I poured a 1 CY foundation for an outdoor fireplace yesterday afternoon.
Temps here are ranging from highs in the 50's to lows in the mid 20's.
After pouring, I covered it up in plastic and put around 6-8" of straw over
the top of it. This morning, the concrete is visibly wet with a bit of
standing water on it in places. I've always poured in the summer and have
seen the stuff cure pretty quickly. I suspect this is normal for these
temps but was looking for any expert opinions on this. I was planning to
start putting my CMU etc... down probably next week but at this rate, I'm
not sure I'll be able to. How long should I leave the plastic/straw in
place before working on it? Thanks much for any inputs.
Remember this: concrete curing is NOT an evaporative process - ie. the
concrete does not really need to "dry" in order to cure. In fact, it's
better for the end strength of the pour if it is kept moist during the
cure process. There is a chemical reaction that combines the water
with the portland cement in the concrete mix. The cold weather will
probably slow down this reaction, but the moisture will actually help
it in the long run and won't slow the cure down any.
If you want strong concrete, keep the plastic on
to retain moisture and keep the straw on to retain
heat and avoid freezing. How long? however much
you want, but most of the strength develops in a
few days. anything amount of time is better than
pulling forms off and letting it dry out the day
after you poor it like they do around here for
Same here. They pour one day and are building on it the next. Maybe they
are using high early strength concrete, but I doubt it.
I'm headed back to work tomorrow so really the first chance I would have to
do anything with it would be Monday. So a week would probably be ok for me
to set a couple of courses of block on it.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.