I live in south central arkansas. I am building a 32 X 72′ shop out in the country. The shop has a 4″ concrete slab with a 16 X 12″ perimeter footer with rebar and wire mesh reinforcement. I have 3 course 8 X 8 X 16 block wall which has been grouted in the cavities which have rebar in them. I also gouted the cavities which i placed the tie bolts for the 8′ 2 X 6 walls. Would grouting the remaining cavities pro vide any insulating benifit?
I am thinking of putting a rigid foam insulation over the block portion of the walls. I don’t know what type or thickness would be the best or most cost effective.
Thanks for any help out there,
Satrat
Replies
Grouting the remaining cavities would actually reduce (slightly) the overall insulating value of the wall. Air is a better insulator than concrete.
Solid grouting CMU cavities is a waste of time, material, and dollars if it doesn't provide you a needed structural benefit.
Dan said it ... air is a better insulator than concrete/grout .... which is why insulations work so well including the rigid insulation you mentioned putting in.
The best insulation you'd install depends on your location (i.e. weather), how/when you intend to use your shop, and what heating/cooling source you might have. That being said, though ... arguably, a 'typical' thickness might be 2 inches. You putting it inside or outside? What finish do you intend to use? Difficulty of installation and finish will often affect the thickness as much as energy concerns (that's why we normally don't see R-38 walls like in the ceiling.
Sorry ... I see your location ... do you intend to cool the shop?
Clewless thanks for the info on grouting. I do intend to heat and cool the shop with a cental unit, good thing about arkansas is we have 4-5 months during the year where the heating or cooling is not necessary at those times i use a big fan placed into the wall blowing out.
The rigid foam insulation will go on the inside of the blocks with construction adhesive then an OSB cover over that with a bare minimum of screws into the block to hold the strand board in place. I will probably use fiberglass insulation in the 8' stud wall that are going on top of the block.
Thanks, Satrat
The grout won't help insulate but it will keep termites out of the framing. Where I live (central North Carolina) the top course has to be made of solid masonry or, if cored blocks are used, the top course has to be filled with grout.
Mudslinger thanks for the info on grouting the block. I hadn't thought about termites coming up through the cavities of the block but we definately have our fair share of the little buggers here in AR.
Thanks Satrat
Note that to block the termites you don't have to fill the core all the way down, but (as Mudslinger suggests) just fill the top. Stuffing newspaper into the core is usually sufficient to support the grout, if you're reasonably careful.
Dan thanks for the information on grouting blocks makes perfect sense when you think about it.
Satrat