Tag: landscape designer virginia

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Why Is This Retaining Wall Failing?

I walk by this wall whenever I walk to the post office in downtown Culpeper. Walls like this are pretty common in older neighborhoods like mine. Leaning and generally unhappy walls are, sadly, pretty common as well. So what gives? Why do these walls look like they’re ready to flop over on the sidewalk?

There are several possible explanations. The first is insufficient footer, or failure to tie the wall in with the footer. When building a masonry retaining wall in Virginia you generally want to dig down 24″ below grade, so you’re below the frost line. You then pour a beefy footer (thickness varies depending on application), often with rebar coming up from the footer to tie the wall to the footer. Our home was built in 1906 and renovated in the 1950s, and I can tell you with certainty that there was not a lot of digging to frost depth being done way back then.

Another possibility is insufficient drainage behind the wall. Water is a wall’s worst enemy. Hydrostatic pressure is a major cause of wall failure. The way we avoid a buildup of pressure is by using a “drainage chimney” of clean gravel behind the wall, along with periodic weep holes.

What makes this wall great for illustrative purposes is the fact that the wall likely started to fail because of hydrostatic pressure (water buildup behind the wall). This pushed the top of the wall forward, creating a gap between the wall and the slab. What’s right above the slab? Downspouts! So not only do we have a gap, we’re pouring gallons upon gallons of water behind the wall with every storm. Awesome.

So how would I fix this wall? I think we’re beyond the point of fixing something like this, and it needs to come out. Improper construction is hard to correct, and when it gets this bad – there’s no Band-Aid big enough.

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Elements of Design: Shape or Form

We often think of shapes as two-dimensional: squares, rectangles, circles, and triangles. This isn’t how we perceive them in the landscape, however. We see them in three dimensions, like cubes, spheres, and cones. Shape (or form) in the landscape can even dictate how a space feels.

This is a backyard I did for a client in Phoenix, Arizona (sorry, pygmy date palms aren’t going to work in your McLean landscape design). As you can see the shapes are all sinuous curves with nary a straight line in sight. This gives the yard a much more casual, relaxed feel.

Here, you see a lot more angularity of design. This house is a very dominating, simple, rectangular shape, so it made sense to carry those lines all the way to the street. In so doing, you can see we also used the principle of unity (part of harmony). It all ties together!

Part of the reason that I think it’s important to discuss shape in the landscape is that I see a lot of folks forgetting that the shape of their home is a dominant part of the design. Everyone wants flowing curves on everything. Well, I wish I could wear a paisley suit jacket, but I’ll never be able to rock that look. Such is life.

Unless your home was designed by Frank Gehry (or you live in an igloo), your home is a box. Or it’s a grouping of a few boxes. Regardless, the dominant form is rectilinear. That doesn’t mean that you’re limited to a simple rectangular patio, for example.

In the photo above, the house is a massive, two and a half story brick edifice. The client initially wanted big sweeping curves on the patio. I tried, but nothing worked. It was as wrong as sticking a trucker cap on the Queen of England’s head. So, we did a stepped edge on the patio to break up the profile and allowed all the plant beds to swoop and curve and blend the landscape design into the woods. The design finally worked, and what’s even better – the client loves it.

Shape’s fun to play with. It’s one of my favorite parts of landscape design.

Next up: Mass!