Waterstops

[NS4U]

I have a below grade covered tank. The water table is a few feet below the bottom of the slab so leakage into the slab is not a huge concern. The only real concern is during a floor or heavy rain.

At a minimum, I am going to spec ribbed waterstops all around the perimeter between the slab and the walls.

I have done some reading, but I can't find anything that talks about what size I should spec the waterstops. And there seems to be mixed reviews about whether waterstops are need are construction joints of the tank.

Does anyone have any recommendations for waterstop sizing and whether they are needed at the wall construction joints? Are they needed at the mat slab construction joints?

Thanks

 

[JedClampett]

Use 6 inch wide by 3/8 inch thick, non tapered waterstop for all construction joints. Greenstreak Model #679(

http://www.greenstreak.com/Div3/Waterstops/pvc_prods.asp?MenuID=1)should

do the trick. Centerbulbs are not necessary for non moving joints.

 

[UcfSE]

Have you considered using bentonite, such as Cetco Waterstop-RX?

 

[jike]

I use 6" PVC for non-movement joints and 9" for expansion joints (with center bulbs). I also put base seals in the mat.

 

[cvg]

wider and thicker waterstops are somewhat easier to construct just because they are a little beefier. If you want to make your tank as leak resistant as possible, use the waterstops. It is relatively cheap insurance. I have used the Greenstreak #732 6" wide pvc with center bulb which can tolerate movement and it has worked well.

 

[haynewp]

I know you say waterstop, but is this tank actually for fuel or water?

 

[NS4U]

For all intents and purposes the tank I am designing is a hollow structure in the ground. Being "water tight" is not a requirement but I think it is good practice for the "just in case" scenario.

 

[civilperson]

Concrete is not water tight, merely water resistant. Add a FRP liner for true water impermeability.