SPRAY FOAM; PART OF THE INSULATION PACKAGE


    For the past two weeks our crew has been “very carefully” insulating the newly added interior steel studded walls of the church. If you are interested in catching up on this project, please go to www.alltechgreenchurch.ca

    Last week the small areas needing spray foam were completed; behind the electrical plugs and along the floor juncture, corners and any cracks in the old plaster behind the new walls, for example. Since it’s not recommended to apply spray foam too thick on one pass, in many instances, John or Spar had to go back to apply a second layer. When using the spray cans, we aim for a 2” thickness for each pass, allowing for cure time before another layer is added. While this is time consuming, it is a crucial step.

    When the internal wall system was added onto the original walls, because of the angle of the roof we ended up with a 40 foot long space between the two walls at the top. We looked at trying to fit Roxul into that space, but quickly realized that this would be difficult too impossible arriving at a precise fit. Having used a product called “Tiger Foam” in the past with good success, I decided to try it here. This Canadian company manufactures and sells directly to consumers requiring spray foam kits for areas too large for the can method, but not large enough to bring in a commercial spray foam company. 

    Tiger Foam is sold as a complete package kit; foam, tanks, lines, spray gun and extra tips. They have two kinds of closed foam; fast rise and slow rise; each one with a distinctive area of use and application. For the difficult to access areas in the church, the fast rise foam kit will suit nicely. With a quick cure of five minutes, it allows the crew to go back over an area while working from a ten foot scaffold, reducing the amount of time needed to move the scaffold. The drawback is that, due to its fast cure time, they must start and continue or, having stopped, will have to change tips. With a number of areas to spray, that could become inconvenient, so pre-planning will be important. On the plus side again, Tiger foam contains no CFC’s, VOC’s or formaldehyde and is advertised as environmentally friendly. The R factor of 6.2 - 7.4 suits the level of insulation needed, while limiting the thickness to 3 - 4 inches; perfect for our openings. Once the foam is sprayed in, we will have insulation and air barrier, all in one application. For more information, go to www.tigerfoam.ca

     While Tiger Foam has its place, spraying the entire crawl space will be another matter and we intend to bring in a professional spray foam company when we arrive at that stage.

     There are two main types of commercial spray foam insulation on the market; open cell, half pound spray foam and closed cell, two pound spray foam. Open cell foam forms a spongy layer over the substrate. Once it is sprayed on, it creates a blanket of air cells that fill all the “nooks and crannies” of the area being sprayed. This material is vapor permeable; it does not absorb water, however, it can hold moisture in the small air cell pockets and can take some time to dry out. Covering with a drywall surface is, therefore, recommended. Two pound, closed cell foam or medium density foam cures to a hard surface and, with its low air permeability, qualifies as an air barrier. There is an off gassing with most closed cell foams and application in layers no thicker than 2 inches is recommended. At this thickness, on average, an approximate R value ranging from R10-12, based upon the manufacturers advertised values, will be reached.

     If you decide to bring in a professional spray company there are a couple of things to note. The material has a shelf life. The barrels are date labelled and out of date material should not be used. There are documented cases where the off gassing has caused health issues, so make sure the home is well ventilated during application. Our crews are not allowed into a home that is being sprayed until the next day. That said, when sprayed to the manufacturers specifications, spray foam is typically non-toxic after it has cured. There are several advantages to the commercial process. Along with insulation and air barrier in one package, it doesn’t allow mold to take hold, and most deflect water on the surface. While the open cell has a greater vapor permeable capacity than closed, the closed cell foams also have a low vapor permeance, all-be-it very little.  

     In keeping with the sustainable theme of the church, we look for “green” products and have selected Polar foam PF 7300 to insulate the crawl space. This closed cell foam is advertised to have one of the highest air barrier performances on the market. It is also well documented that all closed cell foam will make a building stronger and stiffer. Anything we can do that will add to the integrity of this gorgeous heritage building is considered. Spraying an old stone foundation takes some effort and the stone surface must be stable or any spray foam will fail. Some time ago, I selected Jeff Kleinlagel and his crew at Kingston Spray Foam Insulation to do our work as they apply Polar Foam. Jeff also has considerable experience in heritage spray applications. When we sat down to discuss this project, stability of the foundation was Jeff’s major concern and, consequently, another inspection around the crawl space was done. The areas where our mason needs to do some repoint and patch work before Jeff returns were marked off. While spray foam is the answer, if the substrate is not stable, any foam will fail.

     With the insulation complete, the crew will be working to put up the 6 ml plastic air barrier and the necessary strapping in preparation for the v-groove pine panelling, which will be the subject of the next column on the church reno.