Masonry Magazine January 1979 Page. 23
FLASHING
WEEP HOLES
REINFORCED
BRICK LINTEL
CAULKING
CAULKING
Metal Casement Window
FIG. 17
METAL Z TIES
WEEP HOLES
CAULKING
CAULKING
FLASHING
WEEP HOLES
Commercial Metal Window
FIG. 18
FLASHING
STEEL ANGLE
LINTEL
METAL Z TIES
FLASHING
One way to avoid parapet problems is to eliminate the parapet. However, they are frequently required by building codes, or architectural considerations.
The detail shown in Fig. 14 is suggested as one method of building parapets. For cavity wall construction, it is recommended that the cavity continue up into the parapet, thereby providing some flexibility between the outside wythe and the inner wythe. Expansion joints should extend up through the parapet. In addition, the parapet wall should be reinforced and doweled to the structural frame or have an additional expansion joint spaced between those in the wall below. Expansion joints should also be placed near corners to avoid displacement of the parapet. Parapet copings should provide a drip on both sides of the wall. Metal, stone, and fired clay copings of various designs usually provide this feature. The back side of the parapet should be constructed of durable materials, preferably the same material that is used in the front side of the parapet. They should not be painted or coated, they must be left free to "breathe." Unless copings are impervious with watertight joints, place through flashings in the mortar bed immediately beneath them and firmly attach the coping to the wall below with anchor bolts.
FLASHING AND WEEP HOLES
Flashing is installed in masonry construction to divert moisture, which may enter the masonry at vulnerable spots, to the outside. In areas of severe or moderate exposures, flashing should be provided under horizontal masonry surfaces, such as roof and parapet, or roof and chimney; overheads of openings, such as doors and windows; and frequently at floor lines, depending upon the type of construction.
To be most effective, the flashing should extend through the outer face of the wall and be turned down to form a drip. Weep holes should be provided at intervals of 16 in. (406 mm) to 24 in. (610 mm) maximum to permit water accumulated on the flashing to drain to the outside.
If, for aesthetic reasons, it is necessary to conceal the flashing, the number and spacing of weep holes are even more important. In this case, the spacing should not exceed 16 in. (406 mm) o.c. Concealed flashing with tooled mortar joints can retain water in the wall for longer periods of time, thus concentrating the moisture at one spot.
To prevent any possible moisture infiltration and to promote cavity drainage, place the bottom of the cavity wall above the finished grade, and avoid placing earth over the weep holes during landscaping. With basement construction, it is important to use through-wall flashing at the bottom of the cavity to prevent moisture from penetrating the inside surface of the basement wall, see Fig. 15. In basementless construction, the flashing at the dampproof course may also serve as a termite shield.
DOORS AND WINDOWS
Stock sizes of windows and door frames are used in cavity walls, although sometimes additional blocking is needed for anchorage. Avoid solid masonry jambs at windows and doors in cavity walls. However, for steel windows, the jamb must be partially solid to accept most standard jamb anchors. Wood or steel surrounds must be used to adapt non-modular steel case-