My friends are going to remodel the loft in their 1.5 storey home. They want to sell in the next couple of years, so this will be a DIY effort with minimal investment. I’ll be helping them.
The only insulation is fiberglass stuffed between 2×4 rafters. It’s completely black from filtering drafts for many decades. It seems worthless. The loft is definitely freezing cold in winter, and sweltering in summer.
What would you do? I’m not sure how much spray-foam would cost, but it’d probably be more than they want to spend. Any recommendations?
Replies
If only the rafters are insulated then insulating the knee walls will help.
I don't know if spray foam is a good idea on the rafters because there should be an air gap between the insulation and underside of the sheathing.
"I never met a man who didn't owe somebody something."
If you use a spray foam insulation, an air gap is not necessary. IMO, that's the way to go here.George Patterson
Spray foam would be several hundred dollars. About double what fiberglass would cost. But you don't need to take special steps to ventilate the roof, so that's a plus.
I'm not sure how much spray-foam would cost, but it'd probably be more than they want to spend. Any recommendations?
I have spray foam in my own house and think it's great. I strongly recommend it to all my clients. Roof ventilation is NOT required, so it's perfect for vaulted ceilings. It virtually eliminates airflow due to gaps, and outperforms fiberglass hands down. Also of importance to me is that it does not allow mold growth, etc, like fiberglass.
But it is NOT cheap like fiberglass.
Even though they think they'll sell the place in a couple of years, I would have them seriously consider the foam. With energy costs higher now than they've been in quite some time, the superior performance of spray foam could be a good selling point.
Also, goals sometimes change, and they might be in the house for longer than they think.
Have them get a bid from a local foam company to at least make an informed decision.
Spray foam is the most efficient method in this case- for HVAC purposes. It is understandable that the up front costs are greater. Maybe that might be recouped at sale time with a buyer who's in the know about such things, who knows.
However, the cost are going to be there for whatever insulation. Considering a 1 in. continuous ventilation space at the sheathing, they will need AT LEAST 8 more inches of insulation, fiberglass, blown, whatever, to become an efficient living space. One would need to consider also the added framing to accomodate drywall.
That said, I feel spray foam tight into a 2x4 cavity is an efficient way to go. Usually not a DIY project, but money well spent, IMHO!
Neither cold, nor darkness will deter good people from hastening to the dreadful place to quench the flame. They do it not for the sake of reward or fame; but they have a reward in themselves, and they love one another.
-Benjamin Franklin
as a very rough guide here in PA, you can figure about $1 per board foot for closed cell foam.
that is 1 foot square by 1 inch thick at about R-6 to the inch of thickness.
carpenter in transition