kozmo Posted February 9, 2011 Report Share Posted February 9, 2011 We have a guinite pool with a standard plaster finish located on a slope. The shallow end is on the high side of the slope and is in-ground. The back right side of the 7ft deep end is on the down sloppe and sits mostly above-ground. The back wall of the deep end rises 18" above the waterline and is covered in natural stone that extends below the water line where it then meets plaster. The stone is in constant contact with the water. There is tile around the rest of the pool at the waterline, but not on this wall. Can water be seeping through the stone/mortar and then through the guinite? I don't know if guinite is waterproof, but I'm pretty sure the stone isn't water proof and not sure the builder did anything special to seal the mortar joints between the stone pieces. Quote Link to comment Share on other sites More sharing options...
txpoolguy Posted February 9, 2011 Report Share Posted February 9, 2011 All stone is porous, though to varying degrees. Marble, for instance is very dense & less porous, while many flagstones are less dense/more porous. If you were losing water thru the stone, you would most likely see it on the outside of the wall. Sometimes, the installer will use a sealer behind the stone to help reduce seepage, but it's another expensive step that isn't always necessary. Are you losing water faster than normal? Quote Link to comment Share on other sites More sharing options...
PoolGuyNJ Posted February 10, 2011 Report Share Posted February 10, 2011 Gunite is not water tight and can weep. The plaster finish is water tight, as is the tile. Tile at the waterline is used to prevent plaster from being exposed to the elements. The stone on the raised bond beam should have a sealant applied prior to plastering near the waterline to just above, at the very least. The mortar used to adhere the stone is not watertight. Eventually, the mortar will break down and the stone facing that is at or below the waterline will become unstuck. The gunite will survive far longer, decades longer than the mortar, in fact. When the time comes to do the rock facing, let it dry for a week or so, use a sealant like Thorough-Seal which will also act as a bonding agent and you will never have this issue again. Scott Quote Link to comment Share on other sites More sharing options...
kozmo Posted February 12, 2011 Author Report Share Posted February 12, 2011 Thanks for the response poolguys from TX and NJ. Responding to your questions; "Are you losing water faster than normal" This pool is 2.5 years old and loses water faster than a similar pool we owned for 8 years before building this one. The two differences are, a hot tub that spills into the pool when the pump is on and stone at the waterline instead of tile. The stone is Oklahoma Flag stone which is definitely porous. I'm sure some additional water loss is due to the water spilling over the hot tub. More surface are of water = faster evaporation. But I also think the stone has something to do with it. "When the time comes to do the rock facing, let it dry for a week or so, use a sealant like Thorough-Seal which will also act as a bonding agent and you will never have this issue again" Unfortunately the pool is 2.5 years old. I think I am going to lower the waterline below the stone and let it dry for a week and then apply a good sealer. Will definitely check out Thorough-Seal. Quote Link to comment Share on other sites More sharing options...
PoolGuyNJ Posted February 12, 2011 Report Share Posted February 12, 2011 Applying a topical is not likely to be a lasting solution and weepage through this section is unlikely to be very measurable. Thorough-Seal is applied to the gunite before the thin set for the tile. If the pool and the spa are off, both will evaporate at the same rate. There is only a slight increase when the spa is spilling over as there is more surface area of water exposed. This evaporation, for the most part is negligible. Negative edges and waterfalls running may increase this to a more measurable rate. How much water are you losing per day? Scott Quote Link to comment Share on other sites More sharing options...
kozmo Posted February 13, 2011 Author Report Share Posted February 13, 2011 Hi Scott, I am dealing with 2 somewhat separate, but possible related problems. 1. The pool over the last 2.5 years has lost water faster then our previous pool. We add water 1 - 2 times a week. Both pools are in Austin, TX. Only 2 differences that I can think of. This pool has a spa and it has the rock face extending into the water line. I've been trying to determine if these 2 differences would account for greater water loss. 2. Over the last 30 days the water loss has accelerated. I'm estimating we are losing 1/2 - 1 inch of water a day. There is a wet spot in the lowest point in the yard below the pool. I'm positive we have a leak somewhere and not sure if it's related to the pump running much more due to the very cold weather or if it's a leak from one of the fixtures (we have three lights). I am going to do a bucket test over the next few days with the pump off to see if I'm losing water from something in the pool itself. If the water level remains relatively stable then I would surmise it is a cracked pipe - which would be very bad as most of my pipes run under the decking Does this sound like a good game plan? Quote Link to comment Share on other sites More sharing options...
PoolGuyNJ Posted February 14, 2011 Report Share Posted February 14, 2011 How wide is the decking? The seep through the stone is NOT your leak. That much water is either a broken pipe or the seal between the gunite/plaster, skimmer, return or drain. A bucket test will tell you that you are losing water with the system running and if it's different with the system off. If you are losing water with the system on but not off, you need a pressure test. If you lose water with the system off, you need a diver, assuming it isn't at the skimmer mouth. Any chance you are losing it out the backwash port? Quote Link to comment Share on other sites More sharing options...
kozmo Posted February 23, 2011 Author Report Share Posted February 23, 2011 Hi PoolguyNJ, it is definitely not coming out the backwash port. No visible water anywhere near the pump equipment. Since my last post I let the pump sit idle for 48 hours and the water level in the pool did not change. I've been out of town so haven't had a chance to check on things since that point, but definitely looks like it's related to the pump running. There are two pipes on the back of the pool, underground, that could be the culprit. The other possibilities are all under the concrete decking so less likely, but if they have somehow ruptured then I have big problems! Does my analysis sound correct or are there other things I should be considering? Quote Link to comment Share on other sites More sharing options...
PoolGuyNJ Posted February 27, 2011 Report Share Posted February 27, 2011 Since the level didn't change with the equipment off, it's more likely to be a cracked return line. Time for a pressure test. The reason I say it's likely to be a return is you haven't said you were having difficulty pulling prime. Scott Quote Link to comment Share on other sites More sharing options...
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