Browse Forums Landscape & Garden Design Re: Rock walls - alternate for retaining? 3Mar 24, 2010 9:53 am Mrs Smith, That is a very good retaining solution. Most loose dirt will 'stand up' at around 33 degrees, steeper if it is compacted. This equates to roughly 1:1.5, or in other words 1.5 metres along for every 1 metre up. If you attempt to force material steeper than that it will exert a force on whatever structure you are using to retain it, hence the retaining structure needs to be 'engineered' for want of a better word to be able to cope with the forces. The steeper the retained face the more force is exerted. If you wanted to retain 1.2m high with a rock face, use 2m (horizontal) to do it and you should have no problems. You could easily make it steeper if you wanted to by burying half your bottom rocks, backfilling a bit and then burying your next rock behind it and so on to the top, that would be a strong structure as long as not too steep. The rock armouring on the slope is excellent erosion protection too (think the banks on either end of bridges - rock armoured to prevent water erosion in flooding). Establish vegetation on the slope for more soil satbilisation and you will have a very stable structure. Re: Rock walls - alternate for retaining? 4Mar 24, 2010 9:57 am Hi i have retaining rock walls kinda similar to the pics. They were there when i bought the property but i did re-construct parts of it. It is about 1 metre high and a bit higher in spots. The trick is to have a slope rather than a straight edge to the wall where you plonk the flatter rocks on the bottom and step up the slope. The soil then just slips between the rocks kinda binds it all together. I have clay soil, once it has all settled the drainage is excellent and the soil stops coming through the gaps. You can then plant in the gaps which also holds the soil back even more. I don't know about footings but if you place big rocks at the bottom (which looks natural anyway) then you don't have to really worry (thats what i did and copped a huge storm the other week no probs) . It all works fine and is perfectly stable once it binds the biggest problem you will have is with weeds in between the rocks which is a real pain. As long as you stack the rocks into the slope and not one on top of another it will be fine. It certainly isn't low maintenance but it does look natural and informal if thats what you are after. In one part I have a water feature running down the rocks into a pond and it looks great. Most of the rocks were already at the property but i did buy some for the local landscape supplier. I will post some pics when i get a chance. Re: Rock walls - alternate for retaining? 5Mar 24, 2010 10:03 am There's a rock retaining wall like you describe at the park just near us that looks fabulous ...I'll see if I can get a picture later. I have NO advice on the how-to though, sorry! Re: Rock walls - alternate for retaining? 6Mar 24, 2010 12:58 pm Thanks everyone! I really appreciate it! I'd love to see photos if you could please post them! It sounds lovely! Beatrix - did you build the water feature? It sounds absolutely lovely! Keen - thanks for the advice on making it steeper too! Are there any plants that are better than others? We have some limestone look-alike panel and post retaining, do you think it would look ok when it meets up with the rock wall? Re: Rock walls - alternate for retaining? 7Mar 24, 2010 1:06 pm Blog is now up - http://www.jbdave.blogspot.com/ Re: Rock walls - alternate for retaining? 8Mar 24, 2010 1:30 pm I think it will look fine. Post and panel is pretty formal looking, blend the boundary out with ground covers similar to those used on the rock wall cascading over the post and panel. Re: Rock walls - alternate for retaining? 9Mar 24, 2010 1:47 pm mrs_smith, Yeah i built the water feature its only a small cascade atm which will become a larger stream when i get the time. I forgot to mention it is actually quite hard and heavy work moving all the rocks while trying to place them to look natural. Its not a small job so to speak. Re: Rock walls - alternate for retaining? 10Mar 24, 2010 8:21 pm we had a big dry stone retaining wall at our previous house. No concrete. All the rocks were balanced and pressed back into the ground. Ours was not meant to have any plants in it but we found the grass ( cooch mostly) managed to work it's way into the gaps. But if you plant it heavily you might be fine. Re: Rock walls - alternate for retaining? 12Apr 01, 2010 10:49 pm I have done quite a few dray stone walls. I use limestone as it's cheap and easy to work with. Treat it as any wall and you will get good strength to it. You'll need a gympy hammer and a cold chisel and bolster for shaping the odd rock. Then there are those bloody cage things filled with rock. Someone will know what they are called They have some funny name. Re: Rock walls - alternate for retaining? 13Apr 02, 2010 7:27 am Re: Rock walls - alternate for retaining? 14Apr 02, 2010 11:37 am Those towers would be handy to string a line across and dry the socks and jocks on I always wondered with these, what stops the metal from rusting out and rocks falling. Have seen them used around bridges and on serious size walls. The rocks in them are often huge! Re: Rock walls - alternate for retaining? 15Apr 02, 2010 12:19 pm They get used a lot along freeways and major roads here, in median strip landscaping. One of my neighbours has put a few baby ones in his front yard, they're only about 400mm high. Looks like someone's trying to stop their rocks from escaping. I might try to sneak a photo later. It's mostly cacti and gravel with some yuccas; not to everyone's taste, but interesting. Re: Rock walls - alternate for retaining? 16Apr 02, 2010 12:33 pm You know what, that might be the very thing I don't like about them. For a landscape to be a successful one it must be at one with the natural environment. The use of natural materials. These essentially would not create a positive feel or energy for a garden design because they are holding the earth captive. It is being forced to be at one with the design, not appear as it would want to be there doing the job as with dry walls and brick walls. That's it! Now I have worked it out Thanks Kek. I look forward to seeing the earth contained in the cage breaking free Re: Rock walls - alternate for retaining? 18Apr 02, 2010 5:03 pm I quite like them in commercial landscapes - although the first time I saw them, I was all WTF?? Not so sure about domestic use - I guess it could be cheaper than engineering a fancy retaining wall though. Or possibly not. Re: Rock walls - alternate for retaining? 19Apr 09, 2010 5:57 pm I'm with you Fu, can't stand the look of them, they are butt ugly and to me scream out lazy, poor workmanship, passing trend. What happens when the steel rusts and the rocks do escape ?? Re: Rock walls - alternate for retaining? 20Apr 11, 2010 7:08 pm Then nature sets them free making the landscape finally something to be admired Like having a canary in a tiny cage You would never see stone work or rocks treated like that in a Japanese or Chinese landscape (these are the pinnacle of landscape design and understanding in the concepts). The rock or stone is something treated with the utmost respect and care. It is an art form to place and use them correctly and the skills are well sought after. I could never imagine them wanting to cage such an important element of a landscape After all a stone has seen so much more than you or I and has seen the evolution of the landscape it has been in for it's entire time all the while changing slightly to adapt. That is a bit Zen isn't it Hi all, I have been looking at land in South Australia, that is on a slope however most of the core excavation is complete, with a flat area to place a house. The agent… 0 1753 Nope, only on the inside, I've literally has my ears to the brick outside and can't hear anything. I can sort of 'reset' the noise by pressing firmly on the studs. This… 10 14143 Oh no! I would use a can of expandable foam ( there are some that will take render) then cut it back and render over the top 1 5303 |