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Old 11-06-2015, 12:23 PM   #1
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Deadman - Yes/No?


Hi, I plan to terrace my backyard. Each terrace would be 2 feet tall x 30 ft. I plan to place 6"x6" 8ft lumber in the dirt staked by 2ft 3/8" rebar at each end. And on top of that staggered 6"x6" 8ft lumber, each layer(4 layers) connect to the one below with 8" wood screws. Is this OK? Thanks
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Old 11-06-2015, 01:36 PM   #2
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Quote:
Originally Posted by funkstar View Post
Hi, I plan to terrace my backyard. Each terrace would be 2 feet tall x 30 ft. I plan to place 6"x6" 8ft lumber in the dirt staked by 2ft 3/8" rebar at each end. And on top of that staggered 6"x6" 8ft lumber, each layer(4 layers) connect to the one below with 8" wood screws. Is this OK? Thanks
If you live inside a city limits, you need to ask them on their rules. If in the county, go ask your county.

If you got heavy rains, those rebar are not going to hold anything up. The wood will also rot over time.



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Old 11-06-2015, 01:38 PM   #3
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I am not sure what you mean by OK. Unless it is ground contact rated pressure treated lumber, your wall will begin to rot quickly, and could disintegrate in less than ten years. For terraced walls, I suggest looking into concrete segmental block. There is an entire industry devoted to making them, companies like Allan Block, Versa-Lok, and dozens of others make various sizes and styles of concrete block designed to interlock and for a two foot high wall, require no soil reinforcing. I built a 4 foot high wall in my backyard, about 40 feet of wall, worked out very nicely. Cost effective, lasts essentially forever, zero maintenance.
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Old 11-06-2015, 03:13 PM   #4
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Originally Posted by gregzoll View Post
If you live inside a city limits, you need to ask them on their rules. If in the county, go ask your county.

If you got heavy rains, those rebar are not going to hold anything up. The wood will also rot over time.
I got the idea of using rebar here:

I live in the city but I figured the less bureaucracy involved the better.

Quote:
Originally Posted by Daniel Holzman View Post
I am not sure what you mean by OK. Unless it is ground contact rated pressure treated lumber, your wall will begin to rot quickly, and could disintegrate in less than ten years. For terraced walls, I suggest looking into concrete segmental block. There is an entire industry devoted to making them, companies like Allan Block, Versa-Lok, and dozens of others make various sizes and styles of concrete block designed to interlock and for a two foot high wall, require no soil reinforcing. I built a 4 foot high wall in my backyard, about 40 feet of wall, worked out very nicely. Cost effective, lasts essentially forever, zero maintenance.
I plan to use pressure treated lumber. I was told/read it should last 20+ years.
I think stone involves too much labor.

I was going to build something like:
http://www.fairfaxcounty.gov/dpwes/p...ll/details.pdf

https://books.google.com/books?id=af...caping&f=false
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Old 11-06-2015, 03:41 PM   #5
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Concrete segmental block is not stone, it is concrete. The blocks typically weigh anywhere from 40 - 100 lbs, depends on size. Different manufacturers make different sizes. I used Ideal blocks, they weigh about 50 lbs each. As to labor, based on my personal experience, there is not a lot of labor involved in setting the block, you prepare the level base (no concrete required, just a flat surface with a little crushed stone), then you start stacking blocks. After the blocks are installed for a row, you backfill with soil that drains well (sand or gravel works nicely).

Similar amount of labor required to build a wooden wall, maybe more, since you have to drive the rebar or spikes to retain the wood. But the real reason for using concrete is that it does not rot. I am not sure who told you that ordinary PT lumber would last 20 years in ground contact. There is an enormous range of opinion on this topic, just google it and see for yourself.

The best answer seems to be that the longevity of PT lumber in the ground depends on the type and quality of pressure treatment, how aggressive the soil microbes are, and how moist the environment is. There are wooden walls in my area that are rotting after less than 20 years, I don't know if they are PT or something else. Then there are those who claim that PT lumber will last upwards of 50 years. Maybe you can come back on this forum in 20 years and let us know how the wood worked out.
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Old 11-06-2015, 09:43 PM   #6
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ATOH is the first place to find ideas. The guy in that video, is all about return business. He is going to make it, so that he has to come back when there are bad rain wash out, the wall starts shifting, so that he can keep making money off of them.

If you look, they have the old Rock wall back there behind the Ivy. Which I would keep and not put up those stupid timbers.

If a rock wall is installed correctly from the beginning. Minor maintenance through out its life. It will last Decades, over the timbers.



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Old 11-06-2015, 10:11 PM   #7
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I built timber retaining walls while in college, some over 5 ft high, that are still standing proud 25+ years later. You need to make sure there is a good stone base and good drainage in general. We back filled with lot sand and top dressed with topsoil for plantings. If your soil is high in organics and moist I'd maybe think of doing something else because PT *will* rot if left in damp conditions for long periods.

We used to use 1' sections of rebar to pin the courses together instead of using wood screws. You definitely need deadmen. Right angles and box corners make the wall very stable and strong. You pretty much have to think of it as two walls tied together - one you can see and the other one that is buried to anchor it.

The concrete block systems that are available now are much less labor intensive in construction as well as maintenance. If a timber wall gets damaged, you pretty much have to dig it all out and rebuild it, then rebury it. The block systems lock to the course below, so fixing/replacing is pretty simple.
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Old 11-06-2015, 10:20 PM   #8
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I've built small retaining walls that way, under 3'. Better to use longer rebar, as long as you can pound into the ground, 6-8', and run them through two or three of the timbers. You can buy long extensions for spade bits.
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Old 11-07-2015, 01:58 AM   #9
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For some reason the first part was supposed to state "ATOH is not the first place to find ideas." You have to take into consideration of the soil where the wall may be built.

Yes Wood Foundations are built in various areas of the country and stand up to 50 years or more, if taken care of.

Without pictures of where the OP plans on putting in this wall, what neighbors are using. I can say first hand in my part of Central IL, that these type of walls, do not last more then 10 years with the type of Winters that we have.

This is actually my mom's Parents old house. The Terrace wall was actually in better shape when my grandfather was alive and it was a set of three wall sections. The one in front of the house to the left has been there as long as my grandparents had lived in that house.

It has actually seen better days. But with over 30 years of not being maintained, you can see what happens when decades of Winter and heavy rains take over. We actually used to climb up and down that wall during the Summer to pull weeds as kids. It is probably close to 100 years old, same as their old house.

It is just an example to the OP, that if they are going to build a proper wall. Make sure that it will be maintained with minimal effort. Especially once the earth starts moving within the terraces. That would mean putting in a multi-level drainage system, to allow any ground water that may soak into the sections, to be able to exit at the bottom and middle levels.

As for in the city. You are never going to get around Red Tape. Terrace Walls are also for some Home Owner's Insurance companies, a possible liability issue, if they have metrics of people getting injured on them in the area that they look at, to adjust your rates.

https://www.google.com/maps/@40.6586...7i13312!8i6656



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