July 12, 2019

How strong is an Allan Block retaining wall?

Written by Kyle Huerd

A quick answer is VERY!  To give you an idea, all Allan Block products have to meet an industry standard which is governed by ASTM 1372.  This has a minimum compressive strength of 3000 psi.  Because AB is striving to be Always Better, we hold our manufacturers to a higher standard.  With that being said, the producing partners of Allan Block may be required to manufacture closer to 4000, 5000, or even higher in compressive strength.  This is because Allan Block wants to provide the best quality product on the market and find producing partners who have the same goals.

Building material products are much stronger as they are the backbone of the construction industry but to put it into perspective, a half ton pickup truck can carry a load that is 33% of the total weight of the vehicle, the human body can carry an estimated 135% of the person weight, and an Allan Block has the strength to carry 7500% of its self-weight.  Allan Blocks may not be structural blocks for a vertical load, but their strength is incredible which allows your Allan Block wall to last a lifetime!

Although this is a longer answer than the simplified, VERY, from the opening statement, now you know that Allan Block retaining walls are strong.

July 5, 2019

How Do I Care for my Retaining Wall?

Written by Kyle Huerd

Retaining Walls, like everything else on your property, 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. Allan Block walls will need far less care than other types of retaining wall products, but there are some key factors to watch for.
  • Site Grading
  • Surface Treatments
  • Wall Performance
  • Salt Spray

Site Grading

 Every newly built retaining wall has soils - backfills that are placed behind and sometimes below the wall and compacted during construction. It is quite common for some extra settling to take place after the wall is completed. If you inspect the wall each spring for any unusual or excessive settling, you can save your wall from a potentially large problem. All retaining walls should be designed and built to route water around the wall face. Once an area behind the wall begins to settle, water goes to work to make that area deeper and bigger. If a low spot is neglected behind a wall, each new rainfall will collect water at that spot and work its way down behind the wall. If the area behind the wall is flat, this can have the effect of creating a “swimming pool” above the wall. Preventing this problem is easy. Inspect your wall each spring. Look for low spots and areas that have settled. Pull back the landscape mulch or sod on the surface and add enough new fill to bring the drainage back to its proper level. By keeping these trouble spots filled, you can ensure a lifetime of performance from your Allan Block wall.

Surface Treatments

Another common maintenance problem with retaining walls is the lack of proper surface treatments. Once a new retaining wall is completed, 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 type of ground cover. Often overlooked as part of the total wall design, these surface treatments provide an important function for the wall. They capture, control 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, re-seed bare areas, 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 bit of work each spring with the areas surrounding your retaining wall will prevent major erosion from becoming a problem and will also enhance the landscape of your Allan Block wall.

Wall Performance

Allan Block walls are made to last a lifetime. The high strength concrete units are designed and produced to handle tough winter weather, and long hot summers. They won’t rot or decay. With tens of millions of square feet of Allan Block sold and installed, we can say they truly do last a lifetime. With all that, we still recommend a spring inspection of the actual wall itself. Take a few minutes to check out the wall, including the blocks and caps. Begin by looking for any movement in the wall from the previous season. Properly built Allan Block walls will remain in place forever. However, if a wall is not installed correctly, or if drainage or erosion problems are not corrected, some wall movement could occur.  Check your wall each spring for bulges or rotation. Again, this can only happen if the wall was not properly installed, but nonetheless, it is good to watch over the wall performance. If you see any significant forward movement or rotation in your Allan Block wall, get a professional contractor or engineer to evaluate the movement, and determine the cause.

Salt Spray

In northern climates, Allan Block products are produced with a concrete mix design that is resistant to the harsh effects of the freeze-thaw winter cycles. However, use of salts around an Allan Block wall could cause surface damage to the blocks or capstones. Look for pock marks or spalling on the blocks in areas where salts are used for winter ice control. Avoid using any salt deicers on or around your Allan Block wall. If you need to use deicers in areas around your wall, contact your local building materials outlet for a deicer that will not harm concrete. In cases where salt spray may exist, design the wall in such a manner that the snow melt and snow banks containing the salted snow are directed away from the Allan Block wall.

Maintenance Tips

Follow these simple maintenance steps to ensure a lifetime of performance from your Allan Block wall: 

  • Make a thorough annual inspection of the wall
  • Correct any settling or grading problems around the wall
  • Maintain the landscape surfaces around the wall
  • Take notice of any wall movement - settling, bulging or rotation, and then take proper corrective measures
  • Avoid use of salts as deicers around the wall
For more information on proper construction techniques, visit allanblock.com

June 28, 2019

What is Best Practices for SRW Design?

Written by Kyle Huerd

Think of a manual for an engineer, contractor, architect, or owner that provides the best scenario on retaining wall designs to navigate you from the beginning of your project to the end.  Not only will you find most of the answers for the questions that come up on your retaining wall questions, but the Best Practices really reduces the chance of wall failures as it is part of the Zero Wall Failures Initiative.  The document was written to provide that guidance to the designers around the world as we didn’t have much guidance on many key topics in the Segmental Retaining Wall Industry.  So not only does the document answer those questions, it is backed with over 30 years of field experience and testing to make your project a success! 

June 21, 2019

Are Heel or Toe Drains Necessary?

Toe Drain
Written by Jeremy Zeis

Retaining walls and water are almost always bitter enemies. If a retaining wall fails, there is a good chance that the reason for failure has something to do with water. That being said, routing water away from your retaining wall is a very important step in the design process.

A common question that we get is if the toe and heel drains are necessary on every design. The toe drain’s main purpose is to collect and expel incidental water that makes its way through the wall rock right behind the wall but shouldn’t be used as a main drainage system. The heel drain is used to route water that has migrated behind the wall away from the reinforced soil mass. 

Heel Drain
While we always recommend adding toe drains, heel drains are not always needed. For example, gravity walls don’t have a reinforced soil mass to route water away from, and a wall designed with no-fines-concrete doesn’t need a heel drain because the water will flow straight through the concrete mass.

The reason that Allan Block always recommends a drain is because there is always a chance that water will get behind the wall, and it’s very important for the water to have a safe exit path that avoids the wall. Here at Allan Block it’s our goal to see all retaining walls designed and built properly and now that you know the importance of toe and heel drains, you can help us reach that goal.

Learn more about water management and retaining walls at allanblock.com

June 14, 2019

Top Patio Designs using AB Courtyard by Allan Block

Written by Gerri Hansen

The AB Courtyard Patio Wall product uses concrete blocks to bring unique designs to your landscaping in many different applications.  This durable, versatile two-sided free standing wall system stacks simply together like kids building blocks.  Easily build panel and post type walls or applications like custom kitchens, BBQ surrounds, fire pits, bench seating and much, much more.

If you are looking for design ideas to upgrade your patio space, there are pre-designed patio packages and weekend projects ideas ready to fit needs.  All the packages offer complete instructions and video installation from start to finish.  These packages can fit right on your existing patio surface or built on a foundation and can be modified to fit any space with minor changes to the layout.  

The Allan Block line of retaining wall products also works well with the AB Courtyard products with matching colors and textures.  If you have an uneven backyard space, use the retaining wall products to level the space a raised patio and then top it off with a Courtyard wall above.  The two products blend together seamlessly.

There is a complete photo library available of backyard landscaping ideas using AB Courtyard that include patio enclosures, outdoor kitchens, ponds, planters, fire pits, seating and more.  With simple and detailed instructions, AB Courtyard should be the product of choice.

June 7, 2019

I am building stairs with my retaining wall, what are my options?

Written by Danelle DeMartini

Stairs help us gain access to vertical spaces, break up long stretches of wall and generally look nice. Choosing the right stair design for you space is important before you start construction.  Here are just a few options to get your design juices flowing.

Is your stairway short or long? You can breakup long stairways with landings, curves or switchbacks

Does your space allow for stairs to go alongside the wall or do you want to save space with a stairway within the wall? Do you want rounded steps or a more angular look?

Whatever design you choose, using an Allan Block retaining wall product allows you the opportunity to different textures for your design while making the installation process straightforward.  For more information on stair designs and stairway installation, visit allanblock.com.

May 31, 2019

How many steps do I need in my retaining wall?

Written by Danelle DeMartini

Stairs are important for getting us from one level to another, whether it’s inside your home or outside in your yard.  In most cases the stairs inside are already done for us when we buy a home, but those outdoor stairways can be great additions to our backyard spaces.

But where do we begin?  Before we can complete a design to at stairs to our outdoor space we first need to determine how many steps will be needed.  To do that, use this simple formula:

Measure the total height of the area (rise) and divide this by the height of the step (run).
Rise/Run = # of steps needed

On steep slopes, keep the steps tight together. On gentle slopes, increase the depth of the tread and length of the run or add landings to soften a long stairway.

Allan Block retaining wall blocks used for building raised patios or terraces are 8 in. So if the raised patio is 4 ft. tall and your steps are 8 in. high

48 in. rise/8 in. run = 6 steps needed

May 24, 2019

What types of fences can you build with AB Fence?

Written by Chad Julius

The AB Fence has been used in a wide variety of applications and the literature outlines some basic applications such as screening, containment, beautification and sound barriers. 

But let’s face the facts and realize you are constructing a fence for two reasons.  You either want to keep something out or something in. 😊

The “something” is what makes your application unique.  Examples of keeping something out include traffic noise, curious neighbors, security from vandals and the list can go on.  On the flip side, maybe you are just trying to keep your dogs in the yard or provide a safe place for your kids to play without worrying about them wondering off.  There are many ways to build the AB Fence to satisfy your application and create a beautiful solution. 
I would recommend that you take a look through the photo gallery on at allanblock.com to see some of the applications and projects that are featured. 

May 17, 2019

What are the capping options for AB Fence?

Written by Chad Julius

Capping the AB Fence is like the icing on the cake.  The structural requirements are done so now you are just putting the finishing options together.  Typically, the AB Fence is finished by using the AB Fence Cap Block. This is just glued on top of the panel and post blocks with a high-quality construction adhesive. 

The same cap is used for both the panels and posts to simplify the process. 
The real fun comes by creating by varying the panel and post heights.  We recommend the Castellated Finish for the AB Fence by constructing the posts one block taller than the panels. 

However, you can get creative and extend the posts even taller and have iron or steel fencing between them.  Whatever, you decide to do the AB Fence Cap Block is glued in place to finish the top of the panels and posts. For more information on capping and finishing options for your Allan Block Fence, visit our website at allanblock.com

May 10, 2019

Can I use AB Courtyard on top of my existing retaining wall?

Written by Chad Julius

Absolutely.  We have countless projects where Courtyard is used on top of the retaining wall.  You have got to check out some of the pictures we have of raised patios that show the AB Courtyard on top of retaining walls.  However, since it is an existing wall there needs to be some questions answered first.  It will depend on if that existing wall will remain structurally stable when the additional loads are applied.  Let me explain.  The Courtyard itself has weight, but so do all the people that will be standing on the patio that you are building as well.  The existing retaining wall must be able to withstand this additional weight or pressure before moving forward. 

Once the integrity of the existing wall is satisfied then you can simply install the AB Courtyard wall on top of the existing retaining wall.  The AB Courtyard does not require a footing and can installed directly on top of the cap or pavers for the patio. We would suggest adhering them to the cap for some stability, but it is not required since the AB Courtyard Caps are also glued once installed.  Check out the Courtyard Reference material on our website.