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Best way to improve attic insulation on a budget

Epona262

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Oct 8, 2025
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My roommate and I rent the upstairs of an old duplex and the attic above us is barely insulated. We're trying to keep heating costs down this winter and I can get rolls of fiberglass cheap from a co-worker. Is it worth laying them over the existing blown-in or should we pull the old stuff first?
 
If the old blown in is dry and not moldy, just lay the fiberglass rolls right over the top, no need to pull it out. Make sure the batts run perpendicular to the joists to cover gaps and don’t compress the blown in, since that kills its R value. I think it’s a cheap, effective way to bump up insulation without a full attic overhaul
 
If the old blown in is dry and not moldy, just lay the fiberglass rolls right over the top, no need to pull it out. Make sure the batts run perpendicular to the joists to cover gaps and don’t compress the blown in, since that kills its R value. I think it’s a cheap, effective way to bump up insulation without a full attic overhaul
I should be able to get the rolls from my coworker this week and plan to put them in over the weekend. Do you think using two layers of batts is too much, or is it okay as long as I avoid crushing the blown-in insulation?
 
Thought I'd jump in. Two layers of batts on top are great. More thickness means better performance! The crucial rule here is to avoid compressing the insulation. It must remain fluffy to trap air effectively. Lay the new batts perpendicular to the ceiling joists for maximum coverage. Just be sure to maintain proper clearance around any heat sources, like chimneys or recessed lights, and keep the soffit vents clear with baffles. This cheap boost should really help your heating bills!
 
the comments here aced it. just wanna add something small but important, make sure you always wear protective gear, including a long sleeved shirt, pants, gloves, and a dust mask or respirator when working with fiberglass to avoid skin and respiratory irritation
 
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