Boobs McGee

06-23-2011, 10:13 PM

Designing a retaining wall for some friends, and was hoping for a little advice.

Basically, they want a 3-4' wall around three sides of a sandbox...kind of like this

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l l

l l

l l

l l

l l

It's going to be constructed using treated 6x6's (personally, I don't know if they've made safety progressions in the treated lumber world, so I'm not sure if it's safe for kids in terms of splinters and whatnot, so if anyone has any idea feel free to chime in).

My BIG question is, how many deadman am I going to need in the back wall? (the "solid line" in my "illustration" haha) It's going to be 4' tall, and it's holding back some good ol' fashioned colorado soil...which here in the front range, has a LOT of clay. Anywho, I've heard that after your first course of timber, a sensible amount of deadman are: every third row, and 8 foot of spacing. Since the back wall is about 15 feet long, and 4 feet tall, I'm thinking a total of 4 deadman? 2 on the third row, and two on the second to top row?

The hill doesn't have a very steep grade, maybe 5 or 6 degrees?

Does anyone know if 4 of those will be overkill? And also, should they be staggered, or can they be vertically aligned?

Lastly, the side walls are going to gradually build from the first course up to the top...so I was thinking one deadman per side at about the 3' mark.

Cheers and thanks!

Oh, and the walls are about 10 ft long.

Basically, they want a 3-4' wall around three sides of a sandbox...kind of like this

_____________________

l l

l l

l l

l l

l l

It's going to be constructed using treated 6x6's (personally, I don't know if they've made safety progressions in the treated lumber world, so I'm not sure if it's safe for kids in terms of splinters and whatnot, so if anyone has any idea feel free to chime in).

My BIG question is, how many deadman am I going to need in the back wall? (the "solid line" in my "illustration" haha) It's going to be 4' tall, and it's holding back some good ol' fashioned colorado soil...which here in the front range, has a LOT of clay. Anywho, I've heard that after your first course of timber, a sensible amount of deadman are: every third row, and 8 foot of spacing. Since the back wall is about 15 feet long, and 4 feet tall, I'm thinking a total of 4 deadman? 2 on the third row, and two on the second to top row?

The hill doesn't have a very steep grade, maybe 5 or 6 degrees?

Does anyone know if 4 of those will be overkill? And also, should they be staggered, or can they be vertically aligned?

Lastly, the side walls are going to gradually build from the first course up to the top...so I was thinking one deadman per side at about the 3' mark.

Cheers and thanks!

Oh, and the walls are about 10 ft long.