Today we’re going to be adding insulation to an existing attic.
The home in question was built in the mid 1970’s, and presently has about six inches of fiberglass insulation on the attic floor, providing about R-20 of thermal value. With today’s attic insulation standards set at R-60, the homeowner will need to add about 14 inches of Atticat blowing wool.
Why add insulation to an attic that’s already insulated? Because this attic is insulated to 1970’s standards. In the 70’s, energy and electrical costs were relatively low, the economy was strong, and the Montreal Canadiens were winning Stanley Cups. So, it was no big deal having to put on a sweater before curling up under the covers, because hey, the Habs were winning hockey games. Today, the Canadiens wouldn’t recognize the Stanley Cup if it walked up and bit them on the butt, so there’s no celebratory mood to help warm your cockles. Furthermore, home heating costs are atrocious, while Justin Trudeau’s focus is on getting fitted for his dragon embroidered Changsha (traditional ceremonial robe) in preparation for his trip to China, because that’s what Chinese men wear every day, apparently, with the deficit issue far down his list of concerns.
So, we’re left to fend for ourselves, which means reducing our heating bills by bumping up our insulation levels. Why choose a blowing wool, as opposed to fiberglass batting, to insulate an attic? Because the blowing wool strategy provides the homeowner with longer arms, allowing them to distribute the insulation matter from a series of vantage points, thereby eliminating the risk of having to gingerly step across the truss joists. The suggestion to use the Atticat strategy is based on the element of P&P, prudence and probability. The safety relevance of the P&P is based on what’s referred to as ‘balance beam heartbreak’, which simply refers to the fact 40 per cent of gymnastic injuries are balance beam related. Considering this beam measures four inches wide, and is stepped upon by trained athletes, what are the chances of the average do-it-yourselfer making it safely across a series of truss joists that are only 1-1/2 inches in diameter? Unfortunately, official documentation regarding this action is limited. However, ‘prudence’ tells us the average non-gymnast homeowner should be avoiding the strategy of straddling joists as they place batts individually over the attic floor, because ‘probability’ tells us the resulting fall will drive one’s scrotum up into their body cavity.
So, with this vision in mind, cut yourself a couple of 16”x48” sheets of 5/8” plywood, or pick up a couple of 2×10 pieces of lumber, and toss them up into the attic beforehand. These will provide a safe walkway as you slowly manœuvre over the floor joists.
Step one to this project, ensure the attic space will be adequately vented. For this job, you’ll need to staple vent baffles, aka rafter mates, in between each truss. The vent baffles prevent the insulation and blowing wool from blocking air from entering the attic through the soffit. Then, make sure there’s adequate roof venting to create this necessary draft of fresh, outdoor air. The roof venting requirement can be satisfied by having an accredited roofer install a Maxivent type of product near the peak of the roof. Next, create an extended attic hatch tunnel by stacking 2×8 lumber edgewise along the perimeter of the hatch. This extended tunnel will prevent the blowing wool from falling through the attic hatch door. Since we’ll be requiring about 14 inches of Atticat blowing wool, use a tape measure to mark the 14 inch necessary depth along the truss webbing, or staple a series of Atticat paper rulers to the joists at 10 ft. intervals. In order to add R-40 of thermal value to this attic space, the amount of Atticat required will be based on the calculation that one bag of Atticat blowing wool will provide 49 sq. ft. of coverage. Be sure to watch the Atticat install video, and follow all instructions.