CONCRETE ROOF SLABS

   When copper is used over concrete the surface should be made smooth by a wash of neat cement. Elastic cement is sometimes used for this purpose.

   Cinder concrete should not be used in contact with copper. Where copper is used in this type of construction the concrete should be painted with a heavy coating of asphalt paint before the copper is applied.

   Wood battens or expansion inserts must be set in the concrete for fastening the cleats.

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RULE 3. Avoid sharp bends in copper sheets.

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

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

RULE 4.

Allow for movement at intersections of roof planes by 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.

EXPANSION AND CONTRACTION

   The temperature at the time the work is done must be taken into consideration by the contractor in allowing for expansion and contraction. A roof laid in July needs little room for expansion. It does, however, require ample provision for the contraction which comes with cold weather. The reverse is, of course, true when a roof is laid in cold weather, and under these circumstances the contractor must be careful to provide ample room for movement.

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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.

(a) Flat-head, wire “slating," or “shingle,” nails are preferable.

CLEATS

   Always secure the copper sheet by copper cleats, the cleats only being nailed to the roofing boards, the battens or wood ribs. Never use nails of iron or steel to fasten copper at any place or under any circumstances. Galvanic action will quickly destroy the ferrous metal.

COPPER AND OTHER METALS

   If possible, never use copper in contact with another metal, but if the plan of construction requires the use of iron or steel, by all means see that the iron or steel device is heavily tinned or that sheet lead is inserted between the copper and the other metal. The use of brass devices is recommended, especially for gutter and eaves trough hangers.

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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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