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Steel Designers' Manual - 6th Edition (2003)
28.3.2.3 Weather-resistance
/ Ø7j7/7
(a) __
seal filler
I, 4
seal gasket
drain to
bottom
membrane
(PVC, thin metal, etc.)
Joints 861
It is important to consider the degree of weather-resistance required for a joint. In
this respect, joints can be classified (in a somewhat over-simplified form) into three
types (see Fig. 28.12(a), (b) and (c)):
(a) ‘Closed’ joint, with a filler material and exterior sealant,
(b) ‘Closed’ joint, with a compressible gasket and exterior sealant,
(c) ‘Open’ joint, with a flexible membrane seal, and arrangements to drain rainwater,
etc. from the inside surfaces of the joint which are ‘open’ to the weather.
Where appropriate, arrangements should be made at joints in buildings for continuity
or sealing of insulation and vapour barriers, etc. to prevent formation of
condensation, or loss of heat.
In structures where there is likely to be water in contact with the structural
envelope, e.g. structures buried in ground which has a high water table, or waterretaining
structures, flexible waterbars are usually incorporated at construction and
movement joints. These have the effect of interrupting the path along which any
water present has to travel.
Figure 28.13(a), (b) and (c) are typical of wall details in reinforced concrete or
brickwork construction. A typical joint detail for steel cladding in a building is
Fig. 28.12 Weather-resistance of joints: (a) closed, with filler, (b) closed, with gasket,
(c) open, with membrane