Retaining walls serve different purposes around your yard, and these include keeping the soil from spilling over a steep slope. These walls are indispensable in building walkout basements, sunken patios, and other hardscapes that involve the ground elevation’s abrupt separation.
You can also find these retaining walls in public gardens and parks, where they serve as retainers for decorative landscaping elements, statues, and plants.
If you’re planning to do retaining wall installation on your property, the first step is to check with the local building authority. You see, building retaining walls can affect your neighbors and also alter the area’s water flow, so you might need to get a building or zoning permit.
Ordinances and local building codes vary between cities and communities, so you need to be keen on this part. It would also be helpful if you can check with your local utility company if there are buried electrical wires that might get in the way of your wall.
Another thing to consider is the retaining wall materials to use. Since you are building a structure, you need to ensure its durability and structural credibility. Given this, it’s essential to only use high-quality materials.
- Planning is needed
- Don’t: Forget to consult with local authorities
- Do: Carefully select the retaining material that will work best for your project
- Do: Always start building a strong foundation
- Do: Level the surface as you lay the blocks
- Do: Design your retaining wall to slope at a minimum rate
- Do: Make drainage provisions
Planning is needed
Retaining walls may look simple, but they undoubtedly require intensive planning — and sometimes the expertise of licensed engineers — just to keep the wall’s shape. Know that the soil will get heavier, especially when it gets soaking wet from rainstorms.
This only means that a simple retaining wall that should stand 4 x 15 feet has to support around 20 tons of pressure from the soil. As you add more foot of wall height, the soil pressure also substantially increases.
When you miscalculate your wall plan, you might get a weak wall that might bulge or, worse, build a wall that might collapse altogether. For this reason alone, it’s a must that retaining walls that are meant to raise more than four feet has to be designed and built only by the pros.
If you only plan to build shorter walls, this can be designed and constructed by DIYers with basic construction and wall-building knowledge. If you’re eager to get your hands dirty and you only intend to build a shorter wall, these basic do’s and don’ts will help you kickstart your project.
These guidelines will also help those who choose to hire pros because it will give them a comprehensive knowledge of the rigors and demands of the project.
As mentioned above, your retaining wall can impact your neighbor’s water flow. This is why, in most communities, homeowners are required to get a permit before they start constructing.
This means you need to submit your plan for your retaining wall and wait for the authorities to conduct a property inspection to ensure that the structure you’re building won’t start any drainage problem.
Do: Carefully select the retaining material that will work best for your project
You can use a variety of materials to build your retaining walls. You can use bricks, natural stones, or even poured concrete. If you’re taking the DIY route, go for manufactured blocks specifically designed for retaining walls.
These blocks have an accompanying locking flange along its bottom edge to secure the blocks between rows. You won’t have a hard time locating these blocks as they are easily found in virtually all garden centers and home improvement stores.
Do: Always start building a strong foundation
You have to take note that your retaining wall will only be as strong as its accompanying support system. If you plan to build a four-foot retaining wall from stacked-block, you can settle and shift quickly with a trench filled with three inches of crushed rock.
The trench’s extra depth will depend on the wall’s proposed height. Never use compact topsoil as backfill since it will easily break down and settle, building a water-capturing basin at the back of your wall. Go for gravelly or sandy materials since these materials compact better.
Do: Level the surface as you lay the blocks
The first row of blocks will set the stage for the subsequent blocks you will stack to build your wall. You should, therefore, make sure that it’s perfectly even and leveled. Otherwise, the next rows won’t be level as well. You see, this can lead to an unattractive and lopsided wall.
To make sure that your wall is well-leveled, use a four-foot carpenter’s level. This can ensure that the gravel layer underneath the first row of blocks is even before your resume setting the blocks. Note that any discrepancy will indeed show up in the upper levels of the wall.
Do: Design your retaining wall to slope at a minimum rate
A retaining wall that leans towards the soil it retains is not likely to push soil pressure than bare vertical walls. When you’re designing and building your wall, make sure to do so at a minimum rate of about one inch per foot of height.
The good news is if you work with retaining wall blocks, it’s effortless to achieve the so-called step-back construction. Just let the locking flange of each block guide you to click the block into position.
Do: Make drainage provisions
Every retaining wall’s natural enemy is groundwater. When groundwater saturates clayish soil, they usually swell and apply excessive pressure on the wall’s backside. To keep your wall from failing, make sure to allocate drainage provisions when you’re about to build your retaining wall.
All you have to do is backfill the space behind every block with crushed rocks before installing a flexible raw perforated drain pipe or drain tile at the wall’s base. This will create an escape route for the spilling groundwater.
The said pipe will then carry the water to the end of the wall to harmlessly drain away. The drainpipe’s end should also exit on every end of the retaining wall. To camouflage the pipe’s appearance, you may cover it with crushed stones.
Whether you’re a DIYer or not; these guidelines offer valuable insights on improving the way you plan, design, and build your retaining walls. Make sure to keep these in mind to ensure they are sturdy, functional, and will last for as long as possible.