Waterstop location-inside face or outside? 1

[WWTEng]

What is the best location for waterstop in a basement wall, inside face or outside face? I like to show the waterstop along the face that has vertical re-bar so that they can tie to it if needed. But if you have re-bar along both faces, what would be the preferred location?

Thanks,

 

[strucguy]

I prefer showing it on the outside face.

 

[JedClampett]

Why not in between the the reinforcing?
Also, for a basement you'll probably not get this, but the way you have it shown requires that the top slab bars be lowered to get the wasterstop in. We put in a "starter wall" that's poured with the slab to raise the waterstop. Contractors hate it with a white hot passion, but it is a little better design.

 

[SlideRuleEra]

I prefer bentonite waterstop. The manufacturer recommends placement between the rebar layers. See the attached spec sheet for the details:
Bentonite Water Stop

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[BAretired]

Except for water retaining structures or unusually wet sites, I never use waterstops between wall and footing.

BA

 

[msquared48]

If this a non-yielding basement wall with the rebar at the inside face of the wall, I would place any water stop to the soil side of that.

If this is a yielding wall with the rebar near the soil face, then I would put any water stop inside of that, away from the soil face.

Mike McCann
MMC Engineering

 

[hokie66]

Agree with Jed that using a "kicker" is the best way, to get away from the footing bars, and also to provide a backing for the formwork. This assists in keeping the formwork sealed, avoiding honeycombing. Using a kicker, I like to specify back face waterstops.

 

[Gumpmaster]

Hate to tell you SlideRuleEra, but bentonite is no longer considered that great. It breaks down over time and can start to leak. The modern replacement is chloroprene rubber. It has much better longevity.

We center the waterstop where there are two mats of reinforcing. Tying it against the rebar risks short circuiting the waterstop. Order the waterstop with hog rings and have the contractor demonstrate that they can tie it properly without flopping over. A contractor experienced in using plastic waterstops can pull this of fairly easily.

 

[asixth]

I use a product called hydrotite which goes straight down the middle between the reo.

 

[SlideRuleEra]

Uh-oh... Thanks, Gumpmaster. I'll scratch that recommendation in the future. Good example of how quickly a person (me) can get out of date after retiring.

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[Splitrings]

Be careful to meet the cover requirements if you are using bentonite waterstops. They will break the bottom of the wall.

 

[miecz]

Agree with BA, unless this is a wet site, I wouldn't use a waterstop. If you must, thread507-254953 also has some good info.