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Rim Joists Insulation – What Are They?

There are places in a home that are deemed critical to the energy efficiency and durability of a home. Rim joists are an example of such places. Even though they are an afterthought once construction is done, if correctly and carefully installed, they could help to reduce energy bills through a sustainable enclosure. If incorrectly done, they lead to moisture accumulation, mold growth and rotting. Rim joists are located between the top of the basement floor and the start of the first floor. However, in most cases rim joists are uninsulated. It is important to note that the rim-joist areas are where many building components such as the foundation wall, mudsill, rim joist and the subfloor come together. That alone can give you the picture of why it is so critical to prevent damage to the rim joists at all costs. The most effective way to make sure that the rim joist last longer is by insulation.

Benefits Of Insulating Rim Joists

Lower Utility Costs And Contribute To Energy Savings

Most homeowners would love to reduce the cost of living yet maintaining the standards of living and levels of comfort they deem sufficient for them. But that can only be a dream if your home insulation is not properly installed. Unsealed and uninsulated rim joists, encourage air leakages hence creating an uncomfortable temperature variation in your home. As a result, your air conditioner and heater are forced to work harder to maintain comfortable levels of temperatures. Insulation and sealing of rim joists, does not allow air leakages hence maintaining comfortable temperatures and saving on the energy used to heat the room and more so cutting down the cost of living.

Reduces Moisture And Mold

Houses breathe from the basement up. If there is moisture build up in the rim joist area, there are increased chances of mold growth and rot. This will dramatically affect the air quality of your home and pose health concerns. But well-sealed and insulated rim joists will eliminate the probability of mold growth through preventing moist air from entering the rim joists.

Stop Pests

Pests such as rodents easily find spaces through uninsulated rim joists and make them the pathways of getting into your living space. Sealing will cover the cracks and the penetrations.

How To Properly Insulate Rim Joists

There are lots of insulation supplies that one can use to insulate rim joists. But one thing to consider when choosing the type of supplies is permeability. The material used should be completely impermeable to moisture and air.

Though a lot of people once used fiberglass to insulate rim joists, it is no longer recommended. Fiberglass batts are permeable and do not protect the rim joists from humid air. Thus when it’s cold, condensation may occur causing mold then rot.

The best type of material recommended is the spray foam. Both rigid foam and polyurethane foam are air impermeable hence should be used to insulate the interior of rim joists. Most home insulation companies prefer spray foam to rigid foam since it is easy to install and reaches even the most awkward places. Moreover, it is cheaper to install.