Let’s discuss Vinyl Liner Pool Bottoms, as there are several ways to install a bottom under a vinyl-liner in a new pool installation.
The oldest way, and the worst way, was to trowel some sand on the dirt, wet it , and try to make it smooth before laying a vinyl liner over it. That way is horrible, because you get foot-prints in the bottom of the liner, which look terrible after a few uses of the pool by the swimmers.
Another way that many, cheap vinyl pool builder/installers have placed on the bottom, under the liner, is to mix sand with cement in a mixer, and then trowel it on, over the dirt bottom, and then lay the vinyl-liner over it. This eliminates the foot-print problem that one has with just plain sand. Unfortunately this much cheaper method, of sand/cement, does not hold up very well after a few years, and can actually shorten the life of the liner because it is an abrasive substrate. When one goes to change the liner, for a new one, this cheap type of floor, sticks to the bottom of the old liner and causes deep pockets, where the sand/cement has lifted off. This then requires, a lot of work to fix the bad spots with new material before one can lay a new liner over the old bottom.
For a smooth, permanent, and mostly trouble-free vinyl pool bottom, the proper, but more expensive way, to install a bottom, is to use ONLY VERMICULITE & PORTLAND CEMENT, (NO SAND AT ALL IN THE MIX!) that is mixed in a mortar mixer, and then troweled-on like concrete decking!
Troweled to a smooth surface, this mix provides a non-abrasive substrate. It supports and cushions the liner much better than sand/cement bases. It doesn’t mold, decay or deteriorate from moisture contact, and will help insulate the pool. And there are no footprints or rot, in a Vermiculite & Portland Cement mixture. Questions call Rich at: 609-313-0300…..www.paradisepoolandspa.com