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Posted By: zero76 Foundation stemwall penetration - 06/01/08 03:31 PM
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...












Posted By: gfretwell Re: Foundation stemwall penetration - 06/01/08 04:12 PM
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.
Posted By: JValdes Re: Foundation stemwall penetration - 06/01/08 04:17 PM
Stem Wall? Not familiar with that term. It sounds like you are talking about a concrete poured wall right?
Posted By: zero76 Re: Foundation stemwall penetration - 06/01/08 04:57 PM
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.
Posted By: gfretwell Re: Foundation stemwall penetration - 06/01/08 06:40 PM
"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.
Posted By: trollog Re: Foundation stemwall penetration - 06/01/08 07:34 PM
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..
Posted By: gfretwell Re: Foundation stemwall penetration - 06/02/08 12:14 AM
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
Posted By: zero76 Re: Foundation stemwall penetration - 06/02/08 12:21 AM
Im not sure what "red tape" is. what does it do?
Posted By: gfretwell Re: Foundation stemwall penetration - 06/02/08 04:19 AM
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.
Posted By: forqnc Re: Foundation stemwall penetration - 06/02/08 03:01 PM
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
Posted By: gfretwell Re: Foundation stemwall penetration - 06/02/08 03:28 PM
If the ends of your conduit is the same as the thickness of the wall, square and you pull the form up tight to it you shouldn't get any concrete in it, maybe a little cream.

You could stuff it with balled up newspaper to keep it from getting filled if you did have a slip.
Posted By: EV607797 Re: Foundation stemwall penetration - 06/02/08 03:42 PM
I was going to suggest the plumber's test caps too. They are designed to be glued in place for a nice seal, then they are just popped out with a blow of a hammer. All that is left is a thin ring around the edge of the pipe that won't interfere at all.
Posted By: zero76 Re: Foundation stemwall penetration - 06/04/08 02:07 AM
The plumbers test caps sound like a good idea but i'm going to use duct tape [one size fits all] cause thats what i have handy. Whether it's foam, styro peanuts, or newspaper, i think it's a good idea to fill the sleeve just in case.

Thanks for all the good input,
zero
Posted By: NJwirenut Re: Foundation stemwall penetration - 06/04/08 02:23 AM
If you use the test caps, you wouldn't be able to run the snap tie through the pipe, which is important to make sure your pipe stays where you want it.
Posted By: Obsaleet Re: Foundation stemwall penetration - 06/09/08 02:42 AM
use a rubber fernco blank, and just poke the snap tie or tie wire through the rubber and you are done. Or duct tape LOL

ob
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