FREE or CHEAP Computer Software for Builders: A broad array of builder's software is described in the new 1987 edition of the NAHB Research Center's Software Catalog for Home Builders. Don't look for any hardhitting reviews, as all descriptions are provided by the software manufacturers. But at $12 (including postage and handling) the catalog is a smart investment for anybody getting ready to computerize. Order from NAHB Research Center, 400 Prince Georges Center Blvd., Upper Marlboro, MD 20772-8731. Proper Spacing and Nailing: Improper spacing and nailing are the two most common causes of call-backs and claims by customers, according to the American Plywood Association. To help you avoid those problems, APA has a new fact sheet describing its spacing and nailing recommendations for sheathing, subflooring, and siding. Contact APA at P.O. Box 11700, Tacoma, WA
