- posted 7 years ago
We recently bought a 160-year-old farmhouse that has 2inches of rock wool between the joists in the attic. We would like to add fiberglass batts to increase the R-value. Can we simply lay the batts over the rock wool? There is not a vapor barrier, and we have been advised not to install one as our home does not have an air-exchanger (it is old and drafty--that IS our air exchange!). Or, do we need to remove the rock wool, put down faced batts first and unfaced over that? We really would prefer to leave the rock wool in place, but we do not want to have a moisture disaster in our house. Thanks for any advice!