Attic Access Hatch
In most homes, air leakage through building penetrations is something that is hard to avoid, but there are some places in the home where excess air leakage can be controlled.
In homes that have an attic and crawlspace, there are usually access hatches that are located inside the building interior. Most of the time the attic access is located on an upper floor ceiling or wall, and the crawlspace access is in the floor of the main level, usually inside a closet. Up until the recent past, insulating and air sealing these access points was not required, and in many older homes these are areas where significant air leakage and thermal loss can occur.
Air leakage in a home works under the concept called the “stack effect”, or “chimney effect”. This concept explains how air moves through a home, similar to how a chimney works. Air comes into the home at the bottom, and leaves the home at the top. Therefore, houses with a crawlspaces and attics with unsealed access hatches will usually experience air leakage through the crawlspace access hatch from the crawlspace into the home, and through the attic access hatch from the home into the attic. This could lead to several issues including:
· Poor indoor air quality when dusty moist crawlspace air enters into the home. This could bring air pollutants such as dust, and mold spores into the home.
· Mold growth issues when moist air from inside the home leaks into the attic, allowing water to condense on cold surfaces during cold temperatures, which provides a moisture source for mold growth.
· Ice damming on roofs for homes in cold snowy climates when warm air from the home leaks into the attic, which can allow the snow on the roof to melt, and then re-freeze at the bottom of the roof edge.
· Drafts and uneven temperatures inside the home
· Increased energy bills
If you live in a house built prior to the early to mid-2000’s, chances are that your access hatches are not adequately insulated or sealed with weather-stripping. If this is the case, upgrading the weather-stripping and insulation on the hatch covers is an easy project that can be done with materials found at the local hardware store or building center. The video below explains common techniques on how to insulate and weather-strip an attic access hatch. These same techniques can also be applied towards a crawlspace access hatch.