For conversion to a non-ventilated crawlspace, what is the proper installation methodology? What R-Value is added by installing on the cinderblock walls? Should the current fiberglass batt insulation installed under the floor be removed?
Answer:
If you are looking to attach reflective insulation all the way around the crawl space – it would be recommended that you attach a 1 x 2 furring strip to the concrete block using adhesive or mechanical fasteners. Then attach the reflective insulation to the furring strips using staples. The horizontal R-Value you would obtain using this method is about an R-8 including the internal air film.
If the fiberglass batt is in good condition and there in no moisture building up in the batt (the batts will go black if there is moisture buildup) then you can leave them in place. However, if they are black or very damaged, they should be removed.