October 10, 2019

What do I need to know as I plan/design my retaining wall?

There is a lot of planning that goes into a retaining wall design when things begin to start moving forward.  To provide more information, you can visit the Allan Block Residential Retaining Wall Manual to help organize and formulate your plan. To summarize some of the main talking points, lets break it down into the following 5 items:

           Soils – What type of soils do you have at your project?  Are they sandy? Clay? Gravel?  This can increase the pressure on the wall, and require additional reinforcement depending on the height of your wall.  Since the purpose of the wall is to retain soil, this remains one of the most important aspects in the design.

           Slopes – Are there slopes above the retaining wall?  If the grade is going to slope above the wall, this is an added load and therefore may also require additional reinforcement.  Slopes above a retaining wall remain one of the largest loads possible; the steeper the slope, the more load the wall will carry.  What about slopes below the wall?  If there is a slope below the wall, then you will want to verify with your local engineer that global stability isn’t a concern, or that your wall will remain stable.  Slopes above and below a wall are an immediate red flag for a global stability concern.

          Surcharges – A surcharge can be anything above the wall that adds weight to the soil behind it.  This can be a parking lot, a driveway, a building, equipment, snow loads, or as mentioned above, slopes.  Anything that may be placed above the wall with a sizable mass to it is considered a surcharge.

      Water Management – Water is the #1 reason why walls fail.  With that being said, you will want to make sure your grades around the retaining wall don’t bring water towards it.  Instead, you’ll want to use berms and swales to guide water around the wall, keeping the soil behind it as dry as possible.

Examples of permeability in different soils and gravel.

      Retained Height – The height of the wall plays a major role.  As the height increases, more pressure is exerted on the wall.  Many local building codes govern when a retaining wall needs engineering and permitting, but even small walls can have issues if the previous notes aren’t planned for and taken into consideration.  As the wall increases in height, you will want to make sure you have additional reinforcement to make sure your wall lasts a lifetime!

These items may not be the only items to check and consider prior to construction of your retaining wall, but it is a quick list to run down as you begin to plan your wall project.

October 3, 2019

Count the Yard: Estimating Your Outdoor Project Materials

Are you thinking about building your next outdoor living space with Allan Block products? Do you have an idea what you want to build, but you don’t know how much material to buy? Allan Block has some great software applications to help you take your project to that next step.

AB Estimating Tool
Estimate all your Allan Block projects in one place with the AB Estimating Tool. This simple material estimator for retaining walls, patio walls, and concrete fences allows you to quickly and efficiently estimate the materials needed for large and small retaining walls, AB Courtyard patio walls and AB Fence sound and security fences (available in English and metric units.)
The AB Estimating Tool is a great resource for quickly generating material quantities that you can take straight to a contractor or hardscapes dealer to get your project started. Are you looking for something a little more visual? Do you want to lay out your project before you get a material estimate together?

With the AB Courtyard application you can choose from a variety of pre-designed patio packages or create your own patio design and receive project plans, elevation designs, material estimates, and installation instructions. You can even draw your project in 3D  (available in English and metric units.)

Ab Courtyard App
The AB Courtyard application walks you through the entire patio design process from start to finish. You can even watch step-by-step videos on the whole installation procedure.

September 27, 2019

New Contemporary Look in Retaining Walls

AB Aztec Collection
The Allan Block Aztec retaining wall blocks have a clean, smooth look to offer a contemporary style to any project.  The blocks are available in 4 different shapes and sizes that are all modular, they work great separately and when grouped together make beautiful patterns.   If you are familiar with the other block collections from Allan Block, the AB Aztec blocks are the same just with this new modern, smoother facing.  They are installed just the same so detailed installation and videos are available.  With the varying color blends and eye-catching flowing texture, this product offers the look of movement with impressive results.  

As with any of the AB retaining wall blocks, this system can build any size project from small garden walls to large engineered walls.  Easily create curves, corners, stairs, the options are open to your design.

If this is the look for your project, check out more information on AB Aztec today to create your perfect outdoor living area.

September 20, 2019

Vertical or Staggered Wall Ends – How do I Choose?

Written by Gerri Hansen

The AB Courtyard wall panels can be finished with a vertical end by cutting corner blocks, or by simply staggering the blocks back from the end of the wall to create a gradual step-down look.  For a no cut option I would recommend the staggered look.  This can be done by simply removing a block from the wall panel during installation, so the wall finishes short, then place the corner block.  The corner blocks can be flipped either direction to match the angle of the last block placed.  

On additional courses, continue to remove or leave off a block to again set the wall back in the distance desired, until the top height of the wall panel is achieved – no capping is needed.  If a larger stagger is created between courses, the AB Wall Caps may need to be cut to fill in any gaps created.  Measure the space and cut the blocks with a saw using a diamond blade and adhere to safety standards.

If a vertical end is desired, on every other course a corner block will need to be measured and cut to allow proper alignment. See the AB Courtyard reference guide for details and links to videos to help you choose the best option for your project.

September 13, 2019

How to design and build a retaining wall near a tree and not kill it?

Written by Jeremy Zeis

Three steps to make sure your tree survives retaining wall construction.

It’s time to design that retaining wall that you’ve been wanting for a while now, but there’s just one problem; your favorite tree is standing in the general area that the new wall will be. Construction can be a brutal process and you aren’t sure if your beautiful tree will be able to survive the stress that putting up a retaining wall can create. Well, fortunately, we’ve got some good news for you. Along with some proper planning, the following three steps can be used to ensure that your tree will survive well beyond the construction and installation phases of your new retaining wall.

1. Talk to an arborist.

            We may be experts on retaining walls, but when it comes to trees we’ve got nothing on arborists. These tree professionals are the perfect people to consult about any specific needs that your tree might have when it comes to surviving retaining wall construction. They’ll be able to give you a general idea of what impact the changes you’re making will have on the existing trees and how easy it will be for them to adapt. If asked, they can also share some tips and tricks to monitor how healthy your tree is and what you have to do if it’s showing any warning signs.

 2. Be mindful of your tree when designing your wall.

  Trees need space. With roots that grow out in every direction, trees can take up a lot of ground space, but how much do they need in order to stay healthy? The most important area of the tree’s space to protect is the Critical Root Zone (CRZ). The CRZ is where the majority of the tree’s major root systems begin. This zone can be estimated by tracing the canopy of the tree onto the ground (the dripline) as seen in Figure 1. If you want your tree to survive, it is important to design your wall in a way that avoids interfering with the CRZ This can be done by curving your wall around the zone.

3. Avoid the Critical Root Zone during construction.

Not only is it important to avoid the CRZ with your design, but it’s also important to be mindful of it during construction. In order to maximize the chances of your tree surviving construction, any of the following actions should be avoided within the CRZ if possible:
·       Any soil compaction
·       Changing grade
·       Parking heavy machinery
·       Material storage
·       Digging into soil and damaging the tree’s roots

As you can imagine, even if they take place outside of the CRZ, any of the above actions will still affect the tree’s health, just not as severely as if they happen inside of the zone. It’s also important to note that not all trees will react to changes in their growing environment the same way, so be sure to find out how your specific tree will be affected.

In addition to the three steps above, we encourage you to learn more about proper retaining wall construction so that your favorite tree and new wall can both live healthy lives for decades to come. 

September 6, 2019

Reaching for the Skies - How tall can I build with AB Fence?

Written by Chad Julius

Let’s start with the current record holder.  Our tallest AB Fence system built is located in South Hackensack, New Jersey and reaches a maximum height of 30 ft (9.0 m). For a complete write up you can check out the case study, Tallest Sound Barrier.  I would doubt we will see too many projects that will require a taller fence than that. 

Most of our fence projects range from 6 ft (1.9 m) to 12 ft (2.8 m). However, instead of focusing on the maximum height, let’s talk about what factors will influence the height.
  • Wind Pressure – based on climate information for your area and average wind speed is known.
  • Exposure to the Wind – fences that are constructed on shorelines and in open areas will be unprotected to the wind more than fences that are located around buildings.
  • Post spacing – this all comes down to the size of the panel area and how much pressure is being supported by the posts.
  • Concrete Strength – there are limits to the strength of concrete and too much pressure could cause cracking and failure.
  • Structural Steel Design – this includes the amount of steel located in the posts as well as the bond beams within the panel.  The more bond beams used the stronger the panel becomes.  

For more information check out the AB Fence Section at allanblock.com.  

August 30, 2019

Allan Block puts more $$$ back into your savings!

Written by Kyle Huerd
Although there are many styles and colors that can be completed with Allan Block retaining walls, the material cost is very competitively priced with other types of materials. 
Allan Block Retaining Wall

Without spending too much time getting off topic, let’s look at the least expensive route, timber retaining walls.  

timber wall


  • Tried and true over the last 50+ years.  
  • Materials readily available
  • Easy Installation


  • Life Expectancy (15-25 years)
  • Maintenance – seal coating wall every 3 – 5 years
  • Environmental disposal costs

Although you may have a significant up-front cost reduction, the cost of a timber wall over the lifetime of an Allan Block wall will not be a competition.  Allan Block will cost you less over the 50+ years that they are installed due to time, maintenance, and rebuild.

Next let’s discuss a natural stone type retaining wall.  These can be comprised of limestone, boulders, or other natural rock that is available in your region.  
Natural Stone wall


  • Natural aesthetic


  • One of the most expensive options 
  • Doesn’t install as easy as module block or timber walls
  • May require special equipment due to the size and weight of the material

Since Allan Block has a cost-effective solution and there are so many collections and finishes to Allan Block retaining walls, there will be a better solution using a modular block outside of just the pocket book.

Lastly, if we were to compare a traditional masonry wall, or cast in place retaining wall.  
Cast in Place wall


  • Can be designed for any application
  • Tried and true for hundreds of years


  • Typically the most expensive
  • Non-flexible – will crack in frost or seismic areas
  • Specialized installation – formwork and steel required

A ball park cost savings from a cast in place retaining wall to an Allan Block system can be roughly 50%.  If you don’t like saving money AND having a wall that looks better then cast in place is your route to go!

Allan Block Retaining Wall

Now that we know Allan Block is a cost-effective solution for nearly ALL sites, it really comes down to what collection and color you would like in your backyard.  Feel free to visit allanblock.com to select a store near you or call your local dealer for cost and availability.

Allan Block Retaining Wall

August 23, 2019

AB Courtyard and Swinging Gates Bring Added Security to your Project

Written by Rich Lovdal

 Gates come in many forms from simple wrought iron or ornamental metal gates physically attached to the post/pillar to heavy industrial security gates mounted to their own structural support system. 
Either type can be used our AB Courtyard or AB Fence Posts.  For any gate not physically connected to the post, the fence installer should follow the supplier’s structural post installation procedures.

Today we will focus on how a gate can complement your AB Courtyard project and how to attach a gate to the Courtyard post.  If your project includes a gate attached to the AB Courtyard Post/Pillar, first use the strengthening techniques described in How-To-Sheet #140.  By gluing each course together and using the Concrete column and embedded pile in the center of the post, the individual block units will act as a solid structure to resist the weight of the swinging gate.  

Start your project by knowing the width of your finished gate so that you can build your Post/Pillar the correct distance apart.  If you are using a premade gate it will be difficult to modify if you have built your post too far apart or too close together.

To attach the gate to the post/pillar use the typically provided mounting hinge and commonly used masonry/concrete anchor bolts such as wedge or lag both anchors found at any big box or local hardware store location.  Start by carefully positioning your bottom hinge and making the holes to be drilled.  It is important to place the bottom bracket at the proper height to allow the gate to swing unimpeded.  The anchors you choose will recommend a drill bit diameter.  

Using a standard drill or a hammer drill for easier drilling, drill the holes and mount your lower hinge.  Once the lower hinge is mounted, to determine the exact location on the upper hinge, carefully hang the gate on your lower hinge and brace it in place so that it is in a finished plumb position.   (Plumb – to be vertical so the finished gate will not swing open or close by itself) 

 Once the gate is temporarily in place, position the upper hinge in its final position and mark the holes.  Using the same technique as for the lower hinge, drill the holes and mount the upper hinge and hang your gate.  Using these same techniques you can easily mount the latch hardware on the other post.

For more information on all of Allan Block’s products see our website at allanblock.com or our AB Courtyard How to Sheet #420 - Attaching Gates to Post/Pillar

August 16, 2019

Need your retaining wall to turn a tight radius? We have the solution!

Written by Ryan Miller

With Allan Block retaining wall products, a large sweeping curve or a quick tight one are easy to construct and will leave a great looking finished product.  A curve is the strongest, fastest and most aesthetically pleasing option when a change of direction is required within a retaining wall.  The minimum radius one can build with a full-length (roughly 18 in.) Allan Block unit such as a Classic, Lite or Dover is 4 ft. 

Learn more about installing curves by reviewing our installation recommendations.  If you need to make a tighter radius you may want to consider incorporating one of our units that are ~9 in. in length such as the Jumbo Jr, Bordeaux or Palermo.  These units will allow you to tighten that radius to 2.5 ft – (picture 2 below).  Using these products will allow for a quick installation and a finished product that will meet the aesthetic requirements necessary for your project.  Check out more on our retaining wall products here or give us a call to discuss your project in more detail.

August 9, 2019

How do I find a professional, certified Allan Block contractor?

Written by Souraya Farhat

Now that you have decided on realizing your outdoor living space and have come to the conclusion that building retaining walls, paver patios, patio walls and working with hardscapes in general is not your strongest skill. You will need to rely on a professional contractor with experience and a proven record on the field of hardscapes. 

Before you find a contractor to meet with, you will need to do some research and try to decide on the scope of your project. Online research, visits to local hardscape and landscape shows will help you make selections of products, features and elements that would fit into your project. This will help you classify these selections into needs, wants and would love to have in an effort to determine the scope of the project. Learn more how to prepare for your meeting with the contractors

Now that you have done your homework, you are prepared to meet with a contractor. However, where to find them and how to hire the right one is another important step to ensuring the success of your project. Here are some resources to find contractors:

The last thing you need is to deal with a failing wall, improper water drainage and many other issues that can result from a bad installation. Relying on professionals that are skilled, trained and have obtained manufacturer’s certification may beef up the price, but it is a small price to pay for a peace of mind.