Examples of Construction Details for Masonry Structures Requiring Little Structural Calculation

Examples of construction details for masonry structures requiring little calculation are given in the sections and figures below. These details are  generic in nature. These can be supplemented by the details provided in NCMA and BIA technical notes.

1. Overall modularity:

a. Overall modularity of the CMU wythe will be satisfied provided that the interior nominal dimensions of the CMU wythe are an even number of feet, and the units have a nominal thickness of 8 in. The exterior dimensions of each CMU wythe will be an even number of feet, plus 2 times 8 in. (two nominal CMU wythes). Any such exterior dimension can be laid out without cutting CMU, because the interior dimension is an even number of feet (some number of 16 in. units plus perhaps one 8 in. halfunit), and the exterior dimension is obtained by adding another nominal dimension of 16 in.

b. Overall modularity of the clay wythe will be satisfied given the above, plus a 2-in. nominal air space and nominal 4 in. clay units. The exterior nominal dimensions of each clay wythe will be an even number of feet (see above), plus 2 times 8 in. (two nominal 8-in. CMU wythes), plus 2 times 2 in. (two nominal 2-in. air spaces), plus 2 times 4 in. (two nominal 4-in. clay wythes). Any such exterior dimension is an even number of feet, plus 16 in. plus 4 in. plus 8 in., or an even number of feet plus 28 in. This exterior dimension can always be made with nominal 8-in. units plus a nominal 4-in. half-unit. Overall modularity in this example is shown in Fig. 2.19.

2. Connections between floor slab and walls. These are exemplified in Fig. 2.20.
3. Connections between walls and roof. Examples of connections between walls and roof are exemplified by Figs. 2.21 and 2.22.
4. Locations of control joints in CMU wythe, and locations of expansion joints in clay wythe. An example of these is shown in Fig. 2.23.

The CMU wythe has control joints above and below windows, and above doors. The control joints above the windows and doors are normally offset from the jams so that the lintels produced by these joints can have 8 in. of bearing at each end. The control joints below the windows are normally even with the window jams because there is no need for an offset. The clay wythe has expansion joints within 18 in. of the corners, and at window and door openings. If the lintels in the clay masonry wythe are supported on the CMU wythe (fixed lintels), the expansion joints at openings can be even with the jambs. If the lintels in the clay masonry wythe are supported only by the clay masonry wythe (loose lintels), the expansion joints above openings must be offset from the window and door jambs so that the lintels produced by these joints can have 8 in. of bearing at each end, just like the lintels in the CMU wythe.

5. Wall sections at windows. Details of wall sections at windows are shown in Fig. 2.24.

The left and right figures correspond to fixed lintels and loose lintels, respectively. The details are identical except that in the fixed-lintel detail, the lintel is supported by the CMU wythe (note the anchor bolt), whereas for the loose-lintel detail, the lintel is supported by the veneer wythe. In each case, the window head has weepholes in the veneer, and flashing with end dams. The window foot has an inclined masonry or precast concrete sill, with flashing and weepholes underneath. The wall has weepholes and flashing at the top of the foundation. In these details, the roof connection or parapet are not shown. Sections at doors are the same, except that the door sill is at foundation level.