Hey everyone! I'm planning to blow in some new insulation in my attic and I'm a bit unsure whether I should remove the old insulation that's been up there since around 2000 or just add the new stuff on top. The current insulation isn't more than 1-2 inches deep at most. I live in inland SoCal, where summer temperatures can often hit over 100°F for several days, but usually are in the 90s for a couple of months. Any advice would be appreciated!
4 Answers
I'm actually in the middle of removing my old insulation this weekend! The original stuff from 1978 was in bad shape, so I'm cleaning everything out, sealing the attic, and then blowing in new insulation. If your insulation isn't that old and doesn't show any issues, leaving it is fine, but just keep in mind you won't have great air sealing unless you address the old stuff too.
If the old insulation is in decent shape without any moisture issues or pest problems, you can totally just blow new insulation over it. Remember, more insulation is generally better!
You don't have to remove the old insulation unless there's pest damage, but air sealing your attic really makes a difference. If you want to really seal everything up, that removal is key. But if you're not ready to spend a lot for air sealing, adding new insulation will help, just know it might complicate sealing in the future because you'll need to take it all out again later.
If your old insulation is okay with no signs of moisture or pests, covering it is fine. Just keep an eye on sealing your attic well. I've usually added new insulation on top and it hasn't caused issues, but it really helps with heating and cooling costs. Just know that if you plan on doing major work later, like installing lights, it might be tough with all that extra insulation in the way.
Sounds like a big project! Just make sure to seal any gaps and look out for rodent droppings when you're working up there. It's definitely worth the effort!