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.