11

I strive to not waste materials wherever possible, and "use once then discard" methods are particularily irksome. So with this mind, what suggestions do you have for enabling re-use of lumber used for concrete forms?

10

If you use it for a form again no problem . . . otherwise, the remnants of the concrete on the wood will damage your power tools.

9

Going on the advice of a friend who used to teach carpentry, we painted the boards with a light coat of oil before building the forms. When we knocked the forms apart there was little concrete stuck on, perhaps 10% coverage. I let the boards sit and dry out completey then wacked them with a hammer, taking care of another %5 or so. After that a belt sander with coarse grit paper removed the remainder of the concrete and oil stains.

The final result is boards that while not good as new are suitable for most applications (might not be paintable) and safe for power tools. We're using them for our deck joists.

2

Anybody that's ever watched a concrete skyscraper go up in New York knows that you can reuse lumber forms again and again. Typically they'll have two complete sets of forms, one which ends up being used for the concrete structure on odd-numbered floors, and another which is used for the even-numbered floors. While the concrete is setting on, say, floor 17, they are removing the forms from floor 16 and hoisting them up to use floor 18.

1

I would save it to re-use as a form, or for bracing, or other one-off uses.

1

Depending on how you set it up you can build the frame on the inside of the plywood forms so that the bracing ends up being flush with the concrete. This allows them to be left in place and used in place of furring strips to attach insulation, siding, etc... or you can set it up so that they aren't flush, so that you may use the space for additional insulation. These methods have the added benefit of not requiring you to drill holes or use concrete nails etc... that weaken the structure. After you remove the plywood from the exterior, you can remove the majority of the concrete with a large spade and reuse them for floor or roof decking.

-2

Re-use for forms. Lumber is cheap anyways, so go get yourself a new piece if you want to use the same type of wood again.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.