Does A 2 Foot Retaining Wall Need Drainage?

Retaining wall in shade of backyard with pergola in background

In the backyard it is common to solve minor grade changes with what many call seat walls.  These are retaining walls which are one and a half to two feet tall.  Often there will be planting behind them and sometimes they’ll even be a part of the seating around a fire pit.  These overflow seating areas can be a great addition to any backyard and they can solve the sloping grade in your yard all at the same time.  When building these retaining walls do you need to consider any of the features of larger retaining walls?  Does a 2 foot retaining wall need drainage?

Does A 2 Foot Retaining Wall Need Drainage?

Like many features in the backyard, the answer to this question is that it depends on a few factors.  Drainage is often an overlooked feature. This is especially common when contractors are ‘bidding’ against one another.  After all, you don’t see the drainage. Furthermore, if the drainage is working properly, you never even think about its existence in the first place. 

How Much Does Adding Drainage To A 2 Foot Retaining Wall Cost?

Adding drainage to your 2’ retaining wall may cost an additional few thousand dollars. However, in the grand scheme of things, it’s probably worth it.  If you were building the wall yourself, it’s something you’d do to protect your hard work.  It’s unfortunate, but in many cases, contractors will ignore the need for drainage. This allows them to simply save a few dollars so they make sure to outbid the competition.

Backyard Answer To Does A 2 Foot Retaining Wall Need Drainage?

Location, Location, Location

The major consideration of whether or not you need drainage will depend first on where in the country you live.  If you live in a dry climate state like most of Arizona, Nevada, New Mexico, or West Texas, the answer is likely no.  But even there it’s not a bad idea to integrate a minimum of drainage protection. This is a great way to insure your investment against heavy rains which, though rare, do occur.

In wet climates and climates with frost damage potential, it’s always a good idea to integrate a drainage system into your wall construction.  It can be as simple as digging a trench under the wall footing and installing a bed of crushed stone underneath the wall to facilitate drainage.  If you want to do it ‘right’, integrate a perforated drain pipe in the stone bed behind the wall down at or below the footing level.  

To drain properly you always need to remember how gravity works.  If you dig a trench, fill it with crushed stone, and the bottom of the trench is the lowest point in the stone bed, the water will just sit in the trench like a dry well.  This can be disastrous in a freezing climate.  Always make sure your stone bed drains to daylight.  That is the bottom of the excavated trench continues to a place where it seeps out onto the surface.  

Does A 2 Foot Retaining Wall Need Drainage Explained

Flat Yard Drainage Alternatives

If you have a flat yard and draining to daylight isn’t possible, a dry well might be a good solution.  A dry well is usually built using a precast concrete or plastic container filled with large rocks. You then pipe your drainage water to the dry well.  This creates a place for the water to pool and slowly percolate into the ground.  Depending on your soil type this may be a good solution.  

If you have a low spot on your property but it’s far away from where you are building the wall you will want to pipe the water to the low spot.  To do this you can connect a pipe to the perforated pipe in the trench and run it to the low spot on the property. 

Does A 2 Foot Retaining Wall Need Drainage Summary

Ultimately, the goal is to get rid of the water in and around the retaining wall.  This prevents damage, seepage, and in general any changes to the wall other than natural aging.  Does a 2 foot retaining wall need drainage?  In our opinion, yes.  But ultimately, it is up to you.  Hopefully this has helped you consider some ways of accomplishing it if you choose to incorporate drainage into your backyard retaining wall project.