Allison--would be very interested in your take on the GHG issues of foams, which have received lots of smart commentary recently. To highlight a few: architect Jesse Thompson's comments on Tom's Good vs Bad post on Energy Circle, the very thorough piece by Alex Wilson on Green Building Advisor and Michael Anschel's cautionary diatribe on Remodeling.
How Much Does Spray Foam Insulation Cost
Thoroughly clean the roof surface. Roofs collect oils from asphalt, chimneys, and cars plus lots of dirt and dust. Coatings don’t stick well to any of these. We recommend cleaning with an inexpensive solution of TSP or TSP Substitute in a bucket of water (follow label instructions). Use a broom to scrub ponding areas and areas of peeling coatings. Work a section at a time and hose off the dirty water. Sweep away puddles to promote drying. Do not allow wash water to dry on walls, furniture, windows, and visible surfaces.
Clean and free the roof surface of any debris and then dry the surface using a cloth. If you happen to have a current coating on the surface, check for adhesion. Consider removing loose coating, repairing, cleaning and then checking the area. Remember to use Energy Guard without thinning it because it is sold ready for use. Containers should not be left open except for a short period of time. You must also ensure that you check for any existing coating adhesion before opening Energy Guard. For application, you will require a brush preferably a bristle brush (synthetic) or a short nap roller. You can also use a good airless sprayer with a 0.031 or 0.027 tip to apply the coatings at (3000 psi/1gpm). You will also need water for cleaning up when you are done.
KARNAK manufactures a complete line of sustainable roof coatings, sealants, and waterproofing solutions certified to comply with UL, FM, CRRC, ENERGY STAR®, Dade County, Title 24, and Florida’s HVZ building code. Our ENERGY STAR-labeled coatings can help buildings obtain LEED points. With four factories and seven warehouses across the U.S., KARNAK’s dedicated sales and customer service team will deliver the products you need in less time than it takes our quick-dry 535 Envirolastic to cure.
Part of that guidance will be explaining that interior, two component foam is applied with the professional using specific personal protective equipment (high-pressure foam is installed while using a respirator, for example). It is encouraged that professionals explain clearly to customers that this equipment, coupled with certain work and engineering practices, including ventilation, is used to minimize exposures to the chemicals used to make SPF during the job.
There is a significant price difference when it comes to using foam insulation to insulate a new versus older home. Spraying insulation inside a newly constructed home is easier because the installation company can ensure the insulation will work effectively and design it for optimum defense against sound, heat transfer and utility costs. Installing spray foam in older homes that contain existing insulation can cost additional time and money -- it is not usually recommended as compared to weatherization or an energy aduit.
In general, cantilevered steel beams are a nightmare. If part of the steel beam is in contact with exterior temperatures, then it's best if the interior portion of the steel beam is covered on all sides with insulation. This is generally impossible (because the interior portion of the cantilevered beam generally supports a load, meaning that you can't wrap the steel beam in insulation on all sides).
Spray foam insulation is typically priced by volume, meaning your cost will depend on how much material you need to use to insulate your space, although other factors may influence price as well. In most cases, the cost of spray foam insulation is more than worth it, as it's a once and done upgrade that will not only provide energy savings in your home, but also improve your home's overall comfort.