If the foam does take on water it is an easy fix. The heat recovery unit heats the incoming air with the outgoing air in the winter without mixing the two so the building get fresh dry air with minimal energy loss. We recommended a humidity level range of 35% to 45%. How they work is they remove the stale humid air from inside a building replacing it with fresh drier air from the outside. In cases where high humidity is an issue we recommend an HRV or heat recover ventilator commonly know as an air to air exchanger. It is possible for closed cell spray foam to take water on in the case of abnormal high humidity for extended periods of time, like months. The home owner cleaned out the house and we sprayed the remaining portions of the basement. The foam was still dry and when we dug through it to the concrete substrate it was still fully adhered.
When the water receded we did a absorption test and adhesion test. We have actually had a basement that we spray foamed with 3″ of closed cell foam get completely flooded for over 3 weeks. Unfortunately, some open cell insulators will skip this step and downplay the importance of a vapor barrier – not recommended! All other benefits aside, it is because of this importance of controlling moisture (vapor) that we will always strongly recommend spraying closed cell over open cell in just about every insulation project we tackle.Closed cell spray can take water for quite some time and not be adversely affected. This is still an imperfect solution, however, as every staple, drywall screw and electrical box will create a penetration through the plastic and soon your vapor barrier won’t be much of a barrier anymore (but is still much preferred over not installing one at all). This problem can be mitigated somewhat by installing a plastic vapor barrier (visqueen) over the insulation before hanging the drywall. Voila! Wet walls, with rot and mold soon to follow. Fiberglass and open cell foam, on the other hand, will let that vapor pass right through and condense on the cold surface behind the insulation. Closed cell foam does not absorb moisture, it will act as its own vapor barrier. There’s always some amount of invisible moisture, or “vapor” in the air (think “bathroom after hot shower” for a visible example). It is not just air that one needs to count, because even cold air and moisture can gain success if the holes and cracks are not sealed properly. If you’ve ever removed an old fiberglass batt only to find a wet, moldy surface behind (as often as we have), you’ll understand the importance of a vapor barrier. In the building trades there’s an old, simple saying: “water wins!” And this is absolutely true - from roofs to foundation walls, to insulation. However, moisture control is the most critical aspect of any building project. We understand - many topics bore us too (but not this one). Can you just give me the quick and dirty? If it didn’t bore me to death I bet I could spend all day reading about the subject.
In basements and crawlspaces it can seal out the ground moisture and prevent that damp feeling and smell. It doesnt absorb water and in case of flooding, wont retain moisture and remains effective after the building is dried out. What about vapor barriers? Doing a Google search on “vapor barriers” brings up a ton of results. Does spray foam insulation absorb water Unlike other materials used for insulation, spray foam is a moisture barrier.
Since current energy code mandates an R-21 minimum in wall cavities, open cell can only be used in 2圆 or deeper walls by comparison closed cell can be sprayed in a 2x4 wall cavity and still satisfy the energy code. In order to get the same insulating value, open cell must be sprayed twice as thick as closed cell. However, open cell has half the R-value per inch as compared to closed cell – roughly R-3.5/in to closed cell’s R-7/in. Does one insulate better than the other?īoth open and closed cell foam will form an air-tight seal. Open cell is very soft and “spongy” and can be ripped out by hand closed cell is very hard and must be cut with a knife to remove. Closed cell can be sprayed with a much smoother finish (but will still have an “orange peel” texture). As it’s sprayed, open cell expands much more than closed cell does, which gives it a much “bumpier” look. So why would anyone choose open cell, you ask? Mainly for cutting costs. In a nutshell: unless you’re insulating for sound, closed cell is the better product: it doesn’t absorb water (so no vapor barrier is needed), it adds strength and rigidity to the structure and it has a greater R-value per inch (which comes into play when the insulation cavity is shallow, i.e. What are the differences between open and closed cell foam?