Insulation saves energy and money

Press, 13 April 1978, Page 12

Insulation saves energy and money

Most homes built ia the days when energy was more plentiful and cheap do not have enough insulation — but insulation can be added to any house, even if some already exists. Insulating an attic floor, w here savings generally will be greatest, usually can be done by fhe home owner himself Other home tmprovemt ts that will save energy are to insulate sidewalls, add storm windows and doors, install weatherstripping, and caulk

around window and door frames. In the heating season alone, adequate insulation in the attic floor generally will save up to 20 per cent on fuel bills. In your case, the percentage of savings will depend upon how much insulation you had before you added more, the attic area of your house in relation to wall area, number and size of windows and doors, and whether you have storm windows and doors and good weatherstripping. It has been estimated

that if you live in a region of relatively mild winters and have no ceiling insulation, an investment in 15cm (6in) of attic-floor insulation will be returned by fuel savings within one year. The exact amou of money you will save is affected, of course, by the rates you pay for fuel and electricity. However, no matter what those rates are, if you make energy-con-serving improvements to your home now, you can expect even greater future

dollar savings as energy costs rise with inflation. The following do it yourself advice on home insulation was supplied by the Federal Energy Administration of the United States but is equally as relevant and helpful to conditions in New Zealand. The insulating materials for use in existing homes include: Mineral wool, cellulose fibre, foams (polyurethane, polystyrene or urea formaldehyde) and reflective foil. Mineral wool, either fibre glass or rock wool, is among the most widely used type. It is available in these forms: Blankets — Rolls of insulation, with vapour barriers or without (unfaced). Batts - Similar to blankets but cut into 1.2 m (4ft) or 2.4 m (Bft) lengths. Pouring insulation — Loose insulation meant to be poured into attic floors. Blowing insulation — Contractors use pneumatic equipment to blow the insulation into place in ceilings (attic floors) or walls. To insulate an attic floor where there is no insulation, lay batts between the joists. They do not need to be stapled. The vapour barrier must face down. If some insulation already exists, add a layer of batts or blankets on top of the old. It is important that the new insulation not have an effective vapour barrier. Preferaby, the new insulations should be unfaced — that is, have been made without a vapour barrier. If unfaced material is not available, use the vapour-barrier type but remove the vapour barrier or slash it freely with a knife (then install the insulation with the slashed surface down). Pouring insulation also can be used to insulate an attic floor. The ’ insulation is simply poured out of a bag. then leveled with a

rake or a short piece of board. To insulate a wall, fit the end of a blanket snugly against the top piece of framing. Working down, staple the flanges to the sides or the faces of the studs. (With aluminium foilfaced blankets, staple to the sides to create an air space, which is necessary for the heat-reflective value of the foil to be achieved). Space the staples about Bin apart. Cut the blanket to fit tightly against the framing at the bottom. If more than one piece of blanket is used in the same stud space, butt the ends tightly together. The vapour barrier must face the side of the wall that is heated in winter. To insulate stud spaces that are narrower than normal, cut the insulation about lin wider than the space to be filled. Staple the remaining flange, then pull the vapour barrier on the other side to its stud and staple through the barrier. Walls can be insulated with unfaced blankets and a separate vapour barrier, either 2-mil-or-thicker polyethylene sheeting or foil-backed gypsum board. Keep polyethylene taut as you apply it. Staple it in place. Instal insulation behind pipes and ducts (to keep them warm) and behind electrical boxes. Spaces of this sort also may be hand-packed with loose insulation. To get loose wool, pull pieces from a blanket. Cracks and very narrow spaces, such as those around window framing, should be stuffed by hand with loose insulation and covered with a vapour barrier. Masonry walls, basement walls and the like, are insulated by first fastening 1 x 2,2 x 2, or 2 x 4 furring strips in place vertically. They should be placed 16in or 24in from the centre of one strip to the centre of the next. With Ix2 furring, use special- '‘masonry wall” blanket insulation (unfaced material which should be covered with polythylene or foil-backed gypsUm board to provide a vapour barrier). To insulate floors above cold spaces, push the batts or blankets between the floor joists from below, vapour barriers up. To support the insulation, lace wire back and forth among nails spaced about 2ft apart in the bottoms of the joists. Pieces of blanket cut to size should be fitted, vapour barriers in along the sill at the ends of the floor area. First, calculate the overall area to be covered — multiply the length by the width. Then adjust this number to allow for the area taken up by joists or studs. If joists of studs are 16in apart, ■ multiply by .90. If they are 24in apart, multiply by .94. The

answer is the number of square feet of insulation you will need. If you are going to use pouring insulation in an attic floor, usually there will be a bag label that will tell you how many square feet a bag of that particular insulation you will need. Divide that number into the number of square feet you want to cover, and you will know how many bags to buy. Tools required for the job: Sharp knife to cut blankets and batts. A ser-rated-edge kitchen knife works well. straight edge to cut along — rigid metal rule or a short length of board. Measuring tape if you do not use a metal rule as a straight edge. Rake, or other tool, to push or pull blankets to the eaves edge if there is not much headroom. Walk boards, several pieces of fin utility-grade plywood, 12in to 16in wide and 4ft long, or something similar. If you step on the top ceiling surface, your foot will plunge right through — so use walk boards. Portable light, such as a mechanic’s trouble light or a clamp-on photographic light. An extension cord, too. Staple gun for applying wall insulation. Precautions to take: Treat electrical wiring with care. Don’t try to pull it or bend it out of the way. Even in the cleanest of homes, attics tend to be dusty. Wear old clothes. Insulation fibres can cause temporary skin irritation, so wear work gloves and loose-fitting clothes, including a longsleeved shirt. Be wary of nails that stick through the roof sheathing above your head. Don’t smoke in the attic. Do put the vapour barrier side of insulation blankets and batts down in the ceiling — even if, when adding new insulation on top of old, you have slashed the barrier to let moisture vapour pass through. Do insulate under attic walkways, pulling or pushing the insulation as needed. If much of the area is covered with flooring, you might need to remove some boards for access to the space. • Do work from the outer edge of the attic space toward the centre. You will be able to do whatever cutting and fitting is necessary at the centre of the attic rather than near the eaves, where there is little headroom. • Do insulate the top of the attic scuttle panel. Staple directly through the edges of the insulation into the panel board. • Do hand pack insulation around pipes and electrical cables that pass through the attic floor. Stuff openings around interior chim-. neys.

• Do patch the vapour barrier of wall insulation if it has been torn. Strip a piece of vapour barrier from a scrap section of blanket or use polythylene, taping the patch to secure it. • Do paint interior walls as a substitute vapour barrier if you are having a contractor install blown insulation. Use two coats of vapour-resistant paint and brush them in well. (Paints vary widely in the rate at which they allow water vapour to pass through. Ask a paint dealer about the “perm rating’’ — vapour permeability rating — of the paint he carries. A rating of 1 perm or less for primer and finish coat combined is considered good. If the dealer does not know about perm ratings, ask him to check with the manufacturer.) (Continued on next page.)

The diagram shows where insulation goes. The numbers on it are keyed to the list below: 1. Ceilings with cold spaces above. 2. Exterior walls. The short walls of a split-level house (2A) should not be neglected. Walls between living space and unheated garages or storage rooms should be insulated, too. 3. Floors above cold spaces—vented crawl spaces, garages, open porches, and any portion of a floor in a room that is cantilevered beyond the wall below (3A).