Care and maintenance of block retaining wall

Concrete block retaining walls require care and maintenance. With any newly built retaining wall, there are maintenance aspects that are important to watch for after the wall is completed. Provide this information to the property owner when a project is complete.

 Basic wall maintenance areas:

1.Site grading

2.Stormwater and services water management   

3.Surface treatments

4.Wall performance

5.Weed growth

 

SITE CONSIDERATIONS

Every newly built retaining wall has soils or backfill placed behind, and sometimes below, the wall and compacted during construction. Some extra settling is quite common after the wall is completed. Inspecting the wall each spring for any unusual or excessive settling can save you from a potentially large problem.

One of the most important items affecting the wall is the management of services and storm water in the vicinity of the wall. Unexpected wetting of the compacted backfill behind the wall by either a broken service pipe or poorly managed stormwater can lead to stress, excessive movements and possible failure of the wall. This is the single most common factor leading to problems with these walls.

All retaining walls should be designed and built to route water around or away from the wall face. Once an area behind the wall begins to settle, water goes to work to enlarge that area. If a low spot is neglected behind a wall, each new rainfall will collect water and work its way down behind the wall. If the area behind the wall is flat, this can create a pool above the wall, and this pooling effect turns the soils soft. If the wall wasn’t designed or engineered to hold up the added weight, wall failure could occur.

Preventing this problem is easy. Inspect walls each spring. Look for low spots and areas that have settled. Pull back the landscape mulch or sod on the surface and add enough fill to bring the drainage back to its proper level. This will ensure a lifetime of performance from the wall.

LANDSCAPE MAINTENANCE

Once a new block retaining wall is complete, the surface areas surrounding the wall that were disturbed during construction are typically finished with some type of landscape treatment. This might include paving, landscape plantings, mulch, sod or seed for turf, or some ground cover. These surface treatments provide an important function for the wall, as they capture and route the water from each rainfall.

These surface treatments will need to be checked each spring until they are completely established. Walk the site carefully, and look for areas that aren’t in proper condition. Replace bad sod, reseed bare areas, and work with the ground covers to encourage growth and coverage. Look for areas of erosion, ruts and channels on the surface, and re-landscape as necessary. A little work each spring in the areas surrounding the retaining wall will prevent erosion from becoming a problem and will also enhance the landscape around the wall. 

WEED GROWTH

As with concrete and asphalt pavement, a segmental retaining wall can let an occasional weed grow in its face. By plucking the odd weed that may have found its way into the wall, walls can be kept weed free. Walls may also be sprayed once annually just like lawns.

It is important to spray joints in hardstand and channels above wall. This will prevent separation in joints, causing storm water to erode and penetrate backside of block wall.

WALL INSPECTION

Retaining walls are made to last a long time. The concrete units are designed and produced to handle tough winter weather and long, hot summers. They won’t rot or decay.

Each spring, complete an inspection of the actual wall. Take a few minutes to check out the wall, including the blocks and caps. Begin by looking for any movement, bulges or rotation in the wall from the previous season. If drainage or erosion problems are not corrected, some wall movement could occur. At the sign of any significant forward movement or rotation, get a professional block retaining wall contractor or qualified engineer to evaluate the movement and determine the cause.

MAINTENANCE TIPS

Follow these simple maintenance steps to ensure long-term performance from your retaining block wall:

1.Thoroughly inspect the wall every year.

2.Correct any settling or grading problems around the wall.

3.Maintain the landscape surfaces around the wall.

4.Maintain service piping close to walls and insure storm water is channeled away from the wall in an effective manner, to ensure no erosion of fill can occur.

5.Take notice of any wall movement — settling, bulging or rotation — and then take proper corrective measures. If in doubt contact a professional block retaining wall contractor or qualified engineer

6.Control weed growth between joints of channels and hardstands near wall and weed block retaining wall as necessary.

 

EFFLORESCENCE

There is a chance that a few weeks or months after a wall installation, a white haze may appear on the surface of the blocks. This is known as efflorescence. There is no reason to be concerned because the blocks are experiencing a natural process. The condition will usually correct itself with time and exposure to the elements.

THE CHEMISTRY OF EFFLORESCENCE

All concrete products contain cement which produces lime or water-soluble calcium oxide. Lime can also be in the aggregates or soil. Although concrete segmental retaining wall blocks are solid, strong and very dense, they contain millions of microscopic capillaries that run from the interior to the surface. Moisture from rain, sprinkler systems or dew enters these microscopic capillaries. Calcium oxide inside the block reacts with the water in the capillaries and forms calcium hydroxide. This rises to the surface, reacts with the carbon dioxide in the air and forms a white haze of calcium carbonate.

When moisture on the surface evaporates, the white haze of efflorescence becomes visible.

ELIMINATING EFFLORESCENCE

Most producers of segmental retaining wall blocks put chemical additives in the concrete to reduce the likelihood of efflorescence. In most cases, they do the job. However, completely eliminating the chance of efflorescence isn’t possible because it’s a natural by-product of hardened concrete. It will stop when no more calcium hydroxide is available to move to the surface.

REMOVING EFFLORESCENCE

There are cleaners available that can remove efflorescence. Consult your dealer to find an appropriate cleaner. Cleaning should be performed immediately after efflorescence has appeared. It may reappear as long as the chemical reaction continues, and cleaning may need to be done until efflorescence has stopped.

Most cleaners contain acid and detergents; be sure to follow all label directions and environmental regulations. Careless or improper cleaning can result in injury, damage and discoloration on the surface of the concrete block. Always conduct a test in a small, inconspicuous area before applying any cleaner to the entire wall.

 

Back to Top