3.22 GABLE WALLS

When building a gable, stack the blocks to the top in pyramid fashion, each course being shorter in length than the course below or as necessary to establish the gable slope.

Snap a chalk line from the low end of the gable to its peak. Lay the top edge of 1x4’s along that line, on both sides of the block, securing them to the strapping paddles with course thread drywall screws.

Using a fine tooth hand saw or electric saw, cut off the excessive block above the 1x4’s (chalk line). With a minimum slope and a relatively dry slump (around #5) the concrete can be poured directly into the apex portion of the wall and smoothed along the slope line.

For a more severe slope, use 1x12’s, or certified OSB/plywood, placing it across the top of the block and securing it to the 2x4’s covering the opening (similar to using a window sill buck). Cover only a few feet at a time. Pour the concrete, allowing it to flow and fill beneath the covering board. Repeat this process, working your way up the gable slope. You may need to pre-drill holes AB placement.

Remember to insert anchor bolts appropriately so that when the concrete has hardened and when the plywood or 1x12’s are removed, the anchor bolts will remain securely in place. Finally, bolt on the permanent sill plate, using the in place anchor bolts, and a sill gasket to avoid air infiltration.

Some gables can also be constructed on the ground and hoisted into place. Gluing can be beneficial in this application. See safety note