Q&A Forums

How much quality difference in roofing SPF? Post New Topic | Post Reply

Author Comments
Brad Mix
Posted: Dec 29, 2010 05:56 AM
How much quality difference in roofing SPF?
I am having my roof sprayed with Polyurethane foam. I wanted to know if there is a significant between roofing Polyurethane foam from different manufacturers. I live in Palm Springs where the temperature gets as hot as 120 degrees in the summer. My primary concern is durability, a roof that can withstand extreme heat and expansion & contraction from a 30 degree in daily temperature. Second consideration is the R value, insulation value, but durability is my primary concern.

I wanted to know which manufacturers have the best or highest rated Polyurethane foam roofing products. Is there a significant difference between generic foam products and branded foam products from manufacturers? My same questions apply to roof coatings. Your appreciation and guidance is appreciated.
mason
Posted: Dec 29, 2010 07:51 AM
First to get an education on sprayfoam roofing go to masonknowles.com and download articles on roofing.

Check out this article in particular http://www.buildings.com/ArticleDetails/tabid/3321/ArticleID/2753/Default.aspx

It not only discusses sprayfoam roofing but also gives helpful tips in selecting a SPF roofing contractor.

Next go to sprayfoam.org and download the following technical documents on SPF roofing;
AY 104, Guidelines for New and Remedial SPF Roofing Systems
AY 102, Guideline for Elastomeric Coatings Used in SPF Roofing

These documents will provide the technical information of the physical properties required for the foam and coatings used in SPF roofing

Now as for the manufacturers and their relative quality;

There are many manufacturers of spray polyurethane foam and protective coatings that go over foam. As for the best quality of foam roofing, that is more dependent on the contractor's skill and responsibility than the material. However, you do want a sprayfoam system that has been tested and rated UL 790 class A on non-combustible surfaces and most of the coating suppliers have FM Class I Roofing Covering approvals which take into consideration hail and wind resistance as well as fire tests.

Check out their applicator certification and warranty program. Compare their contractors with other supplier's contractors. Get references from the contractor and supplier and call them! Use my tips to ask the right questions.

You need a nominal 3 lb density foam covered with a protective coating specifically designed for sprayfoam roofing or an aggregate covering with coating used on the perimeter edges and protrusions.

The most common coatings are acrylic, silicone and polyurethane. Any of the 3 can be used in your area. Acrylic coatings tend to be cheaper but you need a high quality acrylic coating designed for your area. There are some generic acrylic roof coatings that are not specifically designed over sprayfoam. You can tell these by the solids content. These coatings have more fillers than resin and will typically be sold in the large hardware stores such as Home Depot or Lowes. The solids content (by volume) typically is less than 50%.

In your area the most common coatings are manufactured by National Coatings, United Coatings, La Polla, Bay Systems NA, BASF, SWD Urethane, Gaco Western and some others.

As for durability, acrylic coatings need a recoat around the 10 to 15 year mark if they are installed at a nominal 25-30 dry film thickness.

The acrylic will erode at around .5 mils per year on average. The sun's uv will age a good coating making it brittle at around the 15 year mark. So you want to recoat before that.

Silicone coatings are more expensive but do not age. They will erode similar to the acrylic coatings so they typically are recoated around the 15 year mark.

Polyurethane coatings can have the greatest variety of physical properties. There main benefit is high tensile strength and chemical resistance. We typically see these coatings more often if a lot of foot traffic is expected or to reduce the damage from impact from hail or flying debris from high winds.

As I mentioned earlier the contractor is the most important decision. Use my tips to find a good one and use their best judgement on the type of system to use for your particular project.

You need to login to reply to this topic. Please click here to login.