Moisture barrier is installed. Although there are advantages to both it all comes down to the issues you are trying to solve.
Automatic-opening crawl space vent.
Vented vs sealed crawl space. Compared with the leakiest worst case scenario however closing up a crawlspace can make quite a difference. Crawl Space ventilation is the answer that contractors have historically given to the issue of crawl space humidity in homes. A vented dirt crawl space raises your heating and cooling cost 15 and up 25 every month and makes it very likely you will have a big expense for mold removal andor rotten wood replacement.
A crawl space encapsulation otherwise known as a sealed crawl space is a better alternative to vented crawl space which provides the following functions. Vented crawl spaces dont really work as promised. Always-open crawl space vent.
The dirt ground that makes up the floor of your crawl space is full of moisture. This defeats the purpose of ventilation as moisture is brought into the crawl space through vents instead of being removed. Compared with the minimum ventilation allowed by code the energy savings from not venting may be small in a well-built and well-sealed home.
The question now becomes what are you going to do about it. They should be treated as partially conditioned space to control moisture and decrease energy use. Whats better vented or sealed crawl spaces.
I find it very confusing to read and hear conflicting advice on crawl space. This article describes best practices as well as common codes and standards for venting or not venting the space beneath buildings. Generally this involves installing vented openings in cross-sectional area equal to 1150 of the floor area served.
Vent vs air seal different ways to do insulation vapor barriers vs not etc. Mine currently has some moisture and has a 6 square hole in the exterior wall and 2 large 3 square openings to the basement next to it. They never exceeded 50 percent RH.
While it may look dry looks are deceiving. Encapsulated crawl spaces are consistently better at controlling moisture that enters from the damp earth or from warm humid air that would otherwise intrude from the outdoors. Crawl Space Ventilation vs.
Will natural ventilation adequately remove the moisture or should you have your crawl space sealed also known as encapsulated. A vent on one side allows a breeze to enter your crawl space and carry the stagnant air out through another open vent on the opposite side. Should you ventilate the crawl space close off crawl space vents install crawl space vent fans or dehumidifiers or what.
This moisture will eventually cause issues as well. Most crawl spaces are vented to the outdoors but over the past decade encapsulating the crawl space as shown below has gained favor among builders of green and energy efficient homes. Today crawl space science looks a lot different.
More recent thinking from building scientists dictated that crawl spaces should be sealed insulated and installed with a vapor barrier. In addition the vents allow allergens dust and bugs to enter your home. Of course sealing your crawl space vents isnt going to solve all your issues.
Crawl space insulation is added according to site conditions. In a similar test in Flagstaff Arizona – a colder dryer climate – vented crawl spaces stayed below 70 percent RH but sealed crawl spaces were less. Standards in home building have changed a lot over the years.
Along with insulation a sealed crawl space can give the homeowner around 18 in savings for heating and cooling costs. Unless the floor between the house and crawl space is totally sealed with polyurethane foam then the building occupants will breathe some air from the crawl space. Closed encapsulated crawl spaces have lower relative humidity which means less rot better air quality and fewer pests.
Breathing nasty crawl space air makes people sick. The main thing to take-away. Ventilating vs Sealing a Crawl Space.
To protect your crawl space a closed or encapsulated crawl space is now preferred to an open or vented crawl space. A debate ensued and because some builders are slow to change many foundation vents continue to be installed. Vents are sealed.
The theory is that air circulates through the crawl space to dry it and the humid air out. Crawl space moisture sources reduced or eliminated. Its often seen as the best way to eliminate the moisture problems that often result from vented crawl spaces.
So your crawl space has moisture. Current best practices compare crawl space venting versus crawl space dry-out seal-up as a conditioned.