I am replacing the bathtub in my master bathroom. The house is about thirty years old and I would like to upgrade the insulation in the wall behind the tub. What choices do I have besides the traditional pink fiberglass and what do you recommend?\
Thank you for your advice…love your column.
Thank you for the great question.
You have a few choices. Obviously, like anything, the quality will increase as the price increases. The pink is the lowest. It is the bare minimum that building code will allow, but is really not that effective and requires a plastic vapour barrier on the WARM side of the wall to complete the system. This can be difficult to install properly and lead to drafts and condensation and mould growth.
The second choice is mineral fiber insulation, a much more pleasant product to work with, first of all. Much more rigid in its shape, it fills the wall cavity much better and will not droop over time. It is easy to cut using a bread knife and is not itchy like the fiberglass. This is my first choice for a budget installation. It costs about 25% more but its benefits are well worth it. Still requires the vapour barrier though.
Finally you have the option of the two part urethane spray foam insulation. This is available as a DIY kit, or can be hired out to a professional spray foam installer. The base price for the contractor is about $600. They won’t start the truck for less than that, but that gives you an installation of about 600 board feet of product; enough to do the bathroom wall and probably all the basement headers in your home…also a great investment. The DIY kit is handy, works ok, doesn’t have as high quality a product, or great a yield, and doesn’t install quite so cleanly, but it still costs about $600. Either way you go, it’s a far superior end product compared to traditional batt insulation. Plus, with a bonded foam product you don’t need a plastic vapour barrier…the foam is both a moisture barrier/air barrier and insulation in one…What A Deal!!!
Whichever way you choose to go, swapping out the old insulation is a great idea. Thirty years of dirt and moisture and god knows what else is enough to knock the efficiency out of the old fiberglass, plus even the new pink is more efficient than that made even 15 or twenty years ago. So for the cost of a bag of insulation, might as well do it while you have it open.