ECN Forum Forums General Topics of the Trade General Discussion Area Foundation stemwall penetration

Im about to start a Gymnasium that has a
800a. 480v 3phase service and it's going to have both exterior and interior stem walls that i have to go through. In the past i've done it with the PVC conduit coupling sticking through the form but i'm wondering if it would be better if i used a larger sleeve flush with the inside of the form. If that would be the case what would be the best way to install it and seal it. Could you use a snap tie to hold it in place? Any other ideas?

Thanks in advance for your replies
Z...

Get the concrete guys to tie it in there with their wire so they are sure you are not encroaching on the "cover" over the rebar. A ton of concrete dumping in there will probably break a tywrap. I got into this tying my smurf in the tie beam and doweled cells on my addition a couple weeks ago. They took good care of me.

Stem Wall? Not familiar with that term. It sounds like you are talking about a concrete poured wall right?

By stemwall i mean a foundation wall that sits on top of the footing. In this case the footing is poured first then the forms for the foundation are built on top of that. I guess a stemwall can also be a concrete wall that extends above the slab.

What i call a snaptie isn't a tywrap but a tie that the carpenters use to hold the form together. Its like a rod about the diameter of #9 wire.

I can't count on the concrete guys to do this for me but we'll be working together so we don't screw each other.

"Snap tie"
OK gotcha. We are really just starting to pour that type of wall here but I know what you mean now. The company that was big in it went under and couldn't sell their forms. Usually a stem wall here is block with doweled cells (#5 rebar) and poured solid across the top when they pour the floor.

If its short and fairly straight you could fill it with expanding foam and a layer of duct tape then chip the foam out later. Other options, if the sleeve is long or curved, fill it with styrofoam "popcorn" packing material, or broken up styrofoam chunks and duct tape the hell out of each end. If you can swing a thin plug of expanding foam on each end in front of the loose stryrofoam chunks then duct tape it that would be good too. I am assuming you want to keep wet concrete out of the thing. As far as fastening goes, lots of tie wire and two small short rebar pieces at each end, tied in to the concrete guy's rebar..

No matter how you seal your conduit (female to female) be sure to run one of his snap ties down the middle to pull the form tight against the pipe and make sure you don't lose it.
I am really getting to be a fan of the concrete guy;''s red tape for these things

Im not sure what "red tape" is. what does it do?

It is a red (so the inspector can see it) PVC kind of tape that they use to seal the seams in the vapor barrier plastic but it is just a good tape. It holds well without the gooey mess you get with duct tape or cheap electrical tape and it is 2". I whipped the ends of wire bundles I shoved through me smurf tube the other day and they slipped through real well.

I have not done what you are doing, but just wanted to add if you need to seal the sleeve before concrete is poured could you use a Plumbers Test Cap to seal the ends?

http://www.doityourself.com/icat/testcapsandplugs