How to Replace Concrete Blocks Drill a pattern of holes into the block with a masonry bit. Demolish the cinder block with a hand sledge hammer and a cold chisel. Sweep the newly formed gap in the wall with a hand broom. Mix a batch of mortar in a bucket or tub, following the manufacturer's directions. Mix together in a bucket one part Portland cement, three parts sand and enough water to make a stiff patching compound. Fill the hole with the patching compound. Use the corner of a trowel or your finger to pack the compound into the hole, making sure it is completely full. The concrete blocks that are used to build block foundations are hollow. After the concrete blocks are laid, the voids can be filled with a cement-based mortar or poured concrete that contains small pea gravel. If the builder does this, the filled concrete block walls become nearly identical to poured concrete walls. Drill a hole in the 4 corners of the mortar. Use a chisel to get a small line started then whip out your masonry saw and cut along the lines to pop that bad boy out! Or if you feel like taking a long time and going through a lot of bits, you could use a dremel and a chisel. The openings are called “cells” and one reason they are there is because they make the blocks lighter and easier for a mason to handle. But the primary purpose of the cells is that they align from top to bottom of the wall when laid, and enable a builder to fill some cells with grout/concrete to strengthen the wall.
Put on the hard hat, safety goggles, heavy gloves and dust mask. Strike the top of the wall with your sledgehammer, breaking the blocks into smaller pieces and working your way down the column about 2 feet wide. Cinder blocks are brittle so beware of flying bits of debris.
Cinder blocks require a durable paint to hold up to wear and tear. Latex paint with acrylic will provide the best coverage and the smoothest application for both smooth and split-face cinder blocks. If the paint will be on exterior blocks, select a paint that is also weatherproof to prevent damage from the elements.
How to Tuck-Point Brick and Block Foundations 1Chip away cracked and loose mortar using a slim, cold chisel and a hammer; remove the existing material to a depth of approximately half an inch. 2Prepare your mortar and allow the mix to set for about five minutes. 3Brush the joints with fresh water.
What Causes Stair-Step Cracks? The cause often boils down to moisture issues, or excess pressure on a certain part of the wall. This could be caused by gutter issues, or some type of fault in your drainage system. Therefore, moisture is not traveling away from your home's foundation as it should.
Spray the crack thoroughly with the garden hose. Fill the crack with mortar using a small, sharp trowel to force the mortar into the full depth of the crack. Treat the crack as one long joint, filling cleaned-out joints and the gaps in broken bricks or concrete block evenly all along the crack.
One further point to note is that you should never remove more than 2 bricks at once. If you have quite a few to do, replace 2 and leave them to cure correctly for at least a week before tackling any more.
It may take 5-10 years, but once the exterior waterproofing coatings and damp-proofing membranes deteriorate, the cinder blocks will be on their own to fight against negative side water pressure.
Concrete and plaster are porous materials; water can penetrate them, and in fact cinder block is more or less a sponge for water. In addition, the mortar used to build the wall will have only just cured completely after three weeks, and while it's curing it will actively accept water.
Water is the primary cause for most crumbling concrete. Whether from flooding or from repeated rains, water eventually wears down the structure of a cinder block from the outside, causing it to flake off and crumble. If a block has not been properly cured, water can also infiltrate the interior of the block.