Page 297 - Masonry and Concrete

Paving

296 CHAPTER EIGHT

The risers are formed by ripping 2 8 or 2 6 lumber to the exact
riser height and cutting them to a length that will fit between the side
forms. The bottom edge of the riser form must be beveled so that the
entire surface of the tread is exposed for troweling and finishing. Start-
ing with the top step, nail or screw the riser forms between the side
forms using double-headed nails or screws to make form stripping eas-
ier. Step forms may often have to resist a considerable amount of
weight from the concrete, so they should be braced and shored ade-
quately. Shore the side forms with 1 4 or 2 4 braces, and for steps
3 ft. or more in width, reinforce the riser forms to prevent them from
bulging. Drive a stake near the center of the bottom riser, nail a 2 6
to the stake, and use small cleats to hold the risers firmly in place (Fig-
ure 8-20). Finally, nail a cross tie between the two side form stakes
nearest the wall.
To prevent the concrete from sticking to the wall of the house, paint
or trowel a coat of mastic onto it. This will form an isolation joint and
keep the concrete from cracking along this intersection when it shrinks
as it cures. To reduce the volume of concrete that will be needed, you
can fill the center portion of the step form with compacted soil, gravel,

STAKE

2 4 CROSS TIE
2 2 CLEATS
2 6
STAKE

BEVELED
MASTIC COATING RISER
TO PREVENT BOND FORMS

FIGURE 8-20

Riser cleats.

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