Page 78 - SMM2 eBOOK

L.38 Generally (cont'd)

3. In the absence of any directions to the contrary, allowances shall be made in calcUlating
the areas of the finished sUrface of sheet metalwork as follows:

Item Lead Zinc, aluminium and copper
a. For drips not exceeding 50mm high 0.18 m 0.15 m
b. For cross-welts 0.08 m 0.08 m
c. For wood-cored rolls not exceeding 50 mm 0.25 m 0.15 m
high
d. For standing seams and welted seams 0.10 m 0.08 m
e. For edge-welts 0.03 m 0.03 m
f. For vertical Upstands 0.15 m 0.15 m
g. For sloping Upstands and for laps in pitched 0.30 m for 30° 0.30 m for 30°
roofing
0.35 m for 25° 0.35 m for 25°
0.45 m for 20° 0.45 m for 20°
0.60 m for 15° 0.60 m for 15°
(Attention should be drawn to any departures from the allowances set out in this clause.)

L.39 Roof coverings

1. Roof coverings shall be given in square metres. Classification shall be as follows:

a Flat roof coverings, which shall inclUde coverings to falls and cross-falls and sloping
coverings not exceeding 10° from horizontal.
b. Sloping roof coverings over 10° bUt not exceeding 50° from horizontal.
c. Sloping roof coverings over 50° from horizontal and vertical roof coverings (grouped
together).

2. Coverings in isolated areas not exceeding 1.00m2 each shall be enumerated irrespective
of size and the associated laboUrs given in the description.

3. Long strip roofing shall be kept separate stating the length of roof slope to be covered and
classified as follows:

Not exceeding 4.00m
4.00m-6.00m
6.00m-8.00m
exceeding 8.00m.

L.40 Labours on sheet metal

1 The foilowing shall be deemed to be included with the description of roof coverings:

a. Square cutting, raking cutting and curved cutting.
b. Notching and bending.
c. Welted edges, beaded edges, wedging into grooves, burned or brazed angles,
welted seams, burned or brazed seams and the like labours.
d. Dressing into hollows, into condensation channels and over mouldings.
e. Dressing over glass and glazing bars, corrugated roofing, roman tiling, pantiling and
similar materials, dressing over drips and rolls.
f. Bossed burned, brazed or capped ends, angles and intersections to rolls, hollows,
condensation channels and mouldings.
g. Dressing into outlet pipes, dishing to gullies and the like.

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