Re-Enforce Wood Retaining Wall

[Rtmurray]

I have an existing retaining wall that's 50' long and 3' high. The wall is made of 4x6 creosote wood and a deck sits on the sloping dirt it's supporting.
Over the 11 years I've had my house the wall has bowed a little bit...nothing really significant but you can tell it leans a little. I would like to reinforce
the wall with big 17"x10" inch cement blocks from Home Depot. Each one of these blocks weigh 65lbs. If were to erect the brick wall in front of the existing
wall would this be enough support? If so, there would be a little gap between the bottom and top since the existing wall leans at tad. Would I fill this in
with gravel as I make my way up?

Thanks for any help you can provide.

 

[hokie66]

I would take the wood out as you build the new wall. And build the new wall leaning back into the fill, so that any future lean will not be past vertical.

 

[oldestguy]

I'm, assuming you are using these stones laid in a bonded pattern, like brick. Prior wall of lighter and less depth has held, sort of. With a non-level upper earth surface adding more load than a level surface, these factors put together would tell me that a leaning back gravity wall will be OK. A gravity wall is an intact wall made up of brick, stone, or other heavy material, with the depth from outside to back of one third the height, and leaning some would be OK. You don't quite meet that 1/3rd H, but your prior wall probably was more of an erosion preventing thing or the earth itself had plenty of cohesion to keep it there. In three feet height, with top maybe 5 inches back it should be fine. You can get that by setting each course back a little from those below, rather than tipping the blocks, so then the top surface is level. Just replace the old, working along the wall length.

 

[hokie66]

I find it simpler to tip all the blocks back, and you can control the lean with just a short spirit level. Most of these type walls have a lug at the back to prevent sliding of the individual courses, so offsetting them doesn't work. There are a few types of these gravity walls, but I have built some myself, and that is what works for me. Filling any gap with granular material is the way to go. If you are concerned about staining on the front face, use a geotextile fabric over the existing cut face.