Need info on waterfall build...

[reef n ale]

I haven't talked to my PB about this yet because I wanted to see what you guys think.

I'm having a small waterfall done and my PB is using a shelf to build it on. The stone that sits in the shelf will be sitting in about 3-4" of water.

I came home the other day to find the gunite shelf coated with what I think is tar. I'm at the stage of just gunite-no tiles or coping yet.

Does this sound right or normal???!!! Tar???!!!

I'm at at loss as to how this should go and how it fits into the pool build.

Please help!!!

Rob

 

[stever]

The gunnite is not considered waterproof -- it will let some moisture through. The plaster makes the pool water-tight. if the rocks will be placed on the gunnite, there would be no plaster in this area. My guess is that the 'tar' is to seal the gunnite from water getting through (in or out). Our PB said they seal the shotcrete behind stone veneer on a raised bond beam to keep water from hitting it from behind and causing efflorescence.

Steve

 

[TresW]

The shelf is going to be below the waterline? Is there some kind of a step beyond the stone? The coating is probably as Steve said, to waterproof the surface of the gunite. Our PB used a coating over the gunite shelf under our waterfall and grotto as well, but the shelf on ours was above the waterline. If yours is below the waterline, water will seep through under the stone. Hopefully they've got a shelf behind the stone to contain the water.

 

[reef n ale]

Thanks for the replies, guys!

Here is a closer pic of the shelf before the tar coating. I'm estimating the stone will be sitting in about 3" of water.

Does this all make sense? :?

It's raining here today, so I'll try to get a pic with the coating tomorrow.

 

[TresW]

Good, they do have a containment curb behind the shelf. That should work fine. Did they turn the waterproofing material up the curb at the back?

 

[reef n ale]

Yes, the bottom of the shelf and the curb up the back is all covered. I guess I'm trying to find out about the choice of material used.

Will tar sitting in water last? Will it do anything funky to the water?

Rob

 

[TresW]

I doubt it's tar, it's probably bituminous waterproofing. It's used all the time in roofing, but I don't know if that's a widely accepted product for use in pools. If you're concerned about it ask your PB what they used and discuss it with them. If still concerned, find out the exact product and look it up online.