Green Remodeling Tip: Fiberglass Insulation in the Basement is a Disaster Waiting to Happen

More and more these days, contractors have been fitting basements with fiberglass insulation.

While it’s a great idea to make your basement more comfortable — and your house more energy-efficient — by insulating your basement, you want to choose the best insulation possible. Fiberglass is not necessarily the best choice for your basement.

But it can’t be that bad if so many people are using it, right? Betsy Rathburn from Innovative Basement Systems, a company that has been solving wet basement problems in MN since 2004 has a different story to tell. Having seen a lot of damage and mold problems caused by the use of fiberglass in basements, she offers a few words of advice you should consider before you choose the insulation material you will use in your basement:

1. Fiberglass insulation works well if it stays completely dry. Yet, when placed against a basement wall, it will soak up the moisture that seeps through the concrete, and as it does, it loses R-Value. Not to mention the fact that it gets completely ruined in the event of a basement flood.

According to Betsy, basements in Minnesota and North Dakota have a history of flooding in spring months when the snow starts melting. “It just doesn’t make sense for homeowners in this area to choose fiberglass for their basement insulation.”

1. For fiberglass to work well it needs to be fluff and evenly spread throughout the wall cavity. It will however settle, especially when water creates gaps in the insulation blanket. Over time, this gap can significantly widen, decreasing the effectiveness of the insulation. This causes a decrease in home energy efficiency and costs money – both on heating costs and on eventually replacing the insulation.

Also, when you cut holes into insulation for wiring, plumbing or to hang heavy fixtures on the concrete walls, the insulation becomes far less effective, because of energy losses through these gaps. With all the money you pay to heat and cool your home, you might as well not install any insulation at all – though a better solution would be using a more efficient, more effective basement insulation option.

1. Fiberglass itself is inorganic, but it frequently has a paper facing that can make it – and your entire basement – at risk for mold growth. If your basement is vulnerable to water, it’s vulnerable to mold, and most basements in Minnesota and North Dakota have experienced some degree of water – whether it’s high humidity, a plumbing leak, or a full-fledged flood – in the past.

So what are the alternatives, if you don’t want to take a risk with fiberglass?

The U.S. Department of Energy recommends the use of rigid foam board for basement insulation, because this material is inorganic and will not absorb water. Attached directly to the basement walls, it will act as a vapor barrier and, if the basement has an internal perimeter drainage system, any moisture seeping through the concrete will be re-directed outside the home. Furring strips are then installed on top of the foam board, to hang the drywall.

An even better alternative to this configuration are pre-fab basement wall insulation panels, available through companies specializing in basement finishing and/or waterproofing. “Our company installs a panel made with R-13 foam board infused with graphite, giving the material a higher R-value per inch. It has embedded metal strips for hanging drywall, which are a superior alternative to wooden furring strips.

Our customers,  love the comfort, the energy savings and the fact that their insulation won’t get ruined the next time a pipe leaks or the basement floods for any reason.”