or put in with a self-adhesive. This option is slightly costlier than EPDM, averaging between 230-370 MYR per square meter.
Silicone spray is about as costly as PVC, as material costs drive installation prices. They average at about up to 275-460 MYR per square meter, or sometimes more.
Built-up roofing lasts 15-20 years with an average cost of 230-320 MYR per square meter.
The installation process can seem long and arduous, but when in the right hands, it can be done relatively quickly and efficiently. You need to decide which type of flat roof you want to install. Each one requires periodic inspection and maintenance. You then need to choose your materials. Think about the surface area of your roof, as this will determine if a single or multi-ply system would be better for you.
- The first step in this process is the roof preparation. Although it is called a flat roof, there is actually a small incline (at least 1 centimeter per meter) to keep water from pooling on top. A foam underlayment is usually used for commercial buildings, but on smaller roofs you can use long wedges nailed to the joists to create the incline.
- Sheath with plywood and leave a 1cm gap at all joints to allow for expansion and contraction.
- Screw down the underlayment of sheet rubber roofing material. This provides a soft and protective base layer for the rubber. Stagger the joints and fit the pieces tightly together.
- Next, create beveled corners. This keeps water from pooling at the inside corners.
- Before putting down the rubber, sweep the roof to remove any debris that could puncture it. Cut a piece of EPDM rubber as large as the roof with some room to spare to dry-fit the roof.
- Now we glue down the rubber. Spread your glue over the exposed section of board and on the rubber you will lay over it. Once the glue is on both surfaces, it will bond instantly. Once dry, carefully spread the rubber over the boards and smoothing out the rubber so that there are no air bubbles.
- Finally, finish the edges by overlapping the EPDM and using rubber adhesive to set it firmly in place.
To keep vertical sections from peeing off, screw in metal brackets. Then nail down a custom lead-coating.