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Great thread. One more I use: the icepick test. Spray a golf-ball size bead and wait exactly 30 seconds. Poke it with an icepick or thin screwdriver. If it goes in smooth and the foam springs back = good ratio. If it tears instead of compresses = resin rich. If it goes in like butter with no resistance = ISO issue or heat problem. Takes 2 minutes and tells you everything before you commit to a full pass. I do this at the start of every job and after any drum change.
Indiana CZ5 contractor here. Yes, 2 inch closed cell on rim joists is a Class II vapor retarder – you do not need poly there. My process: spray the sill plate and 6 inches of foundation wall first, then move up to the full rim joist. This creates a continuous air seal. Then lap the ground poly barrier up the foundation wall 6-8 inches and tape it. Perfect thermal and vapor bridge with no gaps. I have done it this way for 5 years with zero issues.
We switched to HFO (Lapolla 4G) about 8 months ago. Honest review: yield is about 5-8 percent lower per set, handles slightly differently in cold, but cell structure is actually better – finer and more uniform. On the business side we have gotten 3 commercial jobs specifically because we marketed it as low-GWP foam. ESG-focused clients pay the premium. It is not a massive game changer but it is a real differentiator in the right markets.
This is excellent advice especially on pricing. I wasted 2 years undercutting everyone and wondering why I was always broke. My accountant finally showed me I was making about $8 per hour after expenses. Now I target $85-95 per board foot installed for closed cell residential and I book 6-8 weeks out. The customers who push back hardest on price are usually the ones who will also push back on every other thing. Let them go to the cheap guy.
Treated lumber and OSB is a known adhesion issue with closed cell. ACQ and CA copper-based treatments can inhibit adhesion significantly. Lapolla tech bulletin actually warns about this. Your fix: prime with a water-based primer before foam application on any treated material. For OSB specifically, I now always ask the GC if it is treated before quoting. If it is, I add 15 percent for primer cost and time.
Minnesota contractor here – cold starts are everything in our market. The H-40 has a larger heat exchanger which warms up faster AND holds temp better in sub-zero conditions. I lost a $15k job last January because my old H-25 could not maintain temp at -15F. If you are doing MN winters seriously, the extra $8k is absolutely worth it just for cold weather performance alone. The added output is a bonus.
Upgraded from H-25 to H-40 last year. For residential it was honestly overkill. Where the H-40 shines is large metal buildings where you need sustained output for 6-8 hours straight. If your commercial is mostly small buildouts, save the $8k and put it into better drum heaters. The H-25 will handle 95% of what most guys do.
This is more common than people talk about. I had a case go to small claims court – customer won $2,400 for remediation costs. The judge sided with them even though our application was within spec. My lawyer told me to ALWAYS include a contract clause about temporary off-gassing. I now use an odor disclosure form that has protected me twice since then. Happy to share the template if anyone wants it – just reply here.
Had an almost identical situation 2 years ago. Icynene Classic, same temps. Turned out to be a ventilation issue – the attic was too tight after sealing and the amine off-gassing had nowhere to go. We cut in two 4-inch passive vents and the smell was gone in 2 weeks. Check if the attic has proper air exchange after the spray. Open cell in a tight attic without mechanical ventilation can accumulate VOCs longer than expected.
Great thread. One thing I will add about the solo CDL question – even under 26k you still need a DOT number if you cross state lines for work. Check your state regulations. Also worth mentioning: solo operators should budget for a helper on large jobs. I do 90% solo but I keep a reliable part-time guy on call for any job over 3000 sq ft. The efficiency gain on large jobs more than pays for his time.
Solo operator here in Georgia for 4 years. I went the enclosed 16-ft trailer route and never looked back. The van setups are cleaner but you lose drum storage and the ability to work in the elements. In the South we get afternoon thunderstorms constantly – having a full enclosed trailer means I never have to stop a job for weather. For generator sizing: a Kubota diesel 12kW handles the E-30i fine.
Solo operator here in Georgia for 4 years. I went the enclosed 16-ft trailer route and never looked back. The van setups are cleaner but you lose drum storage and the ability to work in the elements. In the South we get afternoon thunderstorms constantly – having a full enclosed trailer means I never have to stop a job for weather. Generator-wise, I went with a Kubota diesel 12kW and it handles the E-30i fine.
I ran solo for 6 years with a truck bed skid unit (Gusmer GH-2) and a 7500W generator. The CDL thing is real – stay under 26k GVWR. My Ford F-350 dually with an 8-ft flatbed skid setup stays just under that limit. Main challenge working solo is hose management – I built a wall-mounted retractable reel system in the bed that made a huge difference. DM me if you want photos of the setup. Also for generator sizing: the E-30i draws about 8-9kW at full load, so your 15kW should be fine.
Working on a 40×80 metal building project in Tennessee (CZ 4A – mixed humid). Owner wants to convert it from agricultural to a climate-controlled shop/garage.
Plan is to spray closed cell foam directly on the metal roof deck and walls. I am concerned about the condensation plane.
With a metal roof, the roof deck gets extremely cold in winter. If I spray 2 inch of closed cell on the interior, is the dew point going to end up within the foam layer, or is 2 inch sufficient to keep the dew point inside the building?
Running the numbers with an online dew point calculator suggests I might need 3-4 inch on the roof to fully control condensation in CZ 4A. Can anyone confirm this from field experience?
Also: what is the typical adhesion like on painted or galvanized metal? Do you prime first?
CZ4A metal roofs – I use a rule of thumb of R-15 minimum (about 2.5 inch closed cell) for walls and R-25 (about 4 inch) for the roof deck. At 4 inch closed cell, the dew point stays outside the foam layer in CZ4A even on worst-case winter nights. For adhesion on galvanized metal: no primer needed if the metal is clean and dry. On painted metal it depends – fresh acrylic paint is usually fine. Old chalky paint needs light sanding first. Always do a pull test before committing to the full roof.