Last time I wondered that I found it on the MFR website
did the job I wanted. thought it would expand more than it did
Purchased Last week & used immediately. Maybe just a really bad batch??
Hello AdrianM, Actually, I have the exact situation you have. I have two bay windows so in my basement, there were two areas of cantilevered spaces. The floor joists were on 16" centers (like yours) but I have 2x10 joists (not 2x8's like yours). Mine were about 2' deep as well. First, let's discuss cantenlivers. Most houses and climes would treat this as a space that does not need a vapor barrier. Floors are under negative pressure as warm air rises and leaks out of the top of a house which in turns pulls air in from the bottom of your house (unless your house is uber tight - which from your description is not). Therefore, warm moist air inside does not tend to push into floor areas. Before insulating, take the time inside and outside to caulk and air seal all the bays - all sides, all corners, etc. with a good quality chalk. I have a tough time reaching the very rear and used a flexible stick to get to the far reaches as the chalk gun would not fit/reach all places. Check the board outside. Sometimes they use 1/4" plywood or something even worse. If so, consider skinning over with something better and seal the outside seams as well. How much insulation do you need? You have outside air under your cantilever outdoors and you have a conditioned space above. What do you need to fill that space? Depending what climate zone you are in, you need to insulate up to a particular R-value. For hot-humid or hot-dry, you need R13 (3-1/2" of fiberglass), for mixed humid or mixed dry: R19 (5-1/2" of fiberglass). All others (marine, cold, very cold or subarctic) you need R30 (9-1/2" of fiberglass). I live in marine climate zone so I needed to fill the 2x10 joist completely with fiberglass to achieve R30. If you live in such a zone, then you would need to either use mineral wool batts OR rigid or spray foam to the top of the bay, and fiberglass to the rest equalling R30 since fiberglass alone in a 2x8 bay would not achieve R30 (only R24). However, you were asking about big gap filler. Would it work - yes. However, it would be DIFFICULT to install and fill all gaps. Firstly, the spray cans mix and shoot our a straw under low pressure and will fall or roll down the top or sides, then expand. And this is with you reaching into the bay with limited space or control. It is slow to expand as well. This means you can only do a bit, wait for it to expand and come back and do another layer. If you do it too soon, you will have a mess. If you wait too long, the can may not work. And don't touch it as it is super sticky. In the limited space, you will get this all over you. I would say that this would be a poor way to go. I know - I have tried this before. If you want spray foam, then you would need a spray insulation kit (HD has these). These are true two-part mixing cans under pressure that yields 200 board feet of foam to a certain depth. You could easily fill the entire bay with just 2 or 3 passes in seconds. But this is costly. You would place the wand to the back, press the trigger and withdraw which would uniformly spray and stick to the top of the bay and expand instantly downward. Rigid foam (like the Polyisocyanurate or pink foam boards which HD sells) can be cut to fit. Place on the top of the bay and "glue" in place with spray foam or liquid nails. Fill the remainder with fiberglass or wool. The boards state how much R-value they have per inch so it would be easy to deduce how much foam versus the remaining space filled with fiberglass you would need to equal the desired R-value. Note: fiberglass is hard to get right. You have to cut it accurately (slightly larger than the space and finesse it into the space to fill all voids. Fiberglass is susceptible to water, mold and critters. However, mineral wool has a higher R-value, easier to cut to shape (serrated bread knife), soft enough to squeeze into a bay, is fireproof, critter and mold proof and isn't ruined if it gets wet. If I was building a house today, I would use mineral wool everywhere - no fiberglass at all. It is even a great sound barrier. This is also sold at HD. The spray foam has its uses - small gaps I use chalk, bigger gaps, standard can Great Stuff foam, voids - Big Gap Filler, but for large spaces, I would use insulation or spray kit. Spray kits air seal so you don't have to chalk and such first. However, all other insulation, air seal every nook and cranny first! Hope that helps, Jeff in Seattle
OPEN CELL = take on water, boat becomes a wet log Weight when soaked = no buoyance Sealing in light weight air (or any gas less weight than) = ideal floatation Buddy's old leaking Sunfish (pontoon sailer) filled w/GS to seal from inside now only supports & responds at helm to only ONE person when it used to do well with 2 adults + 2 kids onboard
Typical drainage solution SOP re: The Money Pit radio show First create positive drainage AWAY from basement at grade level, no less than 6" down in 10ft run + leaders (gutter drain pipes, if any) must have extensions that also pour the floods away 6-10ft away from basement Then it might be possible to use this cheap OPEN cell foam instead of proper CLOSED cell foam (ala professional installation) that will in time sponge up water and deteriorate. Perhaps by them your drainage solution outside is working well enough.
OF COURSE not to mention sticking to your flesh FORVER and a day
If you are trying to fill the interior of the tire, this is not the right stuff for you (only for cracks and crevices). Here's what it's designed to do. https://www.homedepot.com/p/GREAT-STUFF-16-oz-Big-Gap-Filler-Insulating-Foam-Sealant-Quick-Stop-Straw-99053938/207050533
Are you saying that you want to use Great Stuff primarily to insulate your outbuilding? Not smart at all. First, it would be terribly expensive. Second, this stuff will expand approximately 3 times it's size. And last, too much of any good thing is bad. I don't know, but I would think a vast concentration of any chemical based component would have some harmful effects. Insulate it using regular methods and then use the Great Stuff to seal cracks and gaps.