More About the Sprayed Polyurethane Foam Roofing

More About the Sprayed Polyurethane Foam Roofing

More About the Sprayed Polyurethane Foam Roofing

Sprayed Polyurethane foam roofing is one of the most popular type of techniques which is used for the roofing.

One of the most sophisticated roofing systems is the Sprayed Polyurethane Foam (SPF) roof. By using the techniques of spray application and combining it with liquid applied roofing methods a combined roof insulation and waterproofing membrane is developed that has been very successful in some applications. SPF systems won’t work for every type of roof but for many roofs it serves excellent purpose. The Polyurethane Foam roof insulation can be manufactured on the roof using a specially designed spray gun that mixes the two chemicals needed to generate a PUF insulation. Applicators walk across the roof deck spraying the liquid which swells on application into the tiny celled foam insulation. Afterward, the same equipment is used to apply a waterproofing coating over the foam, isolating it and protecting it from ultraviolet light and water.

SPF systems are becoming increasingly popular, but are difficult to apply. One of the many problems with SPF systems is poor quality control in the field while the material is being sprayed. If the deck is not properly prepared, to hot or too cold, or if there is moisture in the deck or if it is placed too thick or too thin then the SPF roofing system can have problems. Many facilities have had problems with utilizing sprayed polyurethane foam roofing systems not because the product is poor but because the installation of the product was performed by technicians not familiar with PUF application or by application on a deck that wasn’t suited for or poorly prepared for the SPF system. The same fire class problems with sprayed foam apply as with the PUF foam boards. Application is limited to certain types of decks with various materials. Again, the wrong application of foam and decking can lead to increased insurance costs or could be rejected by code authorities for some occupancies.

Finally, the SPF systems have had to be reformulated to comply with new federal regulations against chlorofluorocarbons (CFCs) which are being heavily taxed to prevent their use because of suspected depletion of the earth’s ozone layers. The industry has been successful in getting new HCFCs approved and they are being used in lieu of the older CFCs. SPF systems have proved useful and have found a certain acceptance within roofing industry markets. SPF roofing systems will see even greater service in the years to come. As discussed with the liquid applied roofing membranes, it is important to apply the Sprayed Polyurethane Foam Roofing so that it drains correctly. Low points and voids will eventually hold water that can penetrate into the insulation and break it down under freeze-thaw cycles. Final coats of waterproofing membrane should be applied in layers to form a final dry film thickness of 30 mils or more. One mil equals 1/100 of an inch.



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