# Forum Home Renovation Retaining Walls  Any limit to height of sleeper retaining walls?

## Ashwood

Hi, 
Just wondering if there is any height limit to using timber sleeper retaining walls? 
I need to put up a retaining wall of possibly up to between 1.3 & 1.5 m height.
Using steel H section posts embedded in concrete, and 200 x 75 red gum sleepers. 
Any issues with these?  Do I need to go deeper (800 mm deep?) or use shorter lengths eg. 1.8 m sleepers hence more posts? 
Views appreciated.  
Ash

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## Terrian

what is out should be in. 
if the wall is 1.5m high, you should be going 1.5m deep, chances are you are going to need a permit for over 1m high

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## Bleedin Thumb

There sure is. Besides the engineering aspect of it, its governed by your local councils reg's. At a guess I would say no engineer would certify a sleeper wall over 1.3m if for no other reason than the expected life span of timber.  
As far as the depth goes I'm less conservative than Terrian I use  - over 1/2 as depth but if its low I use closer to equal.

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## autogenous

Based on the life span of the timber and the work that you will be putting into wall eg: excavation I would do it in masonry unless you really really like the appeal of the timber. 
The amount of people looking at ripping out sleeper retainers is amazing. 
Its not the material that costs the money it is a lot of the time the excavation and the replacing of paving.

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## Ashwood

Hi all,  
Thanks for the input.  
I will be submitting to the Council. 
The thinking behind considering sleepers is cost & speed/ease of construction.
Concrete walls or retaining wall blocks cost quite a bob, and are more difficult & slow to construct. 
Another option is using the H sections and concrete sleepers, but the cost of the sleepers themselves are 3x the cost of the red gum ones. And much heavier to handle.  
I'm now rethinking re Autogenous' comment about lifespan - don't like the idea of redoing them later. No repaving needed here, but will involve digging back, replanting & returfing. 
Autogenous, when you say masonry, do you mean bricks, plain blocks (how much roughly eg. per sq m run or other measurement?) or the nicer looking retaining wall blocks (which are quite costly).  
Ash

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## SLUGGO33X

Check to see if your local bessa block supplier has any seconds for sale. I picked up 3 pallets of seconds from Boral in Sydney for a fraction of the new price and to be honest, the blocks look like firsts.

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## Dan574

I would get a price on one of these products,  http://www.boral.com.au/masonry/reta...tractorBuilder 
Not sure of the price but for ease of construction and time I reckon they would on par.  They would last longer and look better IMO.

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## Ashwood

Just did a quick quantity count and phonecalls to get a price estimate. 
The concrete sleepers would cost about $3,000 while the Boral Keystone ones would be about $4,500. Not including ancillary costs such as concrete, etc, and of course labour.  
I agree they look nicer imo as well, but I'll probably get someone to do it, and the labour cost would probably be a fair bit more than the sleepers as well, so doesn't look promising budget wise. 
A bit more searching to do ... maybe the Besser blocks, if not, then the concrete sleepers look more the go.

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## Terrian

> Just did a quick quantity count and phonecalls to get a price estimate. 
> The concrete sleepers would cost about $3,000 while the Boral Keystone ones would be about $4,500. Not including ancillary costs such as concrete, etc, and of course labour.  
> I agree they look nicer imo as well, but I'll probably get someone to do it, and the labour cost would probably be a fair bit more than the sleepers as well, so doesn't look promising budget wise. 
> A bit more searching to do ... maybe the Besser blocks, if not, then the concrete sleepers look more the go.

  blah, just make it a concrete wall, we did  :Smilie:

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## Ashwood

Hi Terrian, 
Concrete wall - i had the impression that is THE most expensive option of all.
Structural engineer design, L footing hence need to excavate backwards into the higher area, rebars, formwork, and costly concrete. 
(For me it's far inside the backyard so need concrete pump & hose run as well).  
How much roughly did yours work out to all in, per m run and what height? 
Ta,
Ash

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## Eastie

Sleeper walls fail due to design, as do block walls. Inappropriate or non-existant drainage, lack of decent footings, inappropriate selection of timber/cheap timber are all "build to fail" scenarios.  As said above at or above 1000mm in height you technically need a building permit which will require you to have an engineering diesgn. 
If you use treated pine look around and work out where the builders/council are getting their outdoor timber and go there (it wont be bunnies!). Places like Lewis Timbers and Col Smith garden and building supplies are what you should look for if going down the timber path. They source suitably graded and treated timbers. 
Why I say this is builders have to warranty their work and products they use, and like any decent tradesman they don't want their work to fail so they tend to stick with suppliers of quality products. Theres no reason why a well designed and constructed sleeper retaining wall with gal steel posts and class 1 durability or H4 timber won't still be structuraly sound and standing in 40+ years time. 
My pref for what you're doing is 3-3.2m sleepers cut down to 1.5-1.6m length with hot dip gal posts at centres to suit so long as you incorporate suitable drainage.

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## pawnhead

I'm just wondering; couldn't you taper the ground at the bottom up 250mm, and up another 250mm from the top of the wall? That would bring a 1500 retainer down to 1000. Of course it would also eat up another 500mm of land if the batter was at 45 degrees. Is there a maximum amount of natural grading that you can go to with filled land, or are there any other problems with this suggestion? 
Reason I ask is that I've got a driveway out front that's very tight for two cars and I'd like to widen it. There's a rubble retaining wall about 1200 high that's falling apart at the moment. I'd like to pull it down and pinch a bit more room for the driveway, but then it would have to be even higher so I'd like to just taper the ground up from the top, to bring the wall height down a bit so it doesn't fall apart like the old one. I'm going to do it anyway, but I'm just wondering if the council would have to be involved if the finished wall was only 1000mm high with a fairly steep batter up from the top.

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## Ashwood

> I'm just wondering; couldn't you taper the ground at the bottom up 250mm, and up another 250mm from the top of the wall? That would bring a 1500 retainer down to 1000. Of course it would also eat up another 500mm of land if the batter was at 45 degrees. Is there a maximum amount of natural grading that you can go to with filled land, or are there any other problems with this suggestion?

  Thanks for the suggestion. I've reviewed the pile of earth and site in the light of what you said. The pile of earth is currently set back and heaped up from the proposed retaining wall line, and therefore higher than it will be eventually. I plan to move it down and graduating the land above the wall to a very very slight incline, and would make it about 1 m, not 1.3 to 1.5 as it initially appeared to be based on a purely visual assessment. If I fill the land below the wall very slightly, I could just get it to be a 900 mm wall, and that way, it would be below the threshold which Councils seemingly get uptight about getting structural sign-offs, etc.

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## Terrian

> Hi Terrian, 
> Concrete wall - i had the impression that is THE most expensive option of all.
> Structural engineer design, L footing hence need to excavate backwards into the higher area, rebars, formwork, and costly concrete. 
> (For me it's far inside the backyard so need concrete pump & hose run as well).

  ^^^ check the below thread  :Smilie:  http://www.renovateforum.com/showthread.php?t=72993   

> How much roughly did yours work out to all in, per m run and what height? 
> Ta,
> Ash

  rough cost was $600 for the 12m length, *BUT* I got all materials at very good prices !

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## Terrian

> Thanks for the suggestion. I've reviewed the pile of earth and site in the light of what you said. The pile of earth is currently set back and heaped up from the proposed retaining wall line, and therefore higher than it will be eventually. I plan to move it down and graduating the land above the wall to a very very slight incline, and would make it about 1 m, not 1.3 to 1.5 as it initially appeared to be based on a purely visual assessment. If I fill the land below the wall very slightly, I could just get it to be a 900 mm wall, and that way, it would be below the threshold which Councils seemingly get uptight about getting structural sign-offs, etc.

  could you build 2 walls, one above the other, the top wall set back by 500mm from the bottom wall ?

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## autogenous

_ I'm now rethinking re Autogenous' comment about lifespan - don't like the idea of redoing them later _ Moisture and Termites love wood sleepers. mmmmmmmmmm wood. 
Its a lot of work to redo. Have you looked at concrete panel/sleeper with H posts?

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## Ashwood

Terrian, thanks for the link.
Bloody solid looking wall you did, and for practically next to no cost, too!    

> could you build 2 walls, one above the other, the top wall set back by 500mm from the bottom wall ?

  Unfortunately, no, that wouldn't work for how i want to use the site. 
Cheers
Ash

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## Ashwood

> Its a lot of work to redo. Have you looked at concrete panel/sleeper with H posts?

  Hi Autogenous, 
Yes, that is what it is likely to be for me. Best compromise between ease of install, cost & aesthetics for my scenario. Any suggestions on product/supplier? 
Cheers
Ash

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## autogenous

> Any suggestions on product/supplier?

  Not in Melbourne.  
There is a big difference between the aesthetics of the product though.  
A good looking one should do the job.

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## Bleedin Thumb

> Moisture and Termites love wood sleepers. mmmmmmmmmm wood.

  
If you use CCA treated pine with a H4 treatment rating - they are guaranteed for 40 years - ( they are only guaranteed for this long as that is as long as they have been around, IE you probably will get longer as long as you treat any ends that you cut) 
Termites won't touch them and they are rated for inground use.  
My earlier comment about life span was related to a wall of over 1m where if it failed could cause property damage or worse. 
You have no worries with a small garden wall to 1metre.

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## Terrian

> Terrian, thanks for the link.
> Bloody solid looking wall you did, and for practically next to no cost, too!

  yeah, solid alright, when itcomes time to sell we want a developer to buy the place, and we want to see them get rid of the concrete around here (evil grin)   

> Unfortunately, no, that wouldn't work for how i want to use the site.

  pity, oh well, back to the drawing board  :Smilie:

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