Our original plan for sealing the gap between the slab and the wall was to apply spray foam to the bottom 2 feet of the walls - only where there wasn't any existing fibreglass batt insulation, in the finished part of the basement, and the complete walls in the utility room. Based on the perimeter of the basement, and the yield of the Touch-N-Foam System 600 kit - up to 600 board feet (600 feet long, one foot wide, one inch thick) I figured with two the of the System 600 kits I would be able to get a 2 inch thick minimum coverage.
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| One inch thick application of Touch-N-Foam System 600 |
The instructions for the kit, the videos that demonstrate the kit, and the packaging all reinforce the importance of three temperatures for optimum yield - the temperature of the cylinders (minimum 21C, 70F), the temperature of the air (minimum 16C, 60F), and the temperature of the suface the foam is to be applied on (minimum 16C, 60F). When spraying basement concrete walls in late winter - achieving the minimum temperature of the concrete was a challenge. I installed a 2000W convectair in the utility room to supplement the central forced air furnace. My furnace has a zoning system, so I closed the zones for the main floor and upper floor of the house, and forced recirculation only in the basement. I disabled the heat pump to force the electric backup heat in the furnace to run, and I had this run for 2 days straight to try to heat up the concrete walls. I just managed to get the concrete to 16C in most places, some places a bit higher, some places a bit lower.
A note of caution before getting into the details - these kits are recommended for professionals - and improperly mixed or applied foam can cause poor results - in the worst case - you may be removing and cleaning up improperly applied foam. I'm not recommending that you follow this example - I'm just trying to demonstrate my experience. Unless your completely confident in your abilities - take a second thought and strongly consider hiring a professional, licensed contractor.
I made sure to take care of all the preliminary preparations ahead of the day that I was going to apply the foam. All the void spaces were vacuumed out with a shop vac - removing all the cobwebs and loose construction debris to optimize the bonding of the foam to the concrete. Electrical cables that were unsupported in the void behind the stud wall were fixed to the studs so they would not fall into the gap at the bottom of the wall between the slab. I also bundled the wires as much as possible, to have fewer interferences to deal with when spraying foam. All the electrical outlets were protected with plastic bags and tape.
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| Protect your outlets. |
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| Protect anything in front of your walls - these are electrical cables and irrigation lines that run into the back yard |
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| Buy a couple of rolls of painters plastic - it will come in very handy to protect from overspray |
The foam is shipped in two cylinders, a part A and part B, and the chemicals mix in the replaceable nozzle of the gun. If you pause for more than 30 seconds, the chemicals start to set in the nozzle, and you have to replace the nozzle. Since I had to work around the perimeter of my basement, I decided to make a simple dolly on four casters to support the cylinders, so I could move the cylinders quickly and easily.
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| Four Casters Installed on top of an Ikea Ivar Shelf Make an ideal foam kit dolly |
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| These castors are inexpensive, can be picked up at any home improvement store |
Once the drywall was off all the walls in the utility room, I got an early start on a weekday once everyone was out of the house. The application guide recommends adequate ventilation, so I opened a door passage to the garage, and opened the garage door to allow some air circulation when spraying.
I went with the recommended personal protective equipment (PPE) - a painters tyvek suit, the safety glasses supplied in the kit, and a half mask organic cartridge painting respirator by 3M.
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| 3M Half Mask Organic Cartridge Respirator |
I watched the instruction videos a few times to familiarize myself with the operation of the kits and the application of the foam, and followed the instructions carefully. I won't repeat the instructions here - the videos are excellent and easy to follow.
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| Everything laid out and ready to start - Foam Kit with hoses and gun attached, scrap cardboard for testing, garbage can with bag for priming gun and testing foam. |
Everything went pretty well as shown in the video - once the gun was primed and shooting well mixed foam - I started by foaming the gap in the slab, and the contours of the wall openings. I was careful to apply the foam no thicker than recommended - 1" at a pass - to try to optimize the yield of the foam. This meant that I would have to go back and do a second pass.
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| Foam Application - Perimeter Pass |
The kit did not come with any fan nozzles, only the spot nozzles which spray about a 4" wide bead of foam. It took me about an hour and 30 minutes to completely empty a kit - it takes a fair bit of time to do wall coverage with only a 4" wide pass in thin layers.
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| Completed wall after the second pass. |
When the first kit was running low on foam - I noticed air bubbles coming up the line a bit more frequently, and the pressure dropped in the spray. I didn't notice right away that I had completely exhausted the A cylinder. I ended up with about 6 square feed of foam that hadn't mixed properly and wasn't setting, so I had to scrape it out with a paint scraper and then start the second kit to re-apply fresh foam.
Once all was completed, and had cured for a day - I went back and measured my application. I had averaged about 3/4" thick application over about 600 square feet of wall surface, plus about 75 feet long of sealing the gap between the slab and the wall. I figure I got fairly close to the advertised yield of the kit - but in order to achieve 3 inches of cured foam in order for the foam to act as a vapour barrier - I figured I was going to have to purchase another 4 or 5 kits. I was now in the cost territory of having a foam contractor come in, and, I had spend a total of about 6 hours in preparation, application and cleanup in order to do about half of my surface area to about 1/3 the required foam thickness. So - the decision was easy - I was going to get a contractor in to complete the job. I had already hired an insulation contractor during the original renovation to apply spray foam to a window well in my attic, and to blow cellulose into my attic. I called him and set up an appointment for the end of the following week.
Another issue was that at the end of applying one and a half kits - my eyes were getting irritated. I was limited with how much ventilation I could allow without dropping the air temperature due to the cold weather. I ended up purchasing a full face organic cartridge respirator in order to finish off the second half kit remaining - just to avoid further eye irritation. If you're going to apply one of these large kits indoors - I would highly recommend the full face respirator.
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| 3M Full Face Organic Vapour Respirator |
In the end - I got a good quality foam that adhered well to the concrete - but I underestimated how labour intensive it was going to be for a large job. I think these kits are ideally suited for smaller jobs - where you need to apply a single kit - such as doing all your rim joists in your basement, for example. Larger jobs - where you're applying to entire wall surfaces - you're probably better off with hiring a professional contractor.
If you are going to apply one of these kits yourself, my biggest recommendation would be to follow the manufacturers application instructions to the letter - application temperatures, work procedures, and so on - to maximize the chance you get a quality result.
And - don't try to get every last bit of chemical out of the tanks - as soon as you notice a change in the foam output quality - stop, change the foam nozzle so you have a clean applicator, and check the foam by doing another test on scrap material. Any foam that isn't properly mixed will not cure and you'll be scraping it out - not an easy job considering how viscous and sticky the product is.
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| An example of improperly mixed foam - the A cylinder had run out, and I had continued applying foam. This foam didn't expand and cure, and stayed wet and sticky, and had to be scraped out, cleaned, and foam reapplied overtop. |
In my next post, I discuss completing the basement job with a contractor, and what we found behind some of the finished basement walls that caused some difficulty - some vertical foundation wall cracks.
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