[Lamantino]

Hi!

We have a 4' tall retaining wall in our yard that holds back the neighbor's soil which is at higher level than our yard.
Recently, we have lowered the grade on our yard to make it one uniform level across most of the yard, but we left some dirt against the retaining wall to support it.
We are planning to build a short (maybe 2 feet) retaining wall to keep that dirt in place, but wanted to keep about 5 feet gap against the existing wall to place a BBQ.

The question we have is how to add support to the existing retaining wall in the gap area where the BBQ will be placed?

Any help would be appreciated!

 

[Nealtw]

Modify the BarB Que to sit on the wall, a mistake here would be costly.

 

[huesmann]

I don't suppose you know how the wall foundation is constructed? Typically you need a certain amount of earth in front of the wall.

 

[Lamantino]

The wall has a 4.5" concrete footing (as can be seen in the picture). Otherwise, I don't know how it's constructed. I was wondering about digging underneath the "gap area" and somehow filling down with concrete. Any thoughts on that?

 

[Nealtw]

The wall has a 4.5" concrete footing (as can be seen in the picture). Otherwise, I don't know how it's constructed. I was wondering about digging underneath the "gap area" and somehow filling down with concrete. Any thoughts on that?

When we build a retaining wall it will have a 10 or 12" footing and maybe 3 ft wide mostly under the high side.
Retaining walls usually are put in by the guy with the higher property. I would say that that wall is less than it should be so if you want to underpin it you also may want to add braces of some sort while you do the work under it.

 

[3onthetree]

Ditto on the advice the BBQ should be separate either away from or on top of the wall, the new wall should be continuous.

The existing wall's height, soil type/water content, construction (footing width, tiebacks etc) would help you determine how to build the new terraced layout. Realistically though you probably can't come up with that detailed information. So as a minimum, with the new wall being only 2 or 3 courses high, if you keep the distance away from the old wall at least 2X the height of the new wall that should prevent you from having to hold the upper wall's surcharge with this lower wall. Water drainage behind your new wall is critical, as it looks like the well drained existing wall (CMU weeps at 16"o.c. + the stone joints) is what is keeping it held up.

 

[Lamantino]

Thanks for the advice! It sounds like having that gap for the BBQ is complicated and can affect the integrity of the wall. I am thus starting to think of having the wall continuous and somehow placing the BBQ with its profane tank above it. Any ideas there?

For the wall itself, the thought is to go with a dry stack stone retaining wall. Any suggestions on the structure of the wall and in particular on its drainage?

 

[3onthetree]

profane tank

LOL autocorrect is amusing sometimes. I chuckled picturing the mason jar where you have to put a buck every time you say the F word in front of the kids.
Is there any other place for the BBQ? I can get some greasy bonfires goin on mine, you are right against the wood fence and is that vinyl lattice?
I would build the wall starting with basic standards, min 6" gravel base, drain tile to daylight behind, gravel drainage plane behind protected by textile.

 

[Lamantino]

There's other options for placing the BBQ in the yard, but that area kinda fit well with a plan for a patio in that are. Also, the yard is not too big, so pushing the BBQ against the fence feels natural in terms of utilizing the space.

Yes, there use to be an old wood fence in front of that wall that covered the vinyl lattice. Once that old wood fence was removed, that ugly wall on the right was reveled.

For the wall structure, did you mean installing a perforated pipe? Could I get by with gravel only? The rocks will have gaps assuming it's dry stack wall, so I would think the water can find its way throughout the wall. Also, in general, I think the rocks are laid against the tilted soil in a dry stack wall so to use gravitation for holding the rocks in place. I am just not sure how that plays out with having gravel behind the wall.