Portland PVC Roofing
Commercial flat roofs in Portland have changed over the last decade, away from hot tar and asphalt roofs. It used to be that we would get on the roof with some extremely hot molten tar and a mop and spread the tar around the roof to create a sealed roofing surface. Layer upon layer of tar and membrane were used to build up the roof surface until we had a completely sealed and impermeable surface of roofing. This is how hot tar roofs got the names like “built up roof” or “hot mop roofs”. Ultimately, someone thought that a different surface installation would be a better idea. So their idea was to come up with a torch applied membrane. And as you can probably already guess, that led to other problems, such as burned down buildings, raised insurance rates, and unhappy building owners. Currently many laws of been passed to prevent this new torch applied membrane from being installed in their state. Enter the new product: PVC membrane
PVC roofing membranes are a solid surface factory produced membrane that is approximately 1/8 inch thick, comes in rolls up to 8 feet wide by 100 feet long. These roll membranes cover a huge area in a single pass. And because it covers so much area and is only 1/8 inch thick, the weight that this roof brings with it is negligible. 1000 square foot area of roofing done with PVC membrane would weigh approximately 500 pounds. By comparison, a hot not or build up a roof could weigh up to 5000 pounds for the same size area.
One distinct advantage to using a PVC membrane for your roof is that while there is some sealing to be done manually on certain areas of the roof as it’s completed, the majority of the roof is factory produced in a controlled atmosphere. This means that the manufacturer can offer extended product warranties for the product and installation. The product is available in 50, at 60, and 80 mil. thicknesses. The manufacturers’ warranties are typically 10 years, 15 years and up, respectively. PVC is available in many different colors and patterns.
PVC Roofing Installation
Installation of PVC membranes can be done in a variety of ways, but typically is installed with screws and fasteners that ultimately end up buried underneath the PVC membrane. There are no exposed fasteners on the top of the PVC roofs when the project is completed. Another way that the membrane is installed is by gluing the membrane down, better known as “fully adhered”. This method of installation is preferable if you’re going to be using the PVC as a walking membrane, or if you’re in a high wind area, such as the coastal areas. Regardless of the installation methods, PVC is a very strong roofing membrane with very light weight characteristics.
Parapet Wall
Additional items on commercial flat roofs include wall attachments, and drainage. Provisions need to be made for the roofing to be adhered up any walls that it’s touching, and then counter-flashed by a medium such as siding, flashings, etc. There should never be a cut edge membrane that is exposed against a vertical surface. On top of the wall, there should be a cap metal, used to divert the rain water that hits on top of the wall. Walls such as these, also known as “parapet walls” need to have a metal cap to protect the wall from the elements. Exposed wood on top of a wall will act to absorb water readily, so a metal cap must always be used on top of the wall to protect the water that hits it.
PVC Tapered Insulation
Additional items on commercial flat roofs include wall attachments, and drainage. Provisions need to be made for the roofing to be adhered up any walls that it’s touching, and then counter-flashed by a medium such as siding, flashings, etc. There should never be a cut edge membrane that is exposed against a vertical surface. On top of the wall, there should be a cap metal, used to divert the rain water that hits on top of the wall. Walls such as these, also known as “parapet walls” need to have a metal cap to protect the wall from the elements. Exposed wood on top of a wall will act to absorb water readily, so a metal cap must always be used on top of the wall to protect the water that hits it.
PVC Roofing Drains
When planning for your roof drain, there are two types of roof drains that are typical. It’s important to know where you’re down spout goes into the ground so that you know how to plan for your roof drain. One way is to run a horizontal box straight through the parapet wall, better known as a “thru wall scupper”.
The other drain method is to use a commercial drain that ties directly into the drainage pipe in the middle of the roof deck. Both methods of drainage are excellent, and if installed correctly should lead to years of no problems.
PVC Roof Planning
A commercial flat roof in Portland requires a huge amount of pre-planning. All the items listed above need to be designed into the roof, and time must be given to design and order all of the appropriate parts for your commercial roof. PVC membrane has worked out for us for decades, and we have grown to endorse the product highly. Give us a call to show you the difference Dial One Roofing commercial roofing contractors can make for you and your commercial structure.