Q&A for How to Pour a Concrete Foundation

Yes, it would need to be replaced. If there is no horizontal rebar in pour and only upright, then the concrete is not reinforced structurally and may fail load bearing.

In most places, you'll need to submit a proposal to your city before you start. Once that's approved, you have to dig down to solid ground, then attach the rebar to the original foundation that you're attaching to.

Yes, you need a footing under all foundation walls, including garages.

Yes. You should make the tops of your foundation forms level so that when you screed off the concrete, you are left with a level surface.

It can vary by concrete type and ambient temperature. It will support your weight in a few hours, and is essentially fully cured at about 4 weeks.

You should poor the whole thing at once. The part about pinning the foundation is if you're pouring next to an old foundation.

A V will make absolutely no difference, especially if the footings are underground.

Are you talking about a mono-pour? This is a more complicated pour, but is better than the two-pour method because you do not have the weak cold joint between the footing and the stem wall.

If you’re in a very dry climate, you probably have no problem. However, if you’re anywhere else, you have a significant problem. If there’s ground water up to the slab, your concrete’s pores will fill with water. If it freezes where you are, the water in the concrete will freeze. Even if there is groundwater at the concrete or block footer, the water will wick up the footer into the slab. You are taking a huge risk by building on top of your foundation without the sheeting.

All the water has to be out of the trench, and you should be looking at dry #6 rock or what the building code mandates. I like #6 rock with 2 layers of landscape fabric on top. This really is more difficult than most “do it yourself projects”, and getting it wrong it could be very expensive. There’s a lot to think about, from getting the water out now, to having the water drain away from the foundation after the trenches are filled in. And of course, all the foundation work in the middle.