Repairing a Spa Spill-over
Glass block is a dramatic and decorative way to separate pool and spa but has one major weakness. It's made of glass.
A teen swimmer dove off the marble plate on top of this spill-over which loosened the plate and snapped a corner of one of the glass blocks.
Pool water seeped into hollow sections of the block, stagnated and soon turned an unappetizing green.
There are three ways we correct this problem on the Pool School CD: Tile over both the pool-side and spa-side glass walls and reset the marble plate, Remove the glass block and form and pour a concrete wall to make a completely new and different spill-over or Replace the old glass block with new glass block to regain the original look.
In this case, the homeowner liked the look of glass block and wished to regain it.
The repair starts by completely draining the spa into the pool. Prevent water intrusion from the pool by closing the spa main drain, return and turbo valves.
(top photo) Grout between the blocks is cut with an angle grinder fitted with a 4.5" dismond blade. Wear glasses and a dust mask, this part of the job gets dusty but the more grout you can remove makes the block that much easier to extract.
(photo left) Whack the block with a rubber hammer. You're not trying to break the glass, you're simply trying to knock the block loose. In this case, it took a full five minutes to remove the first block but the others came progressively faster. Try not to crack the glass but collect any shards before they can slip into the pool. I highly recommend a clear, full face shield, twin- cartridge respirator and a long sleeved shirt for this job.
Glass block seems to be waning in popularity and you may find that the exact size of your glass block is no longer available. In this particular case, only a slightly smaller block could be found but the difference was easily made up with cement where the block meets the spa wall.
A special glass block cement is offered but standard tile thin-set is all that was needed for this repair. You can use a margin trowel, kitchen spoon or paint scraper to apply the cement. Be generous and fill all hollow areas on each side, these grout lines also have to be waterproof. Have a water bucket, a light acid mixture (1 muriatic acid: 4 water) in a separate bucket and a sponge handy.
The marble plate is secured with the same thin-set mixture and set with a pocket level to make sure it sheets the spill-over flow evenly. Use the sponge and acid mix to remove any cement haze from the plate and then rinse the sponge with plain water and remove any acid from the marble as it will stain. Give the repair a day to cure before you refill the spa.
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