Do I Need To Glue My Retaining Wall Blocks

landscaper building a retaining wall out of gray blocks and glue

So you’ve decided to build a retaining wall in your yard.  That’s great news.  You’ll undoubtedly enjoy the finished product and how it allows you to solve your grade change in an aesthetically pleasing manner.  However, in the meantime there are likely some questions you are asking yourself.  Like how tall can you build the wall without using geogrid, and how much crushed stone do you need under the first course?  Also, do I need to glue my retaining wall blocks?  We’ll review the answers to these questions in the following paragraphs.

Retaining Wall Regulations

Like any project you’re attempting, the first thing to consider is regulations. Check with your local, county and state to determine if there’s any permitting required for your wall.  If you’re not sure, go ahead and call the local building department and talk it through.  Typically there will be two classifications of walls, or maybe more.  

First there is a retaining wall.  This is a wall that’ll need to be permitted and you may need an engineers stamp on the wall design.  Then there is a ‘planter wall’ or ‘garden wall’ which is not considered structural.  These walls may be identical in construction, with the only difference being the height. Usually there will be a cut off at 2’, 3’ or 4’ as to what they consider a ‘retaining’ wall versus a ‘garden’ wall.

Do I Need To Use Geogrid My Retaining Wall Blocks?

For the most part, if you’re building a short wall you won’t need to use geo-grid.  However, check with the manufacturer of the wall system, and find out what they recommend.  Even though you may not need to bring in an outside engineer to stamp the structural design, it’s important to follow the manufacturer’s design to make sure the wall is built to last.  

The manufacturer’s literature is also the best place to start when it comes to determining how much crushed stone to place under the wall.  You may want to embed a perforated drain pipe under the wall also depending on site conditions.  Perhaps you live in an area where frost is a concern. In that case, digging deeper and building back up with crushed stone is important.  

Compacted crushed stone will give you a solid base to build your retaining wall or garden wall upon, and if it’s deep enough, the ground will not shift when it freezes and move your wall.  Four feet is usually enough, but in some areas up north deeper is required.

large retaining wall with green shrubs nearby and glue on top showing do i need to glue my retaining wall blocks as yes

Do I Need To Glue My Retaining Wall Blocks?

This brings us to the last question, do I need to glue my retaining wall blocks?  The answer here is once again manufacturer dependent.  However, you can always use construction adhesive when putting a block wall together.  Nearly every builder will at least use adhesive when placing the wall cap on. This is because there isn’t much holding it in place otherwise other than the weight of the wall cap itself.  Whether you glue the other courses is not all that important unless the manufacturer specifies otherwise.

When asking do I need to glue my retaining wall blocks, you ought to keep in mind if there’s any frost heaving or expansive soils issues behind the wall, glue isn’t going to help.  The glue is more to help hold the wall blocks in place during construction. Except, it should be used for the top course or two which don’t have the advantage of the weight of the wall itself holding it in place.  The last thing you want is for someone to walk up to your wall, and pull off the top block without meaning to.  

Do I Need To Glue My Retaining Wall Blocks Summary

To sum up, in our opinion the answer to do I need to glue my retaining wall blocks is yes, but only the top couple of courses at most.  If you want to glue them all or the manufacturer tells you to, then by all means go right ahead.  It certainly can’t hurt anything.