A trick for cold weather pours that saved a job last month

I used to just throw a tarp over a slab and hope for the best if the temp dropped. Last month on a garage floor pour in Spokane, the forecast went south right after we finished. My buddy told me to lay down a layer of plastic sheeting directly on the wet concrete before the insulated blankets. The plastic traps the bleed water and keeps the surface from drying out too fast in the cold, dry air. We did it and the finish stayed perfect, no dusting or craze cracks. What's your go-to move for a surprise cold snap?

3 comments

3 Comments

ryant5011d ago

That plastic trick can lock in too much moisture sometimes. I've seen it cause a weak top layer if the concrete isn't just right. I still trust a good layer of straw under the blankets for a slow, even cure.

aaron88011d ago

Yeah exactly, that's the whole problem with it. I mean, I tried the plastic sheet thing on a small slab last fall and it looked fine at first, but the surface was just sort of dusty and weak when we went to seal it. It totally locked in the moisture like you said, but it cured way too fast on top. Straw and blankets might be old school, but you get that even, slow dry and it's just way more reliable. Idk, maybe it's just me but I won't use plastic again after that.

cameron_hernandez6911d agoMost Upvoted

So you guys who had trouble with the plastic, how thick was the sheet you used? I heard the really thin stuff can cause more problems than it solves.