Old timer told me to wet the substrate before pouring and I thought he was nuts

Been doing concrete for about 3 years now. This 60 year old guy named Frank at the supply yard said I'd save myself trouble if I gave the dirt a good spray before I poured. I figured he was just wasting time. Then last month I did a small patio slab without wetting it first. The ground sucked all the moisture out of the mix and I ended up with a cracked mess. Had to rip it out and redo it. Cost me an extra $200 in materials and a whole Saturday. Has anybody else had the ground steal your water like that?

3 comments

3 Comments

the_thea1mo ago

...and then last spring I made the mistake of pouring a walkway on a day that was like 85 degrees and bone dry. I didn't wet the base first either. The sun was cooking the top while the ground underneath was just pulling all the moisture down. I had to keep spraying water on the surface just to keep it workable. Set so fast I barely got a decent finish on it. Frank was right man, I should have just listened to the old guy.

ruby_henderson361mo agoMost Upvoted

Read somebody say dry ground is basically a sponge for your mix.

bennett.evan1mo ago

Ah man, @the_thea nailed it. That dry ground is like a vacuum for water. I had the same thing happen with a walkway last summer. Now I always wet the base the night before and give it another light spray right before the truck shows up. For deep sandy soil you gotta really soak it, like run a sprinkler for 20 minutes, or the mix just bleeds out and you're fighting it the whole time.