Unless a cover board is used, spray foam cannot be installed over a TPO roof. The shortfall with a TPO roof is that it is not completely adhered to the roof deck as the material is just heat-welded at the seams and not attached to the substrate at all.
However, Norris Spray foam has had many successful projects which resulted in spray foam roofing over a TPO roof. We start by making an inspection of the roof under the TPO layer and make any repairs or augmentations needed. Then, we use a cover board that we fully adhere to the roof substrate which can accept the spray foam roofing material.
What is a TPO roof?
TPO is one of a few different types of rubber, usually a blend of polypropylene and ethylene-propylene rubber. These single ply roofing systems are a dependable and energy efficient roofing system that lowers your home’s overall construction costs. TPO roofing systems are quite common in both home and commercial roofs.
Single-ply membranes are synthetic as well as rubber in their makeup. To adhere these membranes to a flat roof, they are either fastened mechanically, ballasted to a roof, or affixed to the insulation that forms a protective layer on a flat roof surface.
Single-ply is a commonly known type of commercial material. However, you might not know that there are two types of single-ply membranes made to suit both the budgets and the building needs of commercial operations.
In scientific jargon, TPO translates to Thermoplastic Polyolefin. It is categorized as a layer of a single-ply membrane composed of synthetic components along with a fabric reinforcing scrim that stabilizes and strengthens the membrane for improved and increased performance. It consists of a smattering of different rubber types that are usually a combination of polypropylene and ethylene-propylene rubber.
TPO has gained considerable use with commercial roofing systems, particularly in covering flat roofs. It’s doubly sought after for its natural reflective ability to deflect ultraviolet waves (UV) while conserving energy and saving on utility costs.
The manufacturer fabricates the membranes themselves in sheet form, and they measure in widths of 10, 12, and 20 feet. Once cut, rolled, and assembled, the manufacturer distributes the sheets to the facility that requests and purchases the materials for commercial roofing purposes.
Fire-Rated, Class A – Both TPO and EPDM membranes are Class A fire-resistant. During the production process, the manufacturer adds fire retardant chemicals to the composition of the material.
Reflective and Penetrable – Most TPO is usually white and extremely reflective.
Like all synthetic roofing options, no two companies produce the same formula of TPO. Instead, they alter it just enough to create their own brand. All of it results in a membrane material, between 40 and 100 millimeters thick that gets attached to a roof deck.
TPO is known as a single-ply application, meaning one sheet is sufficient to achieve the benefits. It competes each year directly with EPDM, and PVC membranes (PVC is similar in application methodology to TPO) with some of the same benefits, but with each system having its unique pros and cons.
Reroofing with spray foam is also possible on these other commercial roofing system types.
Built Up Roofing Systems | EPDM | Metal Roofs | Modified Bitumen Roofing System | Single Ply | TPO