Q.: We've had a recent inquiry about how to make nailable concrete. We recall that sawdust concrete was promoted for this purpose at one time. Is there anything new on the subject?

A.: Very lightweight concretes accept ordinary nails readily. Normal-weight concretes can be nailed with powder actuated tools.

At least 40 years ago sawdust concrete was promoted for its nailability (see "Waste Materials in Concrete," September 1971 issue, page 372). Perlite concrete, vermiculite concrete, cellular concrete and concrete made with foamed polystyrene beads, which in this country are usually made in the density class of about 20 to 50 pounds per cubic foot, will all accept nails. The same concretes made at higher densities will undoubtedly do so also. We know of no standard method, however, of testing nailability of concrete, nor any specifications for nailability.

Normal-weight concrete can routinely be nailed with powder actuated tools (see "The ABC's of Powder Actuated Tool Fastening," March 1976 issue, page 113). The method can apparently be used successfully with concrete in the compressive strength range of about 1400 to 5000 psi.