Spray polyurethane foam, or SPF, is the main type of 2-part, closed-cell spray foam used by insulation contractors. Large-scale insulation jobs require special equipment as well as safety gear to protect the installer from chemical fumes during installation. When the foam cures and hardens just several minutes after application, it's completely safe for as long as it stays in place.
Liquid Rubber is generally fine when applied in one coat at a 20 mil film (42 sq ft per gallon) thickness and will still withstand extremes. That is the beauty of the EPDM polymer. A second coat would provide insurance where exposures are likely to be very extreme. Radical extremes in temperature where constant surface temperatures reach 250°F or above or -20°F or below. Warning, though, if the second coat is applied at the wrong time, it may create cracking, fissures or bubbling. The second coat should be applied either when the first coat is still tacky or when that first coat has had a chance to fully cure (up to 3 months.) https://youtube.com/v/ggLAUsiuI_o?version=3
I did a LOT of prep before using this product. Cleaned, vacuumed, installed additional insulation etc etc etc. This spray foam was easy to work with, and did it's job as it was supposed to. If you are curious, this kit was purchased because - every "foam insulation company" I contacted either did not call back (due to no interest) OR this was too small of a job. That is why I went DIY on this one, that and: I was advised by one of these companies that they have a minimum $2k job because ... (insert your answer here, but I will choose that everyone needs to eat).
Spray Foam Existing Wall
Porch urns are an excellent way to add seasonal curbside flair. However, tall items such as twigs, birch stems or even pumpkins can sway in the breeze and make a mess of your carefully planned decor. To prevent things from shifting, place your items in the container and spray around them with expanding foam to create a comfy nest that will keep your urns looking great. Place a layer of moss, hay or greenery on top to finish the look. https://www.youtube.com/embed/ggLAUsiuI_o
I don't know if it's common or uncommon, but installing a layer of rigid foam above your roof sheathing in order to interrupt thermal bridging is always a good idea, and is preferable in all respects to a roof assembly without any rigid foam above the sheathing. If you decide to install rigid foam above the roof sheathing, you shouldn't use closed-cell spray foam under the sheathing; either use open-cell spray foam (which is vapor-permeable) or a fluffy insulation like cellulose, mineral wool, or fiberglass (any of which will allow the roof sheathing to dry to the interior).
When looking for a long-term roof solution, compare apples to apples. Liquid EPDM Rubber is a one-coat application. There are no primers needed, and when you begin adding up the cost of other systems that require primers and multiple coats, you are often exceeding the cost of liquid EPDM Rubber and have an inferior sealant on your roof. Why add unnecessary weight to a roof by using multiple-coat systems? Cut your time and labor costs in half with a one-coat system. Liquid EPDM has a very thick honey-like consistency and a slow cure time. One of the biggest benefits of the product. During the cure process, you will see bubbles resembling those created when you cook a pancake. This is the catalyst at work forcing the trapped air to the surface. What you have after the cure is a chemical bond between your roof and the coating. No other coatings produces this result. Other products trap this air making future cracks inevitable as temperatures change or expansion and contraction of the roof occur.