Been working on a few things at a time but almost done working on the air sealing and pre-insulation work in the addition. I took some time away from working due to vacation and a pretty hot few weeks in there.

I decided to pickup a mini-diy spray foam kit to finish my crawl space before it gets cold.

I found something pretty interesting on the spray foam front this morning. I saw this machine before but I did not wish to spend $3500 - $5000 for the machine. I did a little more research and found that the machine is simply, the gun that comes with the DIY kit, two tanks that are similar to the DIY tanks, an air compressor, a moisture separator, an optional space heater, a 50-100 foot hose, t type air connection to the compressor, and a pretty metal rack with wheels. I already have 90% of this stuff here. The tanks for this kit that yield 1200 board feet of close celled foam are $750. This by far is the cheapest option for spray foam I am ever seen. I will probably be building one of these setups to at least finish the attic in my addition and the rest of my house. I can even get fancy and get a 100 foot pipe heater from Lowes to attach to the two hoses and wrap with insulation.

http://youtu.be/Cm6GI6zBiag

Update...

Used the 2 part foam kit on my crawl space and couldnt be more impressed. My crawl space originally had R19 fiberglass under the floors of the home. I recently placed R30 on the walls of the crawl in order to start encapsulating the thing. The plan was to pull the R19 out after I was done. In this case I pulled the R19 out over the last couple of weeks. I then pulled the R30 away from the walls and removed the plastic stapled to the rim joists and fastened them to the bottom of the crawlspace wall with a ramset type gun. I then sprayed the entire stone wall of the crawl with 1 inch of closed sell. This went all the way up to the subfloor on the exterior. I left the R30 off of the walls while it dried. The first day I did it I immediately noticed that the first floor was remaining the same temp as the second. Seems like we slowed the stack effect. The attic is still leaky so that will not change yet.

All in all I am impressed with the stuff. I will probably be contracting the addition to have one inch done prior to me placing cellulose on the walls.

So did you foam the under side of your sub flloor from the crawl space? I hope to do that and have heard it can make a big difference, although messy to do, since you are basically foaming it upside down and it can fall back down on you.

I foamed the outer walls of the crawl space. I left the underside of the subfloor open except for the 6inches or so overlap from the walls. My first floor heat pump is in the crawl space so it makes sense to not foam the subfloor and foam the walls. Also ground temps stay between 60-70 all year long. As for how messy it was, I wore an entire mil surplus chemical suit made for chemical warfare protection with CBRNE gas mask. I covered the mask with the exception of the hole in the filter with plastic. I washed the suit and would wear it again for something not requiring CBRNE protection.

Well I am officially sold on the sprayfoam. I went into the crawl tonight to inspect the foam and place the R30 fiberglass batts back up against the wall over the sprayfoam. I have to say that the crawlspace was HOT when I went under there. I have an airhandler down there and no matter what there will be a certain amount of duct leaks. So I put the R30 back onto the wall and the only gaps are on the rim joists that have only the sprayfoam. I would be happy to add another inch of sprayfoam there along with a layer of open cell on top.

My house has two heat pump units. I usually keep them at 67 to 68 in the winter. Today I have had them at 70 on the first floor and 69 on the second. I have to say that the heatpumps have come on maybe a total of 20 minutes in the last 4-5 hours. The second floor was actually at 69.5 deg when the stat was set at 69 and the heatpump had not run for the second floor. I can only imagine when I do the attic.

Spray foam is good stuff, but I'd venture a guess that the immediate benefits you're seeing are from sealing the air leakage. Much bigger factor than people realize.

I agree with the air sealing. There is no way I could have sealed the rim joists and all the little cracks without spray foam. The crawl space is actually uncomfortably warm now when the heat is on. Yes I put the R30 back up on the walls after the foam dried. That being said, the areas where the spray foam is exposed is warm to the touch instead of cool like the block use to be. I still have to bolt some rigid foam to the access door.

In the month of November I used 600kwh less than last November. True last year might not have been quite like this year but I doubt it had much different average. I can say for sure that the night time low was much lower this year in November. In addition we hosted Thanksgiving at our house this year for the family from New York state. This means more using the oven, microwave, 220v well pump kicking more, more using the electric dryer, more using he electric hot water, bumping the thermostats from 68 to 72deg F, the tv on the whole time, my bitcoin mining rig, and not to mention the uninsulated addition connecting to the house and existing attic (this sucked heat out of the house like a straw when it was being attached last feb.)

My spring project is definitely going to be the attic at this point!

A few more questions on your air sealing method:

1. Would you do this to a new home (if you were building a new home). I ask, because I am breaking ground on a 2 story home next spring (3500 sq' total- 1750 sq' each floor); 9' 1st floor ceiling; 10' 2nd floor ceiling height. I hope to air seal the interiors of all exterior walls before any rough in (plumbing, electrical, HVAC), after the house is "dried-in". I feel this is the proper time to do it before any electrical, plumbing, etc is in the way. But is your method realistic for this much surface area? I ultimately plan on netting and blowing cellulose in the exterior walls (2x6) after electrical/plumbing rough in is complete.

2. Do most agree that the proper time to do this on a new build, is before the electrical is installed (except for outside electrical outlets on the decks, etc...) and before any supply line plumbing ins installed? Or just air seal right before insulating?

3. I'd like to air seal under the sub floor of the first floor (crawl space), but I may opt to blow in expanding foam under the floor instead. Will that act as an effective air seal? Or should I air seal under the crawl space sub floor before expanding foam is installed? (My gut says yes)

1) What I did did not take long at all. I would have liked to have had a paint bottle but it still went quick.

2) If doing it again I would just use a 2 part rigid foam kit with about an inch applied. I still am thinking of doing this because I stopped working on that room to fix a few other things that needed fixing before proceeding.

3) One of the things I decided to fix was the crawl space. I sprayed 1-2 inches of rigid foam on the crawl walls. If you have your plumbing and ductwork in your crawl I would suggest just foaming the walls and leaving the floor bays open. I find it is pretty warm under there now and I wouldnt mind putting some radiant pex in under there with solar heated water pumped through in the winter.

"air seal under the sub floor of the first floor (crawl space)"
Air sealing with gaskets, caulk & good tape is relatively inexpensive and fast, so it makes no sense to ignore this step.

If you condition your crawl I wouldnt air seal the floor. Remember your building code for conditioned crawls most likely will require supply and return air. This makes air sealing the floor pointless and a waste of resources.

kogashuko,

Would your method be difficult to seal under the sub floor. My crawl space will NOT be conditioned, so I feel it is a good idea to air seal under the sub floor. Spraying upside down can be tough, no? I may just spray expanding foam under the sub floor, but I don't think that does as good a job of actually air sealing?

Either one will probably be messy. I found the expanding foam I used is a very good air barrier.

So I ordered two more foam kits and almost finished foaming my vented attic over my existing house during the heat wave this week. One end of the attic is still open to the addition which is only partially insulated. I also have to finish foaming part of the rear of the roof because I was beginning to get high on the nitrogen propellant used in the system since the CBRNE mask doesnt do anything for lack of oxygen.

I have to say with only an inch under the roof deck and 2-4 inches at the point where the roof ends at the eves there is a huge difference. The temp has dropped back down to low 40s high 30s outside and this room I am sitting in using my computer is unbearably hot. Also, the heat hasnt been on since last Tuesday when the outdoor temp got to 70 for a few days. I know I will probably need at least another inch on the whole roof before summer but the properties of a sealed attic is insane. I could even leave it at 1-2 inches and add R19 Batts under the foam.

I dont know if anyone else has noticed such a change when installing such a small amount of the stuff?

I dont know if anyone else has noticed such a change when installing such a small amount of the stuff?

Is it the insulating properties or the effects of the air sealing that you are noticing?

Ii's probably the air sealing that he is seeing. It makes a huge difference when you keep the heat inside the house.

I am going to reread this entire thread soon. I'm presently trying to put together the budget to do my entire house next fall. The house should be dried in and ready for interior work by late fall. Air sealing the interior of the outer walls is one of the first things I hope to accomplish.

1. Would you mind posting or PM'ing me a list of the equipment (tanks, hoses, guns, etc...) that I would need to procure to do this myself? I know it's a lot of work, so if that's too large a request, I would understand.

2. Re posting the name of the roof mastic you settled on (I think you settled on a product you picked up from Lowes?). It was a roof mastic that you ended up blowing through the gun to air seal, right?

3. Did you say you felt that spraying closed cell foam on the inside of the exterior walls also acts as an air seal? That is contrary to what I've read elsewhere (that it can't be relied on to be a complete air seal solution but a great insulator). Anyone else care to opine on that point? i.e. if you spray closed cell foam and fill up the exterior walls, you don't need to air seal?

Yeh the closed cell foam should be an airseal in the bays but not between the floor and the walls, you will still need to calk.

With the spray foam option you just need to grab a DIY kit and it contains everything you need except the mask and old cloths. Go by what type of mask the particular manufacturer says. You also need some sort of venting if you are going to be in a tight space. This is because the DIY kits use nitrogen as a propellant and no mask other than scba will force oxygen into the space. If you are in a large room it should not be a problem but when I was wedged between the roof deck and the ceiling of my second floor getting the eves I started to notice my vision getting smaller, begining to get confused, and overall drunk feeling. I got out of there quick and the feeling went a way in a few minutes. FYI, not enough oxygen can kill you so use common sense. A fan blowing air in might be all you need.

With my method I grabbed a $10 bed liner spray gun and selected the white roof mastic at lowes. I dont remember the name of the stuff but I can find the receipt. The air compressor I already had.


Here is some raw video of the spray foam application in the crawl.

http://youtu.be/iPCc9mqglCM