Eco-Saturday: Insulation

If you have a basement with open rafters, installing fiberglass insulation is a relatively simple DIY project that will shrink your home’s environmental footprint — and your power bills. Here’s a quick how-to:

Before. Look at all that empty space waiting to be filled!

Start by gathering your materials. You will need: kraft-faced insulation; work gloves; a dust mask; a tape measure; a utility knife; a staple gun; and staples. A yardstick or other straight edge is also helpful, and at my dad’s recommendation, I seized the excuse to buy a new power tool — an electric staple gun, which cost $30 and made the project a lot faster and easier. Note: Fiberglass can hurt your skin and lungs. At a minimum, wear work gloves, a dust mask and long sleeves for this project. Goggles are also a good idea, especially if you don’t wear glasses.


A couple of notes on insulation: Measure the distance between your joists to make sure you buy the right width. Also, buy an appropriate R-value. In general, the higher the number, the better, but don’t buy insulation that’s so thick you have to squish it to install it, because compression will compromise its effectiveness. I decided R-13 was sufficient for my purposes. (More on this below.)

Be sure to get insulation with kraft paper facing. Unfaced insulation is cheaper, but it’s harder to install and requires a separate vapor barrier.


Starting in one corner, measure off a section you want to insulate and cut a piece of insulation to that length. I kept my sections about three or four feet long to make them manageable.

To cut insulation, lay it paper-side-up and use your hands and knees to compress it as much as possible while you cut through it with a utility knife. (It will fluff back up once you let go of it.)


Unfold the edges of the paper, move the insulation into place with the paper side toward you, and staple the edges of the paper to the joists on either side. Most instructions say to split the insulation and tuck it loosely above and below any wires or pipes in your path rather than tucking all of it up above the wires — which can compress it — but I like to fix stuff myself, so I prefer having instant access to the electrical and plumbing systems. To that end, I chose an R-value low to fit above most of the wiring and plumbing without being compressed.






If you can’t afford to do the whole project at once, pick the coldest floor in the house and start there. In my case, that was the bathroom and kitchen area.