Standard Details of Construction and Specifications for Sheet-Copper Work

Ten Rules for Applying Copper Flashings

RULE 1. Use 16-ounce soft (Roofing Temper) copper only.

               (a) Do not use hard (Cornice Temper) copper except for cornice work.

               (b) Do not use lighter than 16-ounce copper.

RULE 2. Prepare the laying surface carefully and see that it is smooth and even.

               (a) All flashings, gutter-linings, etc., should be laid on rosin-sized paper or asbestos felt.

               (b) Sheathing boards should be ship-lap, tongued-and-grooved, or splined.

               (c) All nail heads should be set.

RULE 3. Avoid sharp bends in copper sheets.

               (a) Do not crease the sheets or bend them more than 90°.

               (b) Bend the sheets as little as possible before laying.

RULE 4. Allow for the movement of copper at intersections of roof planes by large loose-locked joints.

               (a) Never carry a copper sheet over an angle more than 3 or 4 inches.

               (b) Break the sheet and lock it to the adjoining one by means of a loose- or double-locked joint. This allows room for expansion and contraction.

RULE 5. Never nail copper sheets. Use cleats.

               (a) By "sheet" is meant any piece over 12 inches wide.

               (b) Use two-nail cleats 1½ inches wide and place them not more than 12 inches apart.

RULE 6. Use copper nails only - never iron or steel - for fastening strips and cleats.

               (a) Flat-head, wire nails are the best.

               (b) Strip copper should be nailed along one edge only.

               (c) Nails should be spaced 4 inches maximum.

RULE 7. Make full size joints and seams.

               (a) Standing Seams at least 1-inch finished.

               (b) Flat Seams (locked) at least ½-inch finished.

               (c) Lapped Seams at least 1-inch finished.

               (d) Double or copper-locked Seams at least ½-inch finished.

RULE 8. Tin carefully and thoroughly.

               (a) Use heavy tinning-coppers.

               (b) Use enough tin to cover all the surface.

RULE 9. Use rosin as a flux rather than acid.

               (a) If acid is used see that it is properly and thoroughly killed.

RULE 10. Plenty of solder, well-flowed over, makes strong seams.

               (a) Use the best half-and-half solder and lots of it.

               (b) Heat the seam thoroughly.

               (c) Heavy, hot coppers are best for this.

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