Winter temperatures below 40 degrees Fahrenheit require a cold weather masonry construction plan. It is at this point that the hydration of the cement slows or stops and can fail after its eventual curing. Grout between the concrete blocks can crack or flake off if it freezes or becomes too cold before it sets fully, leaving the area compromised and unsightly.
Things You'll Need
- Poly film
- Clear tape
- Propane heaters
- Measuring tape
- 2x4 form boards
- Wood stakes
- Concrete mixture
- Concrete blocks
- Concrete mortar
Measure the area of your intended wall and build a scaffold that will completely enclose the area. Remember, it must be tall enough to accommodate the full height of the wall. Drape the scaffold frame with poly film and seal gaps in the film with clear tape. Turn on propane heaters inside the covered scaffold to raise the temperature.
Dig a footer for the concrete block wall that is twice as deep as the thickness of the wall and twice as wide. A 1-foot-thick wall requires a footer that is 2 foot deep and 2 feet wide. Outline the footer with 2x4 form boards and secure them in place with wooden stakes.
Prepare the concrete according to the manufacturer's instructions and pour it into the footer until it reaches the top of the form boards. Pull a 2x4 across the top of the form boards to remove any excess concrete and fill in small holes. Allow the concrete to set for 24 hours, ensuring that it stays warm by leaving the propane heaters running for the duration of the curing time.
Determine the number of concrete blocks you need by laying a dry run. Beginning with a finished end corner block, lay the first block at the corner. Leave a 3/8-inch gap and then place a cut block. Continue, leaving a 3/8-inch gap between the concrete blocks until you reach the other end of the footer. Remove the blocks then prepare to lay them permanently.
Spread a layer of concrete mortar onto the footer with a trowel to cover a distance of three or four blocks. This mortar should be 1 inch thick and the same width as your blocks. Drag the tip of the trowel through the center of the mortar line to create a small "V."
Set the corner block first, ensuring that it is a finished end block and squared properly on the footer. If this first block is off, then the whole wall will be off. Nestle the block gently down into the mortar.
Spread a 3/8-inch layer of mortar onto the end of the block. Spreading the same amount of mortar each time will ensure that the blocks are spaced evenly. Continue in this manner until you have reached the end of the first course.
Ensure that the blocks are properly aligned by tapping them gently to adjust them as needed. Remove any excess mortar from the joints and the bottom edges of the concrete blocks with the trowel.
Lay the second course of blocks in the same manner as the first course. Continue laying courses until the wall is the desired height.
Allow the mortar to cure for 24 to 48 hours, ensuring that the temperature inside the enclosed scaffold area remains at 32 degrees Fahrenheit or higher. Once the concrete mortar is completely cured, the scaffolding can be removed.
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