Building oak sleeper retaining wall - is this a correct way?

[GloriousEuropa]

That's something I'd be wondering too. I'd be thinking of maybe a return at both ends or anchoring into the ground, and maybe stepping the higher ones further back...

It's not something I have much experience in, my first thought would be will it be strong enough to hold back the weight of the soil (and rain water!), especially as it's bordering a public road.

Sorry that picture is so inaccurate and the soil lawn level way too high. I've drawn a far more accurate one now (still still terrible at drawing)

I've now added a concrete footing with the bottom oak sleeper with a stainless steel coach bolt in it (rebar corrodes against soil I believe)

Hi

the first thing to check is how high is this wall. You have drawn 5 sleepers so is it 50cm? How long is it also?

I am not a structural engineer but the first thing to be aware of is that you should seek advice from one if the wall is over 1m. I would want to be quite confident over the strength of the wall because if it collapses on to the public highway you will be liable!

The other thing that may come into it is how long the wall is. Obviously the idea of the gravel is to aid drainage to avoid water pressure and freeze thaw action pushing it over. Make sure the gravel is angular not rounded. You could also have weep holes or a french drain at the bottom to ensure water escapes.

In terms of tying it together, you could use rebar through the sleepers to pin them. Another thing you could to add strength is to put geogrid down.

I suppose to keep the timbers from rotting you could add sone kind of membrane behind them or paint with some waterproofer much as you would with a block wall.

Sorry, the wall should only need to come slightly above the front lawn, which is 35cm high. So the sleeper protruding 38cm? I've drawn an image above to show the front of the lawn next to the public road, but this is how it is all supposed to look to scale. The guy doing the drive is supposed to be figuring this all out himself, but we're about to drop him as soon as I post this as he's just not communicating. He tasked us with getting the sleepers, which we did, but now he hasn't asked how we'd want them, what the options are, etc.

This is the general plan of what we're having with a resin drive. Ignore how many sleepers there are. It's just a texture not individual sleepers. But they'll only be three high above public road level, so 4 total at a maximum.

My SIL inherited a sleeper retaining wall in his garden approx 4 feet high. I dont know how it had been up but he had to replace it after about 7 years as it was disintegrating.

Not sure I would risk next to a public road.

Oh dear. Was it softwood? Ours is Latvian oak. And this is why I want all the correct things in place to make it last. Ours is not 4 feet high though. Literally half of that.

 

[daviesm1976]

Really i think a wall just over a foot high wouldnt be under a significant load and obviously even if it toppled there is a low risk of injury.

Id still have some gravel behind and pin each sleeper to the one below with stainless steel threaded rods /fixings/ brackets or similar. Maube you could leave a weep vent in places by leaving small gaps between the ends but i would just crack on

 

[GloriousEuropa]

Really i think a wall just over a foot high wouldnt be under a significant load and obviously even if it toppled there is a low risk of injury.

Id still have some gravel behind and pin each sleeper to the one below with stainless steel threaded rods /fixings/ brackets or similar. Maube you could leave a weep vent in places by leaving small gaps between the ends but i would just crack on

Thank you sir. I might bloody have to at this rate, because as I said the guy doing the driveway just isn't advising on any of this or coming around. But I would seriously have a go myself but I'm unsure where the utility lines are, don't know how to use a cat and genny, etc.

 

[daviesm1976]

You can register with a website for free and providers will send rough maps of where services are. They are called something search before you dig. I found where my electric internet etc were routed before i did some landscaping of the front garden but could only guess where the gas is from manholes in the pavement street etc.

Obviously not safe to fully rely on it as they may not be buried to the correct depth or take a direct route etc.

 

[GloriousEuropa]

You can register with a website for free and providers will send rough maps of where services are. They are called something search before you dig. I found where my electric internet etc were routed before i did some landscaping of the front garden but could only guess where the gas is from manholes in the pavement street etc.

Obviously not safe to fully rely on it as they may not be buried to the correct depth or take a direct route etc.

Thanks. I think I applied to one last September - https://www.linesearchbeforeudig.co.uk/

Both the electrics and water companies are still on "await response".

 

[scbk]

Thanks. I think I applied to one last September - https://www.linesearchbeforeudig.co.uk/

Both the electrics and water companies are still on "await response".

Round here you can just phone up the power company (hydro board/sse) and they can send plans over, and send a man out with a CAT scanner within a day or two.
Not much you can do with the water other than diving rods, the plans usually aren't right, and the pipes will be plastic.

 

[scbk]

The other thing that may come into it is how long the wall is. Obviously the idea of the gravel is to aid drainage to avoid water pressure and freeze thaw action pushing it over. Make sure the gravel is angular not rounded. You could also have weep holes or a french drain at the bottom to ensure water escapes.

Why do you say angular? IMO round gravel lets more pass water through (more air gaps)

 

[daviesm1976]

I think the idea is that it is easier to compact and less likely to shift around so settlement is less likely. Most videos ive seen suggest 20mm or so size.

I suppose it is similar to permeable bedding layers; you dont use pea gravel as it has no strength.

 

[Halitosis]

I've seen sleeper wall designs where holes are drilled vertically down through all sleepers into which steel rods are placed and filled with cement thereby holding the whole wall together (edit - found and added the link below). The bottom sleepers need to be well anchored. Drainage could be resolved with weep holes every couple of feet at ground level (ensure they're at least an inch so they don't easily get blocked).Pavingexpert.com has some great advice specific to sleeper retaining walls https://www.pavingexpert.com/featur08
The gravel and (presumably porous) membrane in your first picture is a good idea - especially if your soil doesn't drain too well.
Alternatively I used modular walling - super easy like lego to build once the first course is laid and level, with no mortar and so it allows water to drain through

 

[GloriousEuropa]

I've seen sleeper wall designs where holes are drilled vertically down through all sleepers into which steel rods are placed and filled with cement thereby holding the whole wall together (edit - found and added the link below). The bottom sleepers need to be well anchored. Drainage could be resolved with weep holes every couple of feet at ground level (ensure they're at least an inch so they don't easily get blocked).Pavingexpert.com has some great advice specific to sleeper retaining walls https://www.pavingexpert.com/featur08
The gravel and (presumably porous) membrane in your first picture is a good idea - especially if your soil doesn't drain too well.
Alternatively I used modular walling - super easy like lego to build once the first course is laid and level, with no mortar and so it allows water to drain through

Thanks for the link mate. I'll give it a thorough examination now.

Does your modular walling bricks have no mortar holding them together?

 

[Halitosis]

No - literally just sit the blocks on top of each-other and they have a lip that hooks over the back of the block below that provides the strength. Mine is made by Tobermore but a few manufacturers do equivalents. Probably a bit more pricey than sleepers mind