New wood systems cut building costs

'f HE COST of building a home f can be significantly reduced by the use of three new plywood and lumber construction systems, all re' fined for practical application in the past l0 years and all recognized by major building codes.

A home built recently in Maryland with the All-Weather Wood Foundation (AWWF), underfloor plenum and the APA Glued Plywood Floor System cost $335 less than an identical house built on a concrete slab with conventional ducted heat, according to a cost study conducted by the National Association of Home Builders' Re' search Foundation.

Cost estimates prepared by the foundation also show savings compared to slab for the plenum system, using either wood or concrete foundations, in the representative geographical areas of Chicago, Arizona, Florida, North Carolina and Fresno. Ca.

The two test homes were built side by side by a Washington, D.C. home builder. He used the same crew to construct both houses.

Besides costing less, the AWWF/ plenum home saved 16 manhours (2O per cent) of construction time.

For a similar success story in Montana, see The Merchant Magazine, p. 12, August.

The study was sponsored by the American Plywood Assn., American Wood Preservers Institute, Southern Forest Products Assn. and Western Wood Products Assn.

The three wood construction systems used in ihe Maryland cost study are good examples of energy+fficient, cost-effective modern building techniques using lumber and American Plywood Assn. APA grade, -trademarked plywood.

The underfloor plenum is a method of distributing hot or cold air to all parts of the house without using costly ductwork (see drawing ).

Air is discharged downward from a conventional counterflow furnace into a tightly sealed, insulated space under the floor, called a plenum. From there, it passes up into the house through floor registers or a perimeter slot in the floor and baseboard trim.

Heating (and cooling) also occurs through the radiant effect (or heat absorption) of the warm (cool) floor. Those who have lived in houses with an underfloor plenum say it's both comfortable and energy efficient.

Although the plenum can be used with an ordinary concrete or masonry foundation, its use with the All' Weather Wood Foundation enhances building cost and energy'saving benefits.

The AWWF is basically below'grade insulated stud walls constructed of lumber and APA grade-trademarked plywood that has been pressure treated with preservatives.

The treated wood system, which can be built as a crawl space or a full basement, has several advantages over concrete or masonry foundations. An AWWF generally costs less to build and finish, and it can be installed in all kinds of weather conditions in hours instead of days. Even when compared to a conventionally-insulated masonry wall, an insulated AWWF loses onlY about one-half to one'third as much heat through the wall.

Story at a Glance

By using the new combination of the All-Weather Wood Foundation, under floor plenum and glued plywood floor, builders are signif icantly reducing costs. .all three are recognized by major building codes.

The AWWF is rapidly being accepted by builders and homeowners across the nation. Today there are roughly 10,000 homes standing on full basement wood foundations, virtually all of them built in the last five years.

The third construction technique used in the Maryland test home - the APA Glued Floor System - is a proven cost cutter. A single layer of tongue-and-groove plywood underlay' ment is glued and nailed to joists with obvious savings as compared to a conventional two-layer floor. The glue permanently bonds plywood flooring to joists to produce a quiet, sturdY floor.

For more information on these or other energy-saving, cost-efficient plywood construction systems, write to the American Plywood Assn., ll19 A St., Tacoma, Wa. 98401.

Cost-saving details on the new Plen-Wood foundation/floor/heating' cooling system are presented in the new eight-page technical manual, avail' able from Western Wood Products Assn., Dept. SP-3, Yeon Bldg., Port' land, Or. 97204.