The thread where everyone teaches me about spray foaming...

Backstory-  We got really lucky during Covid and bought a $ house, but on a $$$$$$$$$$$$ property.  We should have just knocked the house down and lived in the big garage, but I digress.  

So this house is in close proximity to a lake, and one of the single biggest issues has always been moisture/drainage/runoff control.  The house started as a camp with 1 or 2 additions, and is built on pilings.  Because neither my wife or I know how to successfully print money, putting in a concrete basement in is not feasible-  We are so low on the water table that even that would pose it's own issues.  Over the past 5 years, I've been picking away at one moderate sized improvement project to help with moisture mitigation in the crawlspace and home.  In sequence, we have done-

- Professional mold abatement and treatment

- Full perimeter french and trench drains on the exterior, run to a drywell downstream of the house (helped with rain runoff)

- regrading of the driveway and upper areas of the property 

- Gutters and downspouts

- Massive sump pit with interior drains, pumped out to said drywell

- 10mil vapor barrier, fully taped and seamed, along with a dehumidifier on a humidistat.  

Since then, our crawlspace has gone from a wet, disgusting dirty, muddy mold  haven to a 60% humidity, clean and bright space that is honestly somewhat enjoyable to work in...  But the years of wetness and moisture has rendered the old paper backed pink floor joist insulation basically useless.  We've always had trouble heating the house in the winter, and this is 100% the reason why.  Some joist bays don't even have insulation anymore, and because it was a camp, some of the construction techniques are, um, sub-par to say it nicely.  Here's where I'm asking the question-  Is it worth it financially and DIY'ably to spray foam in myself, or is this a job best left to the pros?  I know I want closed cell, and 3" approximately for an R21 equivalent, and with the knee walls and joists I'm looking at about 1800sf of coverage.  That puts me at about 5-7 'DIY kits', depending on which calculator you use, which at todays rates is about $5000.  I've gotten 2 quotes to do the job, both in the same $9-10k ballpark.  Part of me feels like this might be one to leave to the pro's, but it's also $5000 in savings if I just suck it up and do it myself.  so I'm asking the hive, does anyone have any direct experience with spray foaming, and especially spray foaming overhead, with the DIY tank kits, and if so, how bad was it? 

Thanks in advance! 

Lately I've been reading stories from the UK about spray foam.

Lots of people got talked into spray foaming their attic spaces about 15-20 years ago when Mike Holmes and everyone else started having a serious hard-on for the stuff.

Fast forward to today, foam holds moisture and causes the roof structure to rot from the inside out.

Lots of people can't get mortgages on these places after all the experts told everyone what a great idea it was.

I was skeptical then. Now, I won't put that stuff in my house.

If it were me, I'd put in Roxul insulation. It's been around at least 40 years and won't burn. I remember my father selling the stuff to folks by putting a wad of it in his hand, putting a penny on the wad of insulation and heating it red hot with a blowtorch.

In reply to ShawnG :

The problem with running a conventional-type insulation is that I'm also looking for draft stoppage.  It's an old converted camp, and nowhere anything near airtight.  I've discussed the internal rot issues, and that only seems to happen with zero access to airflow, which in this use case, is not relevant.  It'll stilll see plenty of ventilation through the knee-wall vents in the crawlspace, and in the living area above it. 

Can you even get your hands on the equipment and materials?

NOHOME said:

Can you even get your hands on the equipment and materials?

 

There are a number of readily available, pre-pressurized 'propane tank' style kits that one can buy.  They supposedly cover 600 board feet at 1-2" of thickness.  

foamitgreen.com, is one of the companies I've been researching, fwiw. 

Went thru a problem with moisture in the house, nowhere near yours but I still learned alot.  You need an extensive education on options and pros/cons of each.  The moisture has to get somewhere, in my case when it is contained to a space it rots anything it can rot.  Look at options and maybe grading the lot to put the whole house above the water table.

golfduke said:

In reply to ShawnG :

The problem with running a conventional-type insulation is that I'm also looking for draft stoppage.  It's an old converted camp, and nowhere anything near airtight.  I've discussed the internal rot issues, and that only seems to happen with zero access to airflow, which in this use case, is not relevant.  It'll stilll see plenty of ventilation through the knee-wall vents in the crawlspace, and in the living area above it. 

 

Where are the drafts coming from?  Will the spray foam fix that?  Might a different solution also fix that- like an exterior wrap that is now commonly used?  That way the moisture barrier is outside of the wood, which is also a draft barrier.  Then any insulation will work.

Of course, that means the building is resided....

If it's windows, then spray foam isn't going to help.  

It also could be the foundation/house interface- I recently did a lot of work sealing that up with rodent foam, as my home had a ton of gaps easily big enough for a mouse to get through, let alone wind.

I'm not clear, are you planning on spray foaming the underside of the floor? It's more common in my area to just insulate the rim joist/sill plate. That keeps all of the outside air out from under your house, and you typically need less material too. Spray foam is a popular option, but you can achieve much the same thing with rigid foam panels and cans of spray foam for a more DIY friendly approach:

I used to love the idea of spray foam. And then I bought a house with water damage. The rim joist and crawlspace walls had been foamed at one point, but there was a plumbing leak above the foam. I'm not sure if the spray foam was open cell or closed cell, and that could make a difference, but it soaked up the water and held it on the framing for the entire wall for years. A single leak in the center of the wall ended up ruining about 40ft of rim joist and sill plate as well as the floor joists that ran along that wall. I still see the appeal of closed cell in many applications, but I'm definitely more hesitant to have it anywhere near plumbing now.

alfadriver said:

golfduke said:

In reply to ShawnG :

The problem with running a conventional-type insulation is that I'm also looking for draft stoppage.  It's an old converted camp, and nowhere anything near airtight.  I've discussed the internal rot issues, and that only seems to happen with zero access to airflow, which in this use case, is not relevant.  It'll stilll see plenty of ventilation through the knee-wall vents in the crawlspace, and in the living area above it. 

 

Where are the drafts coming from?  Will the spray foam fix that?  Might a different solution also fix that- like an exterior wrap that is now commonly used?  That way the moisture barrier is outside of the wood, which is also a draft barrier.  Then any insulation will work.

Of course, that means the building is resided....

If it's windows, then spray foam isn't going to help.  

It also could be the foundation/house interface- I recently did a lot of work sealing that up with rodent foam, as my home had a ton of gaps easily big enough for a mouse to get through, let alone wind.

So the house is a very unique setup.  It's on a lake, and as such, there really isn't any way to get the house above grade, save for demolishing it and starting over again.  The air gaps are coming in through the actual floor, where there is 3/4 plywood and tongue and groove hardwood above that, but no actual vapor barrier in between.  I've replaced all windows and doors in the living area already, and they're pretty airtight (They very much were not before).  In a typical winter, where the house is at 65 degrees, a heat gun tells my that my floors average 40-50.

Think of my crawlspace as essentially open to the environment-  There are concrete pilings every 12' on the home perimeter, with wooden/sided knee walls filling the void.  the plastic vapor barrier runs from the bottoms of the knee walls and covers the dirt crawlspace floor.  There is a massive dehumidifier in the actual crawlspace above the vapor barrier for moisture control.   Between those gaps and the concrete pilings, and the gap between the knee walls and rim joists in some spots, and the holes in the floor for various electrical/hvac/plumbing stops, the areas of access are plentiful and sizeable.  that's why closed cell is so appealing to me-  There's simply so many that to properly seal and encapsulate the walls of the crawlspace... well I might as well just start from scratch again.  

I know I sound like a stubborn curmudgeon, I swear I'm not.  I'm listening, and open to any and all ideas.  Just the idea of rolling in a bunch of backed fiberglass after I'm literally removing hundreds of feet of the same, just wet, degraded garbage, seems counter-intuitive to me is all. 

The Dow Froth-Packs are very DIY friendly,  I sprayed out 1200 board-feet in my basement with no issues.  I had a Tyvek suit and forced air P100 respirator.  Easy enough.  

If thats the route you decide I have more tips n tricks available.

IIRC, Mike Homes et al used a lot of open cell foam and filled wall cavities.  No wonder these cause problems since its just a sponge.  Closed cell foam will not absorb moisture.  

93gsxturbo said:

The Dow Froth-Packs are very DIY friendly,  I sprayed out 1200 board-feet in my basement with no issues.  I had a Tyvek suit and forced air P100 respirator.  Easy enough.  

If thats the route you decide I have more tips n tricks available.

IIRC, Mike Homes et al used a lot of open cell foam and filled wall cavities.  No wonder these cause problems since its just a sponge.  Closed cell foam will not absorb moisture.  

Thank you!  This is similar to my use case, so I'll take any more tips and tricks as you have.  You can email me at golfduke 9883 at the google mail, or feel free to just post them here. Mostly I'm curious as to your experience spraying overhead, whether the board feet was relatively accurate in terms of real world coverage, and how long it took you to spray out 1200bf... and how many nozzles you went through. 

Did you notice an improvement in insulation/drafts?  

Okeydoke.

• I did half my basement (walls included) and all my sills with 1200 bdft in a 1000 sqft house. 
• I had new framed walls inside my basement, I framed them with 2x4s spaced approx 1/2 to 3/4" off the original block basement,  That gave me enough room to spray between the studs and the wall.  I made my walls square, my foundation wasnt square.
• Spraying overhead was no issue, the stuff is real sticky,.
• I went through 5 or 6 of a 10 pack of nozzles, but I did it all in one run.  You only need to change nozzles if you stop for a few minutes.  If you plan your spray, you could do it all on one nozzle.
• It took me about 3 hours to spray out 1200 bdft, but that was doing some running around in the basement too.  It sprays out fast.  As fast as you can pull the trigger.
• I didnt clean anytihing, just dumpstered it all when I was done.  I wasnt going to do more.  
• When you crack the froth packs open, leave them in the cardboard boxes.  Then spray your foam in the cardboard halfway up.  The heat from the reaction will raise the bottle pressure and make it spray out real nice.
• When the spray gets sluggish, fill the rest of the boxes with spray foam.  This will kick the temp higher on the tanks again and let you empty them fully.
• My math said I needed 1000ish board feet to get the coverage I was desiring, and I did.  I went a little light in the sill cavities in some places then came back and ran a few more inches in them on the north and west sides of the house as thats where we see the most cold and wind.
• I am sure it made a difference, just tough to quantify.  I can tell you that in my 1000 sqft house with good windows and doors and decent insulation in the walls and ceilings we use $600 a year in fuel oil to heat it comfortably,  Its a tight, cheap little house  My floors feel warm.
• I paid about $1/bdft from Menards and would do it again.  

Awesome, thanks again!!! That's all super useful info, and I appreciate it very much!