log retaining wall behind round pen

[bigballer]

wanted to get some opinions on the idea i had the other day. i need to build a ~30" retaining wall on the high side of my round pen and have considered quarry rock and the anchor pre-cast blocks but wanting to keep costs down i started brainstorming. i am cutting down many alder trees and figured if there was a possibility of using these for my wall, i could save myself quite a bit of money and it would be kind of neat to have a wall made from something on my property. my plan is standard retaining wall process - fabric, perf pipe, clean stone, etc. i know long term that rock or pre-cast blocks will outlast the alder by several years but given this idea, how long could i really expect the logs to last? should i treat them with something? these are all strong standing trees from 6"-10" in diameter. obviously the question of securing them has come up so i came up with a concept of how i would do this. attached are a few pictures. the wall would be curved and i would cut 6" out the ends of each log (8ft) so two would lay together and i would secure them with 10" galvanized spikes on each end as well as 1 or 2 spikes along the middle. i would use a staggared build like shown in the pic's - anyone have any comments on this idea?

 

[jinman]

I don't think your untreated logs will last much longer than two or three years. You just cannot get the alder treated well enough to do the job for anything more than a short time. By cutting the logs, you only encourage more decay by removing the protective bark. If your wall was cedar, it would last much longer. I think the alder is going to be easy to work, but it is not suitable for outdoor use. Your idea is very creative, but your choice of building material needs to be different.

 

[Slacker]

Here is a bad pic of the method I've used several times in the past.
PT 4x4 with cedar uprights. It's been working like a charm for 3 years now.
Used the PHD to set the cedar logs. Used galvanized 6" screws to screw every other 4x4 together.

 

[EddieWalker]

I don't think your untreated logs will last much longer than two or three years. You just cannot get the alder treated well enough to do the job for anything more than a short time. By cutting the logs, you only encourage more decay by removing the protective bark. If your wall was cedar, it would last much longer. I think the alder is going to be easy to work, but it is not suitable for outdoor use. Your idea is very creative, but your choice of building material needs to be different.

I agree with Jim 100%.

In just a year, you'll see some level of decay. The question is how many years will it get to the point that it falls apart? My guess is 5 years.

Eddie

 

[bigballer]

thanks for the replies, i figured around 5 years tops for the wall to "stay intact".. a local lumber store sells recycled railroad ties - aside from the environmental issues, i'm guessing these would last quite a bit longer then the alder. i do have cedar as well but not enough "cutable" for the size of the wall i need and they are around 30" diameter.

any other "creative" methods people have used to successfully build a retaining wall?

 

[jinman]

any other "creative" methods people have used to successfully build a retaining wall?

I have a sawmill just about 5 miles from my house that cuts old telephone poles into 6x6 timbers. They vary from 10' to 15' in length and they do have some short stubs. You might check in your area for something like that. The poles are not nearly as heavily creosoted as crossties. I built a 40' retaining wall with them and they stacked beautifully together. You could cut and notch them for your round retainer and they would look good. They do have some creosote odor though. That goes away after about a year of being exposed to the weather. for your purposes, you might just buy the uncut poles and cut them into sections like your alder logs.

 

[rdbrumfield]

Hello neighbor,
montesano

Won't repeat jinman, had the same idea

 

[denmansoft]

I have 8 acres of the same alder. Within a year of it coming down it is in no shape to consider for construction. Maybe for forms/bracing on the short term.
It burns Ok in the fireplace...

 

[Tom_H]

Jim said it as well as could be said.

 

[PitbullMidwest]

... a local lumber store sells recycled railroad ties - aside from the environmental issues, i'm guessing these would last quite a bit longer then the alder.

I live in a railroad town where there is no shortage of used ties or retaining walls made from them. A wall made from ties will last 20 years minimum if constructed properly. My church just replaced a RR tie wall in our lower parking lot that was 25 years old. We paid $5 a tie to replace it.

As far as environmental issues, the creosote doesn't leach from the ties and poses no greater risk to the environment than pressure treat.

The down side is they are not attractive especially once they start to age.

 

[AD18]

I assume that since you have alder and cedar you're on the west side of the Cascades too. My experience with alder will be simular to what you will be dealing with, i.e. If it is in contact with the soil you will see the bottom log rot within a year. Fungus will sprout and the bugs move in. If used for fence rails, mounted on pt posts, treated with preservative after the bark peels you can expect to get several years of service. My nieghbor has this setup around his garden to keep the deer and elk out. Any river rock in your area? Good luck with whatever design you choose.

 

[bigballer]

thanks for all the replies and ideas - yep i'm on the west side of the cascades 40 miles west of stevens pass on hwy 2 right in the middle of alder/ceder/fir/hemlock country. i don't have access to affordable river rock but i do have a local quarry that sells 1/2 man cut basalt at a decent price ($26/ton) so i've decided to go that route. i'll need about 10 ton for the 100sqft face which will mean alot of trips to the quarry but building out of rock means no need to worry about replacing in 5-10-20 years so once it's done, it's done.

thanks again for the input - i figured i saved myself alot of future headache by using this great resource of experienced folks!

 

[EddieWalker]

Building with rock sounds like an awesome idea. Like you said, it will last forever, but it will also add value to your place!!!!

Post some pictures when you start it, rock walls are always allot of fun to see being built.

Eddie

 

[bigballer]

yes eddie, i too believe the rock walls are a thing of beauty and stand the test of time. a couple years ago i built a similar wall to protect my barn but used large 1 man rocks.

well here is the beginning stages - the wall is cut back and the trench is dug for the perfpipe which will drain into the swale. i have a load of washed 1-1/4" being delivered this morning so a few trips to the quarry should get me started - will post more pics as things progress - not much to look at right now..

 

[bigballer]

update on the progress of this wall, it's mostly completed now, 7 ton of rock and about 5 yards of 1 1/4 washed rock behind it.. i didn't have time to get my backhoe on the tractor this weekend so i still need to finish extending the outlets to the swale. we had a good soaker last weekend and it was pushing water out both ends of the pipe so looks like it's going to do the trick..

 

[RedDirt]

That's a beautiful wall you are building. I like the curve and the battered face. The curve and angle compliment each other nicely. This was a much better choice than the alder logs! It will be appreciated for decades, long after several alder walls would have rotted.

For others doing such projects and using corrugated perf pipes. Take care to grade your bedding layer of gravel as close to flat as possible. Forensic engineers here have found a large number of failures due to dips in the pipe. This aspect is of much less concern for a dry laid rock wall like bigballer's but becomes critical in an impermeable wall installation. Most civil engineers I have dealt with in the past ten years have ceased specifying corrugated perf all together and have gone back to rigid perf or slotted pipes. In critical areas like basement foundations it is also a good practice to place a layer of filter fabric between the earth cut and the gravel. We normally run the gravel up to 18"-24" below grade, run the filter fabric over the top of the gravel, then compact a moisture conditioned soil cap above the gravel. The higher the clay content of the cap the better. The fabric keeps the gravel clean and the cap keeps the subdrain system from being over charged with surface runoff which should be led away from the building at at least 1/4in/ft.

For corrugated perf I'd use a tool similar to a long concrete float but hinged longitudinally to flatten the bed before pipe installation.

Another practice that that used to be common and is now frowned upon is the wrapping the perf pipe itself in filter fabric. We used to call these "Burritos". These drains have a high rate of failure due to the fines clogging the perf holes relatively quickly.

 

[EddieWalker]

bigballer,

Thanks for the update. Your wall looks amazing and I'm sure you've increased the value of your land tremendously!!! Definately a project to be proud of.

RedDirt,

Thank you for the information. What you say makes allot of sense, but it's stuff I hadn't considered or thought about. If you only do a few or less walls a year, it's not something that I keep up on.

Would similar advice would apply to french drains? Solid pipe and no burrito wraps?

Eddie

 

[RedDirt]

bigballer,

Thanks for the update. Your wall looks amazing and I'm sure you've increased the value of your land tremendously!!! Definately a project to be proud of.

RedDirt,

Thank you for the information. What you say makes allot of sense, but it's stuff I hadn't considered or thought about. If you only do a few or less walls a year, it's not something that I keep up on.

Would similar advice would apply to french drains? Solid pipe and no burrito wraps?

Eddie

Eddie,
French drains should get the same attention as retaining wall and foundation drains for the best results. But a french drain failure rarely carries the same implications as a leak directly into the basement from built up hydrostatic pressure and a clogged foundation drain. None-the-less, rigid pipe is better than flex pipe if you can spring for the extra bucks. If you still want to use flex, fine, just pay special attention to preparing the bed flat. And I wouldn't use a burrito wrap on ANY perf drain pipe anymore.