Underfloor insulation increases the comfort of your home. Even though you can insulate under a second-floor surface to isolate the degrees — blocking out sound and allowing you to heat the 2 floors separately — in which you will observe the effect most is above unheated areas. Uninsulated or poorly insulated flooring over crawlspaces and basements lose a tremendous amount of heat and create bare feet cold in the winter. So long as you have enough room to access the floor joist framing, installing insulation under the ground is a fairly simple remedy.
Squirt either caulk or expanding foam insulation in each hole or split in the ground. Fill voids around the surface of the wall, where the base meets the ground framing, and gaps around pipes and wiring or similar holes. Expanding foam works well in massive places while flattening will fill the smallest ones.
Assess the depth of the joist cavity. Standard joist spacing is 16 or 24 inches apart. Pick either fiberglass roll or batt insulation based on these specifications. That is, both rolled-form fiberglass and premeasured batts can be found in either width. The deeper the joist cavity, the thicker batt or roll you’ll be able to use, ultimately meaning greater R-value — heat transfer resistance.
Begin at the far end of the floor joists and work down the length of every pit between joists. Insert one end of a fiberglass batt or the loose end of a metallic roll in the initial joist cavity, tight against the base wall in the end. If the fiberglass is confronted — with a special paper backing on one side of the insulation — stage that aspect up towards the ground surface above.
Pull out on the insulation marginally immediately after inserting it. Think of cotton candy — the fluffier the material the better it is. A slight compress helps the insulation fit up in the cavity and a tiny tug down on the material will allow it to better fit the cavity, making a friction fit, as well as optimizing the insulation R-value.
Move marginally down the row, then inserting and fluffing the upcoming few feet of material. If the insulation doesn’t want to stay on its own, or in case a protected installation is of special concern due to end, animals and such, add special insulation hangers each three to six feet to get additional assistance. Fashioned like a wire coat hanger, these insulation supports simply compress slightly to fit in position between the joists. Once released , they form a rigid anchor that prevents the insulation from falling entirely free.
Cut either fiberglass rolls or batts to fit as necessary. If the insulation needing cut is already partially installed, hold the insulation up to the close of the joist space and approximate the amount of material needed. Make it a little longer as opposed to too short for the space involved. Working with insulation nevertheless to be installed, measure the joist space length and move to both sides of the insulation. Compress the material and use a utility knife or scissors to cut through it. A straightedge makes an excellent cut guide.
Join parts of insulation when you run from the middle of a row. Completing the edges together tightly to avoid air gaps. Install an insulation hanger, if used, on the side of the joint.