I am applying 2′ x 8′ x 1 1/2″ styrofoam panels to the exterior of a concrete foundation wall. Supplier is sending out PL adhesive for this. I am concerned about the “Elsro” foundation damproofing harming the styrofoam, any thoughts on this……
Also I have to protect the styrofoam at and above grade with probably a parging. Not clear on how to hang stucco wire to foam. Thinking of 1/2″ PWF ply, anchored threw foam into concrete then wire and parging? Any experiences you folks can share would be appreciated.
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Jeff:
Not sure about your BC or what you inspector will allow, but if I were using PT ply over the foam board, I would paint and flash it, and forget the parging. The 1/2 inch may be more than necessary, depending on the height of the exposure.
There's a guy up this way who says just make sure the foamboard is well-attached, rough the surface with a wire brush, etc, and apply the parging directly to the foam. Has anybody tried this or seen anybody try it?
Good judgement comes from experience, and a lotta that comes from bad judgement.
Doc
I did something similar, applying a cementous coating called Thoroseal (I think) directly over 1.5 inch "blue board" insulation which had been glued to my concrete basement walls. The coating contained fiberglas particles to enhance its strength and bonding properties. After 18 years the coating visisible above grade is still holding up well.
I know that in our code, the top of the foam must be kept 2" below the bottom of the bottom plate to provide an inspection gap for termite tunnels, and the top of the foam must be beveled at a 45 degree angle for drainage. I use chicken wire and stucco. No problems yet, except with the termite treatment people, they will not give me a warranty claiming that termites just love to come up through foam, and after that it's just a shot hop the the house. Who knows?
Thanks for the info.....We do not have to worry about the termite problem up here. The foam is installed up to the sill plate. I will install a flashing on top of that. I was wondering how you attach the chicken wire to the foam ? Thanks
Jeff, I used Masonry nails with fender washers. Nailed through the foam and to the concrete. Hung the wire behind the washers. It took every fender washer in my small town to get 180' perimeter done.
Keep the weed whacker away from the finished job. No termite problem? Where are you, in my wife's home state of North Dakota?
Live in Alberta, Canada.....You mentioned to stay away from the finished job with the weed wacker. Must be because nailing to the foam makes for a soft backer? I was thinking of nailing some 1/2" treated plywood strips through the foam into the concrete then attach the mesh to the ply then stucco. This should make for a stiffer backing...... Jeff
I have seen some posts where they completely covered the foam with PT ply, though I don't know how well the ply well stay together if it is wet for an extended period of time. I am not sure, but IMHO I don't think that a cementitious coating is moisture-proof, only water repellent. Just checked a code book and they specify a plywood rated for below-ground use. I know nothing about wood foundation materials. Good luck, stay warm.
BTW, I nailed through the foam, not to it. The whacker would chop through the coating after repeated assaults.
Edited 8/29/2002 10:11:09 AM ET by OLDLOU