Membranes made of rubber or PVC are popular options for commercial roofing. Membrane roofing is more suitable than shingles and other types of roofing for flat roofs where water ponding is an issue. The membranes are attached to each other in different ways depending on the material used. Some might use seam tape with adhesive while others are heat welded. Methods of attaching the membrane to the roof vary too. Here are three popular methods of installing membrane for commercial roofing.
1. Mechanically Fastened
With this method, the membranes are screwed to the roof. This is the most popular way to attach membrane roofing since they are easy and quick to install. The roofer places small round plates along the edges of a membrane and then inserts screws in the middle of the plates. The screws pass through the membrane, insulation board, and roof deck to hold the roofing securely in place. The screws are placed along the seams and ends of the membranes.
2. Fully Adhered
Fully adhered membranes are applied to the roof with a layer of tacky adhesive. First, insulation boards are put down and screwed to the roof deck. Then the adhesive is rolled on and the membrane is attached to the adhesive using a roller to make a tight seal. An advantage of using fully adhered membranes is that they are more wind resistant than mechanically attached membranes.
Membranes that are mechanically attached stay secure along the edges, but the middle of the membrane might flutter in the wind since it isn't adhered. Ask your commercial roofing contractor if wind resistance is an important consideration for your building and if fully adhered membranes are necessary.
The drawbacks to fully adhered installation are that it is time-consuming and more expensive and the odor of adhesive might be bothersome to your employees and clients. Plus, the adhesive needs to be applied in a specific temperature range, while other methods of installation can be applied in any outdoor temperature.
A ballasted membrane roof is one where the membrane is held down with rocks. This is similar to built-up roofing, except the rocks are larger and applied in a thicker layer so they can hold the membrane down securely as the only form of attachment. Putting down rocks is a quick way to attach membrane roofing. All that's needed is to roll out the membranes and then spread around the rocks. The roofer might use mechanical fasteners in a few strategic places, but the rocks are the primary way the membranes are held in place.
One reason to choose this form of commercial roofing installation is for the sake of appearance. You can buy different types and colors of rocks so your roof is attractive when seen from above in a taller building. Plus, the rocks provide fire protection and they shield against UV rays, so they help the membrane last a long time.