I have a certain smell coming from the crawl space. According to the person who built the house, cuprinol or pressure-treated sills or beams were not used. However, I am considering creating a slight negative pressure in the foundation to see if it improves the smell in the living area.
The house is 13x7 meters with a heart muscle. The crawl space thus consists of two rooms. It is bedrock exposed and concrete as the "floor." I have sealed the foundation, installed a dehumidifier, and continuously monitor the humidity.
Roughly calculated, the volume is 13x7x0.8m = 72m3
1) How powerful does the duct fan need to be?
2) How should I think about the routing of the duct, vents, etc.?
The house is 13x7 meters with a heart muscle. The crawl space thus consists of two rooms. It is bedrock exposed and concrete as the "floor." I have sealed the foundation, installed a dehumidifier, and continuously monitor the humidity.
Roughly calculated, the volume is 13x7x0.8m = 72m3
1) How powerful does the duct fan need to be?
2) How should I think about the routing of the duct, vents, etc.?
You seem to have everything in good order there, unlike at my place where the builders threw down all sorts of junk while they were building.
As long as it's reasonably sealed, it doesn't take much to improve the situation. I have a 14W bathroom fan that runs constantly and ventilates the crawl space. It has completely eliminated the earth cellar smell that sometimes could be felt in the bedroom and living room and lowered the radon from 200-400 to under 10.
As long as there are holes between the sections in the heart wall, it creates the same negative pressure throughout the space, which I guess makes the difference; air prefers to go down rather than up. If you have strong negative pressure inside the living area, you might need to choose a more powerful fan. But ventilating large volumes of air brings other problems; it draws in moist air from the house or moist air from the outside.
This is what I've learned and my own practical experiences.
As long as it's reasonably sealed, it doesn't take much to improve the situation. I have a 14W bathroom fan that runs constantly and ventilates the crawl space. It has completely eliminated the earth cellar smell that sometimes could be felt in the bedroom and living room and lowered the radon from 200-400 to under 10.
As long as there are holes between the sections in the heart wall, it creates the same negative pressure throughout the space, which I guess makes the difference; air prefers to go down rather than up. If you have strong negative pressure inside the living area, you might need to choose a more powerful fan. But ventilating large volumes of air brings other problems; it draws in moist air from the house or moist air from the outside.
This is what I've learned and my own practical experiences.
Have you just placed the bathroom fan against an outer wall in the crawl space? You haven't installed any spiro?
I already had a ventilation pipe that goes from the crawl space up to a cap on the roof, it's probably a 110mm plastic sewer pipe (was it cheaper than spiro in 1972?), so I installed it there.D Derbyboy said:
Whether the chimney effect helps the flow or if the long pipe restricts the flow, I don't know, but if it works, it works.
Okay, so you are pulling air from the living area down to the crawl space and then through a 110-pipe up to the roof?
It is probably correct if you simplify it, but the flow from the living area is strongly limited. All rooms that have had their floors renovated have been meticulously sealed against the outer walls so that air does not move there. Some small leaks may exist, but it should still be more open to the crawl space from outside.
I would assume that most of the airflow goes from outside into the crawl space; there is a 32mm pipe for cable passage that is open out from the foundation, and probably some flow at the hatch and other small leaks.
I would assume that most of the airflow goes from outside into the crawl space; there is a 32mm pipe for cable passage that is open out from the foundation, and probably some flow at the hatch and other small leaks.