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Balustrades are prone to decay and need frequent
inspection and painting.
Replace all woodwork with the correct historic sizes. Old
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lumber dimensions are often larger than modern dimensions.
Small differences will be obvious when the new work is in
place. New millwork for cornices, balustrades, and other
such features is available from millwork firms that
specialize in historic work.
Inspect lightning rods mounted on roofs. Install
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additional rods on roofs if required by code.
4.8.1 Roofing Materials. A wide range of materials were used
on historic roofs. Repair or replace in-kind if the roof is
visible.
Copper Roofs. These are among the best roofs but are very
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expensive. It is usually better to allow new copper roofs
and flashings to weather naturally than to use chemical
washes to age them.
Slate Roofs. A good slate roof can last 50 to 100 years,
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but slate varies in quality. Historic building roofs
constructed of inferior slate will need earlier
replacement. Slate roofs are easily damaged by impact
(such as from falling tree branches or workmen walking on
the roof) and fire.
Repair slate roofs by replacing only the damaged
slates. If the deteriorated area is large, remove the
slates and discard any broken ones. Reuse old slates
in the areas that show, and install new ones
elsewhere.
Do not use iron or steel nails on slate roofs. The
nails will eventually rust, and the slates will fall
off. Copper nails are best, but galvanized nails can
be used if copper won't penetrate the slate.
Do not walk on slate roofs.
Do not "torch" (fill in between and beneath slates
with mortar) . This keeps moisture from evaporating
and can cause wooden battens and rafters to rot.
Remove organic growths such as moss, algae, and
lichens.
Tile Roofs. Barrel tile (Spanish tile) and flat tiles
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also have a long `potential life.
Use galvanized nails to prevent corrosion damage to
tiles. Watch for acid and frost damage.
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