QA

Question: How To Place Retaining Wall Blocks

Does the lip go up or down on retaining wall blocks?

Push the retaining wall block back so the lip hangs below the first retaining wall block row’s surface.

Should retaining wall blocks be staggered?

Remember to leave a small gap between your retaining wall and the soil for the drainage rock or reinforcement grid. As you begin to build the wall higher, it is important to stagger or offset each level.

What keeps retaining wall blocks from moving?

Your retaining wall will only be as strong its support system. For a stacked-block retaining wall that’s no higher than four feet, a trench filled with three inches of crushed rock will help keep the wall from shifting and settling.

What side of block goes up?

Concrete block webs are wider on one side. The wide side should face up because it provides a larger bed for the mortar. This reduces waste, minimizing the amount of mortar that falls off the web. It’s also easier to handle the blocks when you grip the wide side.

Does a 2 foot retaining wall need drainage?

These walls need a drainage system regardless of the wall height. If there are poor draining soils such as clay behind the wall, there needs to be drainage incorporated the wall system. Clay when wet is very weak, so it is essential to provide a way for water to escape from behind the wall.

How do you lay a block on a slope?

Start placing the second row of blocks on the lowest level. Stagger each block so that no joints align. Push the back lip on the blocks firmly against the blocks below them. Continue setting blocks as you work your way up the various levels on the slope.

How do you stagger concrete blocks?

Running bond requires that the blocks be staggered over the top of each other. For example, if you are laying one long wall, the first row of blocks will be laid, then the blocks on top of that row will all be staggered over the previous blocks — the end of the top block will stop in the middle of the previous block.

Do you need landscape fabric behind retaining wall?

Whether the wall is made from stones, bricks or wood, it is important to provide a barrier between the building blocks and the soil. Landscape fabric is thin and sturdy and is a simple way to preserve a retaining wall’s construction.

How deep should a footing be for a retaining wall?

The general rule of thumb is to bury about one-eighth of the height of the wall. For example, if your wall will be three feet (36 inches) tall, the first course of blocks should start five inches below soil level. The gravel base should start three inches below this.

Can you build a retaining wall on concrete?

While you can build a retaining wall on concrete, it isn’t that straightforward. If you have an existing concrete base, you cannot just build your wall on top of it. Without being secured into the concrete, your wall will slide due to the soil pressure against the wall.

Can you use sand as a base for a retaining wall?

To keep the blocks on your retaining wall level and structurally sound, you need a base layer of several inches of well compacted, sharp gravel. Be sure to use coarse builder’s sand, and tamp it down firmly to keep the sand from shifting and settling after the wall is built.

What do you put under landscaping blocks?

Backfill Use crushed gravel to fill in the back and sides of your blocks. Backfill helps with water drainage. Compact the backfill before starting on the next row of blocks. You should clean and sweep the top of each row before placing the next one.

Can you lay block on dirt?

Cinder blocks are sometimes set in cement but you can also place them directly into the soil. They are solid and heavy enough to hold down weeds and resist shifting.

What is the mix for laying concrete blocks?

Measure out 4 parts sand and 1 part cement, and use a shovel to mix it dry on the platform. Make a crater in the middle of the mix, and add a bucket of water and the appropriate amount of lime or mortar additive. Mix thoroughly by shoveling the bottom of the mix to the top and repeating.

Why is there a lip on retaining wall blocks?

A lip on the back of each block creates a uniform setback as each course is added. This design causes the wall to angle slightly back into the slope, further improving its holding power.

Does a 4 foot retaining wall need drainage?

Any reinforced wall or walls over 4 ft. (1.2 m) in height or with slopes or other surcharges above the wall will need a toe drain. In all cases wall rock is located within the cores of the block and a minimum of 12 in. (300 mm) behind the block.

How tall can a retaining wall be?

Height variations can differ from state to state. but here are some rough guidelines to follow: * In New South Wales, you need permission from council to build a retaining wall higher than 600mm from ground level.

How thick should mortar be between blocks?

Mortar and mortar joints The mortar joints used in concrete block and brick construction are usually 10 mm thick. For AAC block construction, a special type of mortar is used (2-3 mm) and this is a pre-mixed cement-based product with higher quality than normal mortar.

How can I make my concrete block walls look better?

Surface bonding cement, used to build dry-stack block walls in place of mortar, can be used to create a smooth surface on concrete block. It’s a waterproof, flexible Portland cement reinforced with fiberglass. One of the benefits is that you can add color to the cement, eliminating the need to paint over it.