My basement's insides are completely unfinished. It has bare brick walls and bare concrete beams-vaults as the ceiling. I though of coating the walls and the ceiling with 2 inch thick plaster with the objective being that the house's ground floor won't be so cold in the winter. I thought of doing it myself with plaster since I do not have the budget for fibers, panels, gels, foams or any other insulation.
Can I buy a few sacks of plaster, mix it with water, apply a 2 inch coating and get a reasonable, yet inexpensive, insulation ? Would plaster make the ground floor less cold or would it be a complete waste of my time ?
Best Answer
According to Bon, plaster has an R-value of about 0.12/inch, so your plan will give you about 0.24. That little insulation is not going to be of any practical value (R-0.24 means you're stopping about 4% of the heat transfer). Comparatively, EPS or XPS has a value of 3.5-5/inch (stopping 72-80% of the heat transfer) and will help with keeping things warm.