Is there an R-value and depth reference chart when blending lose-fill cellulose and loose-fill fiberglass ?
What happens when you have to dig up a base layer of R20 cellulose to get work done and mix it together with an upper layer of R20 fiberglass. I think its okay because there is a vapor and thermal barrier in place but I am undecided how to top up my salad.
Should I top up with R20 ? Fiberglass ? Cellulose ?
Thank you from Toronto, Ontario
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Replies
Pictures of churned up R20 cellulose and R20 fiberglass ( insulation salad ) resulting from my work in the attic.
- rebuild leaking fan ducts and remove mold.
- install stainless steel mesh in the rain screen to deter mice
- add more soffit ventilation
- replace fiberglass soffit plugs with rigid XPS
- insulate exterior wall plates with rigid XPS
- Seal and insulate the ceiling joint to top plate with rigid XPS.
- Seal a few light fixtures
Built in 1997 with vapor barrier. Zone 5 / 6. R60 recommended.
We do experience extreme cold so "low density" insulation may allow air to circulate between the top of the ceiling and the attic. Therefore, I lightly tamped down the first 3.5 inch's between ceiling joists and will spread the rest over top with a rake.
I would like to add R20 to the top of this approximate R30-40 mixture and considering loose-fill cellulose.
The R value of your blend will vary with the concentrations.
You may find it easier to use an insulation blower, either fiberglass or cellulose. They can be rented.
You also would be well served to look at local folks who do this all the time.
While you have things open, I trust you have sealed up holes from wiring and similar penetrations.
Cellulose has more R value per inch, but is more likely to settle and has a bit more dust to deal with
(hope you have been good about using a good mask while disturbing the insulation)
If you did have any rodents or insects, you may want to remove some or all of the insulation which is contaminated.
You can find a leaf vacuum with a zipper in the collection bag that should let you tackle some of this for transfer into large bags for disposal should you want to do some as a DIY.