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| <p><strong>NATURAL RESOURCES CONSERVATION SERVICE CONSTRUCTION SPECIFICATION</strong></p> |
| <p><strong>TIMBER FABRICATION AND INSTALLATION</strong></p> |
| <p>1. SCOPE</p> |
| <p>The work shall consist of the construction of timber structures and timber portions of composite structures.</p> |
| <p>2. MATERIALS</p> |
| <p>Structural timber and lumber shall conform to the requirements shown on the drawings. Unless otherwise specified on the drawings, timber and lumber shall be treated with chromated copper arsenate and shall have a minimum net retention of 0.6 pounds per cubic foot for placement in ground contact and 0.4 pounds per cubic foot for above ground use.</p> |
| <p>Hardware, except cast iron and stainless steel, shall be galvanized or cadmium plated. Unless otherwise specified, structural steel shapes, plates and rods shall not be galvanized. Driftbolts, dowels and screws shall be either wrought iron or medium steel. Nuts, washers and bolts on a single structure shall all be of the same material and have the same coatings.</p> |
| <p>3. WORKMANSHIP</p> |
| <p>All framing shall be true and exact. Timber and lumber shall be accurately cut and assembled to a close fit and shall have even bearing over the entire contact surfaces. No open or shimmed joints will be accepted. Nails and spikes shall be driven with just sufficient force to set the heads flush with the surface of the wood. Deep hammer marks in wood surfaces shall be considered evidence of poor workmanship and sufficient cause for rejection of the work.</p> |
| <p>Holes for round driftpins and dowels shall be bored with a bit 1/16 inch smaller in diameter than that of the driftpin or dowel to be used. The diameter of holes for square driftpins or dowels shall be equal to one side of the driftpin or dowel. Holes for machine bolts and rods shall be bored with a bit of the same diameter as that of the bolt. Holes for lag screws shall be bored with a bit not larger than the body of the screw at the base of the thread.</p> |
| <p>Washers shall be used in contact with all bolt heads and nuts that would otherwise be in contact with wood. All nuts shall be checked or burred to effectively prevent nuts from removal, with a pointed tool after being finally tightened.</p> |
| <p>Surfacing, cutting and boring of timber and lumber shall be kept to the practical minimum where cutting of treated timber and lumber is required. All cuts and abrasions shall be carefully trimmed and coated with not less than three brush coats of a commercially available wood preservative or sealer.</p> |
| <p>All recesses and holes cut or bored in treated timber and lumber shall be swabbed with not less than three coats of a commercially available wood preservative or sealer. After field treatment any unfilled holes shall be plugged with tightly fitting wooden plugs treated with a commercially available wood preservative or sealer.</p> |
| <p>4. HANDLING AND STORING MATERIALS</p> |
| <p>All timber and lumber stored at the site of the work shall be neatly stacked on supports above the ground surface and protected from the weather by suitable covering. Timber and lumber shall be close-stacked. The ground underneath and in the vicinity of all stacks shall be cleared of weeds and rubbish. The use of cant hooks, peavies or other pointed tools, except end hooks, will not be permitted in the handling of structural timber or lumber. Timber and lumber shall be handled with rope slings or other methods that will prevent the breaking or bruising of outer fibers, or penetration of the surface in any manner.</p> |
| <p>5. ADDITIONAL ITEMS WHICH APPLY TO THIS JOB</p> |
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