I replaced our 18X36 sport pool liner this spring. Installed it myself while the wife was at work. Purchased the liner online from Water Warehouse. (Not affiliated with Water Warehouse).

Foam sidewalls looked fine to me as did the concrete bottom but had some pool patch just in case. Didn't use it. Replaced the skimmer & return plates and all new gaskets.

Fits as good as the original, if not better.

Total cost, $1100 + water

Hope this helps, Tony