Why are our concrete forms not lasting as long as they used to?

We use 1 and 1/8 inch overlaid plywood forms to construct residential basements and stem walls. For some reason we seem to be getting fewer pours on our forms. Is the reduced life of our forms related to the quality of the plywood, or is it due to the use of an ineffective form release agent? 

Although the reduced form life you are experiencing could be the result of many factors, the most likely cause of your problem is increased alkalinity of the concrete. The addition of certain pozzolans to concrete, such as Class C fly ash or blast furnace slag, can increase the pH of fresh concrete, causing increased damage to overlaid plywood forms. To maximize your overlaid plywood form life, restrict the use of highly alkaline pozzolans in your concrete mix design, and use Nox-Crete form release agents on your forms.

Nox-Crete’s chemically reactive form release agents react with calcium hydroxide (lime) in fresh concrete to form metallic waterproof soaps which, over time and through use, waterproof plywood form surfaces and effectively restrict further penetration of destructive alkaline bleed water.