3 ms·

Interesting, why isn't the moisture on walls behind insulation ever an issue on new construction?

by badpun 4y ago

brtkdotse 4y ago
Old constructions are diffusion open, meaning moisture can move freely in and out of it. New constructions are diffusion closed, meaning you have a steam barrier on the inside which blocks the moist indoors air from traveling into the walls. This however requires an airtight house and mechanical ventilation.
__alexs 4y ago
Because they use a dual layer construction with an air gap between the inner an outer walls. This gives space for condensation to occur and evaporate again without effecting the living space. In old buildings with solid walls you can get condensation on the walls that will evaporate because the living space is heated and we'll ventilated. If you clad that wall in insulation you can prevent the evaporation which leads to damp problems.
sgerenser 4y ago
In addition to what was already said, there definitely is and has been many moisture issues on walls and exteriors in new construction. A condo building near me had to have its exterior completely torn off, and lots of sheathing, insulation, cladding, etc replaced due to a botched install of EIFS. Google for “EIFS failures.” This was a big problem in the 80s/90s or so but apparently it’s still happening, at least with subpar builders.
throw0101a 4y ago
> Interesting, why isn't the moisture on walls behind insulation ever an issue on new construction? Newer building codes have started to mandate more external insulation: * https://www.buildingscience.com/documents/insights/bsi-001-the-perfect-wall https://www.buildingscience.com/documents/insights/bsi-001-t... Depending on the climate zone, up to half the insulation may be mandated to be on the outside (behind some kind of cladding (brick, stucco, siding) to protect it from UV and bulk water). Per the above article, by having the outside be insulation, your interior structure is kept warmer, and so condensation is less likely to occur. Do a search for "Joseph Lstiburek" and "Matt Risinger", who have lots of articles and videos on building science. * https://en.wikipedia.org/wiki/Building_science https://en.wikipedia.org/wiki/Building_science

Interesting, why isn't the moisture on walls behind insulation ever an issue on new construction?

by badpun 4y ago

Interesting, why isn't the moisture on walls behind insulation ever an issue on new construction?

Old constructions are diffusion open, meaning moisture can move freely in and out of it. New constructions are diffusion closed, meaning you have a steam barrier on the inside which blocks the moist indoors air from traveling into the walls. This however requires an airtight house and mechanical ventilation.

__alexs 4y ago

Because they use a dual layer construction with an air gap between the inner an outer walls. This gives space for condensation to occur and evaporate again without effecting the living space. In old buildings with solid walls you can get condensation on the walls that will evaporate because the living space is heated and we'll ventilated. If you clad that wall in insulation you can prevent the evaporation which leads to damp problems.

sgerenser 4y ago

In addition to what was already said, there definitely is and has been many moisture issues on walls and exteriors in new construction. A condo building near me had to have its exterior completely torn off, and lots of sheathing, insulation, cladding, etc replaced due to a botched install of EIFS. Google for “EIFS failures.” This was a big problem in the 80s/90s or so but apparently it’s still happening, at least with subpar builders.

throw0101a 4y ago

> Interesting, why isn't the moisture on walls behind insulation ever an issue on new construction? Newer building codes have started to mandate more external insulation: * https://www.buildingscience.com/documents/insights/bsi-001-the-perfect-wall https://www.buildingscience.com/documents/insights/bsi-001-t... Depending on the climate zone, up to half the insulation may be mandated to be on the outside (behind some kind of cladding (brick, stucco, siding) to protect it from UV and bulk water). Per the above article, by having the outside be insulation, your interior structure is kept warmer, and so condensation is less likely to occur. Do a search for "Joseph Lstiburek" and "Matt Risinger", who have lots of articles and videos on building science. * https://en.wikipedia.org/wiki/Building_science https://en.wikipedia.org/wiki/Building_science