A common practice with bonded PVC liners is to install one thickness to the sidewalls (typically 3/32 in.) and a thicker gauge (3/16 in.) on the bottom. This may be sold under the guise of providing greater puncture resistance but in the end this is only for the installer’s benefit not yours.
Bonded liners require a skilled technician to apply each sheet to the tank. The sheets are 3 ft. or 4 ft. wide and individually applied. The normal fashion is to install material in the bottom and then run sheets vertically down the depth of the tank. The deeper a tank the heavier these sheets become. Naturally a thinner gauge sheet is going to be easier to apply on the sidewalls than a thicker gauge sheet. This is why bonded applicators will try to sell a thinner gauge sidewall. It makes their work easier for them.
The reason this isn’t in the customer’s best interest is that the liner will only be in service as long as the thinner material holds up. The extra money paid for the thicker bottom doesn’t keep the liner in service any longer than if the entire liner was the thinner gauge. It’s wasted money! You would be better served to have the liner made from one similar thickness throughout.
With a drop in PVC liner, it is just as easy to build the liner from a thicker gauge material and the installation is usually around the same cost as with a thinner liner. Therefore, the money invested in the liner and installation can be used towards a thicker and longer lasting liner.
Granted, a thicker liner on the bottom of the tank does provide greater puncture resistance than thinner sidewalls. However, the sidewalls can be punctured by falling parts just as easily as the bottom. If work production is such that the bottom is subjected to greater abuse than a rigid shield set up would be a much smarter investment.
With a drop in PVC liner, Witt Lining Systems has your best interests at heart when fabricating one of our long lasting flexible tank liners.