With the weather warming up again, I'm rushing to accomplish a home project of refreshing the insulation in the attic. Last year, we suffered through the summer with the temperatures in the house reaching up to the low eighties while it was in the upper nineties outside. I don't want to experience what will happen if the temperature goes above 100.
I spent a good chunk of time last year insulating part of the house, but I missed the area that was absorbing the most heat. The house was properly insulated a while back, but the existing fiberglass insulation has settled since then. Rather than piling on more fiberglass, I'm leveraging mineral wool insulation, which is resistant to settling, doesn't absorb water, and doesn't burn the same way as fiberglass (it has to get above 2000F before there's a problem).
Mineral wool insulation is about twice the cost per square foot compared with fiberglass. Rather than completely replace the existing blown-in fiberglass insulation, I'm moving it to make room for the mineral wool batts. Using the existing insulation to fill in some of the rafters as well as around the vents and pipes coming through the ceiling will reduce the amount of mineral wool insulation that I'll need. That being said, due to the mismatch between the width of the insulation (24in) and the width of the beams(19.25in), I'm going to end up with long and thin pieces of mineral wool that I can use to fit around hotter areas (like the water heater and the stove vent).
The goal is to raise the R-Value (the standard measure for insulation effectiveness) from an estimated R-10/R-15 to R-30. Hopefully, I'll be able to finish the hottest areas before Easter...