Deep Energy Retrofits , Energy Efficient Stuff , Indoor Air Quality
Risks Associated with Poor Spray-Foam Installations
‘Leathery’ spray foam has lost it’s air pockets and is no longer effective. Is it inert in this condition?
A few months ago, I posed a question about spray foam installations and wet wood to some of the forums I belong to.
I got an astounding response — some of it snarky, most of it super helpful. I’m still editing a longer piece that will cover the responses, but in the meantime I ran into this:
Squishy, deflated, leathery 2lb foam. This was installed on the leaky concrete wall of a basement stairwell with a partial foundation, with a connection to an unflashed framed wall above. The house was built in 1836, while the stairwell was obviously a much later addition. The foundation is very wet, the tidelines on the mechanical equipment hitting the 8″ mark, and obvious water markings on the exposed part of the original rubble foundation. After reading all the comments from my original question about spray foam installations and the considered responses, I have to ask myself what spray foam contractor worth their salt would install in such conditions?
The water damage is easily seen throughout the rubble basement walls. The insulation was sprayed onto the top 24 to 36″ of the rubble wall, but has lots of voids and cracks. There is also a wide range of spray consistencies visible — some of the foam looks positively cumulous, while other parts look like smooth lava. Rookie installer? D-I-Y install from a kit system? Who knows — the homeowners purchased this spring and have no records.
From a cursory walk around the perimeter of the house, I knew there would be one fixable source of water leakage into the foundation: over the 175 years, the grade had settled (dramatically in some places), and snow melt and rain water were caught and funneled down into the rubble wall. Straightforward solution to that cause: regrade. Other problems with the foundation, not so straightforward, but we’ll see.
Water is getting through the spray foam…that’s a crappy installation with all those of voids.
The state of this spray foam made me wonder about health issues, because it had so obviously perished and was dripping this ghastly caramel coloured ooze. There is some field research being done to look at the risks associated with installing spray foam (Field Research to Provide Deeper Look at Spray-Foam Risks – BuildingGreen), but I am not familiar with any studies published on long-term health risks to occupants as a result of crap installations like this one. There are substantiated issues with offgassing immediately after installation, yes, but let’s assume that the product performs as its data sheet indicates, and 24 hours sees most of the offgassing dissipate in a properly done installation.
Water penetration in walls is a problem, period, regardless of the type of insulation that is used, so I’m not freaking out on one type of insulation. From many, many problematic basements, we know what is likely to happen in below-grade frame wall cavities filled with fiberglass batt insulation. When the fiberglass gets wet, it doesn’t drain well or dry out and so causes mold growth given enough warmth. That causes health problems. Cellulose is a total no-go below grade for the same reason. As far as I’m concerned, rockwool is the best option for fibrous insulation below grade. Or spray foam. But only once the foundation is dry. There are so many indoor air quality and eventual structural problems that can be minimized or eliminated by eliminating water leakage into the foundation, and so many that can become exponentially worse by NOT eliminating water leakage into the foundation.
Deep Energy Retrofits , Energy Efficient Stuff , Indoor Air Quality , Stuff that makes me crazy
Damp basement season. It’s coming
What are you going to do about it? Hopefully not install an exhaust only system to pull more humid air into your humid basement.
Don’t. Do. It.
I’ve been discouraging these systems forever, here in Nova Scotia. They don’t reduce humidity levels in basements, but that’s what the marketing infers. What they do is exhaust the humid air from the basement while bringing in humid air from the outside. There is no way to reduce relative humidity levels and stop condensation without a) increasing the ambient air temperature so that it can carry more moisture while at the same time increasing the temperature of all exposed (or first condensing) surfaces or b) stripping moisture out of the ambient air (that’s what a dehumidifier does — oh, wait, that’s the market these exhaust only systems are muscling in on). In reality, the best way to deal with humid basements is to #1 Find the moisture source(s), and #2 Eliminate them. That’s the straight up, bottom line, end of story.
Moisture sources like open sumps are the problem — sealing this off before doing anything else will go a long way to reducing the moisture level in your basement or crawlspace. Note the white efflorescence on the wall — that’s salt crystals left behind from moisture migrating through the wall.
Open sumps, cracks in concrete that allow bulk water into the basement, these are pretty obvious sources. Less obvious sources include crappy drainage at the foundation, damaged or non-existent drainpipe leaders, high water tables.
Then there’s the fact that cooler surfaces cause moisture to condense out of warm, humid air. Concrete or masonry, present in most basements, are terrific first condensing surfaces. Insulating concrete and masonry can help to reduce the extent of condensation. But only if all moisture sources are dealt with so there’s trapping of more moisture in the basement…so back to #1 above.
Read this blog post by Allison Bailes at Energy Vanguard if you want more details about the pitfalls of exhaust-only systems and a fantastic in-depth explanation of why they won’t, don’t, can’t work in basements. Although he references New Orleans specifically, the physics that lead to problems with humid air and cold surfaces, along with the need to eliminate moisture sources in basements and crawlspaces are the same everywhere. The severity of the problem is related to the climate zone and the condition of the basement.
According to a recent article, spring, when it finally crawls its way up the continent, will bring with it a rotten allergy season. On top of the usual pollen and mold growth, allergy sufferers will be combatting the effects of rapid changes in temperature and moisture in the air. People who have asthma will be feeling the strain now — more so as the temperatures start to ping-pong. Good news is such a cold winter likely killed off more pathogens than the last few winters. Bad news is a wet warm spring could bring higher mold spore counts. Ugh. As a person who deals with both asthma and allergies, I’m already feeling the drag on my energy and there’s a brand new 3 inch layer of snow in my neck of the woods.
Prepare for it, prepare your clients for it:
- Clean and replace all filters – furnace, HRV, A/C
- Keep mold at bay by keeping humidity levels down in the house – run the bathroom fan religiously, use a dehumidifier in damp basement areas
- Keep windows closed early in the morning – tree pollen counts are highest then
- Take your shoes off at the door to stop tracking pollen all over the house
- Pets can bring pollen into the house too – keep them off upholstered furniture and carpets/rugs, or vacuum frequently, even daily (ya, right, that’ll happen at my house…)
- An air purifier with a HEPA filter can help reduce pollen counts, these can be add-ons to ventilation systems or stand alone plug-in units for individual rooms
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