Builders and homeowners alike have opportunities to build wood forms to hold concrete, and the procedure is easy, but removing the forms can be many times more difficult. As the concrete sets and hardens, it makes no distinction between where a builder wants the concrete and where it is unwelcome. The challenge involved with removing forms compounds the longer you let the concrete set, but there are ways to prevent concrete adhesion and make the forms easier to remove.
Dip a paintbrush or paint roller into varnish. Apply the varnish to the wood covering all of the faces that will encounter concrete. Let the varnish dry for two to three hours. Paint a second coat of varnish on the wood. Let the varnish dry for two to three hours before pouring concrete.
Fill a hand-pump sprayer with oil. Any type of oil will prevent concrete from sticking to wood. Spray the surfaces that will face the wet concrete with a heavy saturation of oil. Allow the oil to penetrate the wood for 15 to 20 minutes. Apply a second heavy spraying of oil just before pouring concrete.
Open a can of commercially available, specially formulated form-release agent. Dip a paintbrush into the form-release agent. Coat the inside surfaces that will encounter wet concrete thoroughly. Allow the form-release agent to remain on the surface of the wood forms.
Dip a rag into lard or shortening. Coat the wood surface that you are protecting from concrete with a thick layer of lard or shortening. Examine the wood to ensure a lard or shortening coating covers all surfaces prior to pouring concrete.
Place the wood in a large trough. Fill the trough with water to cover the wood. Soak the wood for eight to 12 hours. The excess water content in the wood will prevent the concrete from sticking to the wood.