Hi, our land has several elevation levels. The lowest area is unfortunately very difficult to access with machinery, so everything needs to be transported and installed manually. There is an existing slope about 120cm (47 inches) high made of stable (so it doesn’t slide on its own) but muddy stone/muschelkalk/mud/clay that needs to be retained. Only foot traffic will occur on the plateau, so there will be no additional load from vehicles or similar.
I have ordered steel H-beams, which I will set in concrete. In the recesses of the beams, I plan to insert 10cm x 10cm (4 inches x 4 inches) squared timbers (I have plenty leftover from construction) from above. Against the slope, I will install a dimpled membrane and drainage gravel, and possibly a drainage pipe. I think this will hold.
What I’m unsure about is whether I can stack the untreated timbers directly on top of each other (they can’t be treated now because of the current weather) or if I should use spacers (for example, nuts) to allow some ventilation. Of course, the dimpled membrane must never be damaged, otherwise all the muddy water will flow through. I’m concerned that stacking the timbers directly without ventilation might cause the entire wall to rot.
Best regards
I have ordered steel H-beams, which I will set in concrete. In the recesses of the beams, I plan to insert 10cm x 10cm (4 inches x 4 inches) squared timbers (I have plenty leftover from construction) from above. Against the slope, I will install a dimpled membrane and drainage gravel, and possibly a drainage pipe. I think this will hold.
What I’m unsure about is whether I can stack the untreated timbers directly on top of each other (they can’t be treated now because of the current weather) or if I should use spacers (for example, nuts) to allow some ventilation. Of course, the dimpled membrane must never be damaged, otherwise all the muddy water will flow through. I’m concerned that stacking the timbers directly without ventilation might cause the entire wall to rot.
Best regards
K
knalltüte2 Jan 2021 18:10That will happen anyway if the wood is regular spruce or fir, whether you use a dimpled membrane or not. Only the timing will change.
I generally think it’s a good idea to upcycle “waste wood,” but in this case, in my opinion, it won’t be sufficient.
You would have to use the rough, oil-soaked old railway sleepers that were often used outdoors decades ago. They last longer, but not forever either. Alternatively, expensive tropical hardwood (or is there any local wood suitable for this?) that is appropriate for such uses.
Planting the slope so that it becomes well-rooted is always a good option, but it probably won’t be enough and will take too long here.
As you can see, your solution works but isn’t permanent. I’m also not a fan of L-shaped retaining walls, but I think they would be appropriate here. Especially to better withstand earth pressure compared to T-beams embedded in concrete (how deep?).
I generally think it’s a good idea to upcycle “waste wood,” but in this case, in my opinion, it won’t be sufficient.
You would have to use the rough, oil-soaked old railway sleepers that were often used outdoors decades ago. They last longer, but not forever either. Alternatively, expensive tropical hardwood (or is there any local wood suitable for this?) that is appropriate for such uses.
Planting the slope so that it becomes well-rooted is always a good option, but it probably won’t be enough and will take too long here.
As you can see, your solution works but isn’t permanent. I’m also not a fan of L-shaped retaining walls, but I think they would be appropriate here. Especially to better withstand earth pressure compared to T-beams embedded in concrete (how deep?).
P
pagoni20202 Jan 2021 18:16I once built something similar, using so-called planting stones to construct "towers" about 1 meter high (3 feet), which I then filled with concrete. Behind that, I placed three wooden boards stacked on top of each other, just like you seem to want to stack your wooden beams now.
To prevent the soil from coming into direct contact with the wood, I put a kind of roofing felt between the soil and the wood, and it has held up well for almost 20 years. Although I used pressure-treated boards, to be honest, that probably didn’t matter much.
If I were you, I would do it this way. If any part ever starts to rot, you can always repair it then or eventually replace it with another material as a protective wall. Until then, you have several years before that happens.
The wood outdoors is exposed to the elements from all sides anyway. I would skip painting it — it might only last a few months longer with paint anyway.
Keep it as simple as possible... I like it!
To prevent the soil from coming into direct contact with the wood, I put a kind of roofing felt between the soil and the wood, and it has held up well for almost 20 years. Although I used pressure-treated boards, to be honest, that probably didn’t matter much.
If I were you, I would do it this way. If any part ever starts to rot, you can always repair it then or eventually replace it with another material as a protective wall. Until then, you have several years before that happens.
The wood outdoors is exposed to the elements from all sides anyway. I would skip painting it — it might only last a few months longer with paint anyway.
Keep it as simple as possible... I like it!
So, there is basically no alternative to my plan... the question was only whether to include a ventilation gap or not. But you are probably right: it doesn’t make much or any difference. I have large amounts of construction timber, formwork panels, etc. left over that must be used; the last wood container cost 500 € and was just a drop in the ocean... therefore the rule is: use it (treehouse, fence, garden bed edging already done), burn it, give it away... I cannot use L-blocks there, nor bricks, hollow blocks, or the huge amounts of concrete needed for foundations... everything has to be carried there and underneath: that’s not feasible (at least not without several “helpers” carrying it for days).
The steel beams (70-80 cm (28-31 inches) deep, deeper is not an option because of the soil) will outlast me and could potentially be fitted with new timber beams later on. I hope/think the wood will last at least 10-15 years?! The slope behind will gradually compact over time and probably won’t shift noticeably if the timber beams are replaced.
The steel beams (70-80 cm (28-31 inches) deep, deeper is not an option because of the soil) will outlast me and could potentially be fitted with new timber beams later on. I hope/think the wood will last at least 10-15 years?! The slope behind will gradually compact over time and probably won’t shift noticeably if the timber beams are replaced.
P
pagoni20202 Jan 2021 19:53I completely agree.
What could be better than being able to use your existing materials? That’s great.
If you have too much, you can always lay it double. In a few years, if something rots, the slope will be stable anyway (as with me).
The steel beams are good, too; it’s not like it’s in the living room. I always prefer that kind of solution over all the expensive DIY store system kits.
What could be better than being able to use your existing materials? That’s great.
If you have too much, you can always lay it double. In a few years, if something rots, the slope will be stable anyway (as with me).
The steel beams are good, too; it’s not like it’s in the living room. I always prefer that kind of solution over all the expensive DIY store system kits.
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