Pouring concrete near my machines

[Aaron_W]

I have a basement shop that has a section of floor about 10x12 done in concrete, a larger area is plywood and then rest is dirt. For whatever reason the concrete pad starts 6-8 feet from the door. I'd like to finish this section off (about 6x12) so that I have concrete all the way to the door.

Something that occurred to me is the potential humidity increase of the curing concrete? I am in a fairly dry climate, the basement is heated and I keep a couple of fans going 24/7 so rust has not been a serious issue. I keep things oiled just in case, and of course can take extra precautions when I pour the concrete, but now I'm kind of curious how long it might create enough humidity to be an issue if an issue at all.

In heavy rain storms I do get some water in the basement which has not been a problem, so this may concern over nothing. Of course I will move what can be moved, and will give any bare metal a liberal oiling, I'd just hate to have everything flash rust a month later when I've gone back to my old ways.

Anyone with experience pouring concrete in their occupied shop?

 

[rabler]

Sounds like you won't have a problem with the heat and fans, as proven by the water you get in the basement during a storm. But as a little extra insurance if you're worried, once the concrete is set up a few hours, you can cover it with plastic film or even the cheap painters plastic drop rolls. That will keep the moisture in the concrete, which improves the concrete curing, and will reduce any humidity issues.

 

[benmychree]

I think not a problem in our climate Aaron.

 

[DAT510]

As long as your in there, you might consider adding a french drain and a sump, when you pour the new slab area. (Given you've experienced water down there after heavy rains.) Cheap insurance.

Not my shop, but when I helped a friend pour a slab on the side of his garage that was gravel, we put up a wall of plastic sheeting to isolate his machines from any concrete splatter etc. If your worried about moisture blocking it off with plastic sheeting would reduce the moisture in your machine area.

 

[Dan Krager]

My biggest concern with pouring and curing concrete in an enclosed area is the presence of "base" fumes. Concrete is chemically active until it cures and the fumes carried off with the moisture are chemically base (opposite of acid). It's not strong and is unlikely to penetrate the fresh oil on surfaces. A few squirts of WD40 into drawers of fixtures and bits might not hurt anything....
DanK

 

[JRaut]

you can cover it with plastic film or even the cheap painters plastic drop rolls. That will keep the moisture in the concrete, which improves the concrete curing, and will reduce any humidity issues.

+1 for this.

Tossing some plastic down will help reduce fresh cracking while the concrete cures, with the added benefit of keeping the moisture out of the air.

Adding some wet burlap under the plastic will help the concrete even more.

Keep the plastic on there for a week or so. Spraying a little water on the fresh concrete every day will also help to reduce cracking too.

 

[Janderso]

Aaron, how are you going to do the job?
Professionally? Mixer and buckets?
I poured concrete once. My brother helped me. It was my first home, I thought the carport should be concrete.
Let’s just say I didn’t measure properly and so we ran out about 3/4 into the job.
The driver said, just lower the guides and pull your float back over the work.
Being 21 years old and very impressionable, I agreed to try it as he drove off with his empty truck.
Thinking back, I should have stopped at a clean line and ordered more on another day.
The end project was the worse concrete job in the history of the state.
I retired from concrete work after that

 

[Aaron_W]

Thank you, I didn't think it would be a big issue, but then I ran across a comment where it mentioned poorly cured concrete could be the source of rust issues drawing moisture into the shop.

Most of the machines closest to the spot can be wheeled further back into the shop, or moved outside into a covered area but the 11" lathe is pretty much set where it is about 6" from the edge of the existing concrete. I had planned on giving everything a good coating with my ATF, lanolin and mineral spirits cocktail, but some plastic drop cloths are a good idea, and I didn't know about covering the concrete to help hold the moisture in.

As long as your in there, you might consider adding a french drain and a sump, when you pour the new slab area. (Given you've experienced water down there after heavy rains.) Cheap insurance.

Not my shop, but when I helped a friend pour a slab on the side of his garage that was gravel, we put up a wall of plastic sheeting to isolate his machines from any concrete splatter etc. If your worried about moisture blocking it off with plastic sheeting would reduce the moisture in your machine area.

The water issue is simply a case of an old house settling. There is a concrete walkway just outside that over the years or from bad design creates a low spot in front of the door and allows water to pool against the door instead of draining off to the yard. When there is a heavy rain the puddle gets big enough to drain into the doorway The proper fix is fairly simple but involves a sledge hammer and redoing the walkway so it slopes the right way.

Aaron, how are you going to do the job?
Professionally? Mixer and buckets?
I poured concrete once. My brother helped me. It was my first home, I thought the carport should be concrete.
Let’s just say I didn’t measure properly and so we ran out about 3/4 into the job.
The driver said, just lower the guides and pull your float back over the work.
Being 21 years old and very impressionable, I agreed to try it as he drove off with his empty truck.
Thinking back, I should have stopped at a clean line and ordered more on another day.
The end project was the worse concrete job in the history of the state.
I retired from concrete work after that

Probably a wheel barrow and buckets. I'm not great at concrete work but I've helped pour a few small slabs over the years. The existing slab is pretty crummy with a really rough surface so I think I can do at least as well. I've got some inexpensive but durable commercial vinyl flooring on top of the other section, and have enough left over to finish the new area so solid and mostly flat is all I need.

 

[Bi11Hudson]

It was general practice (good practice) to cover a concrete slab after casting with burlap but I don't know enough about concrete to say how long it should stay covered. I do know that in the old days, the burlap was moistened on a regular basis implying that plastic sheet might not be so good an idea. I remember from childhood that the slab was dressed before covering, and the contractor would pay several visits.

The whole concept is 60 plus years back, so I don't remember the details so clearly. I did have a slab cast some 20-30 years ago. It was out in the open and the "contractor" was actually a "jack legged" wannabe. He didn't cover it at all, the last yard (of 17) was very weak, and he just walked away when the pour was not dressed properly. I didn't pay him fully either, so we're sorta even. But with footings cast (monolithic slab) as part of the slab, there was no digging it out and doing it correctly. In making the best of a bad situation, my intended concrete block garage is now a wood framed barn. ces't la vie

The point of the barn is that with no covering the slab is very 'chalky'. It is solid, I can't break it with a railroad hammer. And the Hilti gun will only penetrate a half inch or so. But for the first 10 years or so, it would dust to the point that my shoes got covered. I kept the machines in the wood structure (old house) to avoid the dust. The 'barn' is just a storage building now. I suppose that I could add another inch or two with a proper finish and raise a block building with a good floor. But I'm in the chair now and don't get out as much so it's a moot issue.

.

 

[Weldingrod1]

Concrete needs to stay wet for the first two weeks so the hydration/cementing process can reach its maximum strength. Covering with plastic -really- slows down evaporation. Wet burlap was how they did it before plastic sheeting ;-)

Sent from my SM-G715A using Tapatalk