Cellulose Insulation Advice

One of the areas of my home which need addressed insulation wise is a 11×11 attached dressing room that was built on. It was built butted up against the exterior brick of the home, which is by far not the best method I know.

The problem however is in the insulation. It seems to be an older fiberglass bat insulation that is at best a little over 1” thick. This leaves a space of around 2” or more behind the craft paper that’s uninsulated.

The room has awful air infiltration which considering the sub par at best insulation I can understand why.

What I need to know is if I can simply drill out the existing wall covering (which is drywall over paneling) and blow in cellulose to fill the wall cavity fully, even at the expense of completely compressing the sub par fiberglass.

If the answer is yes, can I do the same with the ceiling? I have not checked yet to see what kind of nightmare it may be.

SECOND QUESTION which is on the same lines as the first. Blowing cellulose into floor joists within a crawl space environment? My understanding is that the product is indeed safe to be used in this manner. I’ve got.. hmmm.. 4 different crawl spaces which I want to insulate.

Two of the crawl spaces are no doubt over dirt where as two of them are over concrete slabs where the house was expanded. There are no moisture issues under any of the crawl spaces.

Beyond just the R value insulation needs, we’re also combating a shockingly large scale air infiltration issue. Cellulose is great not only for price but also to block air flow and noise so I thought it to be the best solution.

So what say you? OK to blow into a poorly insulated wall and/or ceiling and compress the fiberglass? OK to blow into floor joists within crawl space areas?

I should also mention that the crawl spaces have fiberglass insulation in them which has all but fallen out over the years due to improper installation and is now considered worthless.

Also it’s a nice home for the Brown Recluse which we had issues with when we first moved in. Two years later, we don’t get near as many on the glue traps as we once did. ;)

-- Planting Daylilies in Kentucky, zone 6b