Permanent Protection: Spray-Foam Vs. Fiberglass Batt Insulation

Isolating your home from the outside weather is a critical step toward keeping your heating and cooling bills manageable. The insulation inside of your walls is a key part of protecting your home environment, but some forms of insulation will leave holes in your protection. For the best, most durable insulation, you should choose spray foam over fiberglass batts.

Fiberglass Batts

Typical insulation consists of strands of fiberglass that have been spun into a slab of lightweight, low-density material which is several centimeters thick. This material is then cut into "batts" which are strips of material wide and long enough to fit between the studs in your home's frame.

When you press a fiberglass batt in between studs in the wall, you may be able to get decent insulation in most cases, but over time that insulation can degrade. Because batts go in as a limp sheet of material, gravity can force the material to sag over time. You have no way of knowing what is happening, but as your insulation sags, a gap is left at the top of your walls. You may also have holes in your insulation where you have thin cracks between studs in your wall. Because it is hard to push insulation into these cracks, it is easy to overlook them during insulation.

A final worry when you install fiberglass insulation is the threat posed by insects. Ants and other critters can carve off bits of insulation and carry them away to use as material for a nest. Over time, such harvesting can leave holes in your insulation envelope. 

Spray-Foam Insulation

Spray-foam insulation uses an entirely different insulation method. Installers use a nozzle to spray a liquid foam into your walls. This liquid rapidly expands and permeates the small cracks in your walls. Once this foam solidifies, it will create a rigid block of insulation. The tiny air pockets that get trapped in the insulation as it expands act as an effective barrier to the outside world, and because you have a solid barrier, you don't have to worry that it will sag overtime. Furthermore, insects can't carve out pieces of your insulation, so your insulation should stay intact for years to come. 

If your insulation deteriorates over time, you might start with acceptable heating and cooling costs, but as leaks develop in your walls, you might find that your costs get ever higher. In order to seal off your home permanently from the outside world, you need an insulation barrier that will remain intact for the long run.