0ld Silo Beconditioned lTith Plvwooil

they would have been crushed by a thorough job of hoop fiohfeninq

There were, however, several factors indicating that the old cylinder might be reconditioned economically. The base was unusually sound, and the structure was especially straight for its age as it had been protected from wind by other nearby buildings.

Accordingly, it was determined to reline the old building rvith 5/16-inch Exterior plywood to prolong its usefulness.

Hoops were tightened as much as the condition of staves and threads would permit. The plywood panels were coated on one side, that which would be against the inside of the old silo, with emulsified asphalt and the coating permitted to dry before panels were installed. Then, the plywood was applied vertically being nailed with 6d nails approximately 6 inches on centers at panel edges and 12 inches on centers elsewhere. Panels were fastened to every stave in the old silo.

Plywood edges were merely .butted both at the vertical and horizontal joints.

Finally, half of the new inner surface of the silo was given a coat of asphalt paint from the base to the top. The other half of the plywood was left unprotected for comparative purposes.

A 30-year-old silo, previously considered beyond ordinary repair by replacement of individual staves, again is proving its usefulness after being relined with Exterior type Douglas fir plywoo<i.

Located at Western Washington Experiment Station at Puyallup, the silo now is filled with grass ensilage for the second time after the rejuvenation project. The lining is expected to extend the life of the silo by l0 or 15 years.

According to John Alswager, dai'ry husbandryman at the station, use of the reconditioned silo has been entirely successful to date with virtually no spoilage of silage during the first storage period.

Tight construction, which prevents air infiltration or leakage of juices is, of course, one of the features of allplywood silos. Lining of the deteriorated structure with the panels is believed to have accomplished to a high degree the same conditions.

Lining of the silo was undertaken after it was determined in 1944 that the general poor condition of the then , existing building did not warrant further repair work by replacing a few staves at a time. Threads of some of the steel hoops had rusted so that proper tightening was impossible. Fnrther, some of the staves \\,'ere so rotted that

During the relining it was learned that the silo, although it appeared straight and plumb, was smaller in diameter at the mid-section than at the top or base. fnasmu'ch as the plywood already had been cut for butt joints throughout, there remained V-shaped spaces between panels at the top and bottom when installed. These, however, constituted no serious problem and were merely given a heavy coat of asphalt.

Experience during the project indicates that for silos that are not true cylinders one or two other lining application procedures might be followed. Each plywood panel may be plumbed and the edge trimmed to fit against the preceding panel, at the same time keeping the top of the course level. Or, it is feasible to over-lap each panel approximately 2 inches to take up irregularities, keeping the top of the course level. Overlapping, the panels adds to the reinforcement.

Nonetheless, the appli,cation technique used for the Puyallup silo probably remains the simplest to follow and results to date indicate the project entirely successful.

Pine Plywood Plqnt At Toyon, Cclif.

Calaveras Forest Products Corp. has been manufacturing California pine plywood at its plant at Toyon, Calif. since January 1.

This concern is a subsidiary of American Box Corporation, and the sales are handled by Tarter, Webster & Johnson, Inc., San Francisco, Los Angeles, and Stockton.