Browse Forums Landscape & Garden Design 1 Oct 14, 2010 7:11 am Hi I got a retaining wall done by a professional and there are few issues: (a) He has not installed black plastic (or similar material) between timber retaining wall and soil. When asked, said timber which has used is treated pine and it does not make much different. Is this true? (b) He has cut Galvanized posts on top to get the retaining wall leveled. After a week, I noticed corrosion has occurred. What should I do now? (c) Most of timber sleepers he has used is not level on surface, bend etc. This makes entire wall bend and not leveled. Is he allowed to use this kind of timber? Thanks, Re: Retaining Walls 3Oct 14, 2010 1:36 pm let me answer a few qs. Firstly, you do not need black plastic sheeting behind the timber. Most ppl install it as it is suppose to make the timber last longer from rotting etc, however with propper drainage, this will cause no threat. Secondly, Treated pine sleepers are prone to massive amounts of warping or bending when they get wet and dry out. This is the reason i HATE "H" channels for retaining walls as oppose to the old style of bolting them into a sleeper. The old style means they dont warp, or they dont warp much. H channels leave a nasty gap and i have seen dozens of warped retaining walls. The H channels are alot easier and quicker for tradies, hence why they do them like that. As for the rust...well he shouldn't have cut them. That is just plain stupid. He should have run stringlines to get the H channels level. most of the time the H channel is lower than the final sleeper so the sleeper sits higher than it. They would have been damn hard to cut, that steel is very very solid and very very heavy......Did you need a permit to get your wall done? as for "is he allowed to use this timber". The answer is yes. Re: Retaining Walls 4Oct 14, 2010 8:41 pm Hi Thanks for your above comments, really appreciate it. (a) Could you explain more what do you mean by "proper drainage" and how to do it properly? (b) What should I do to the areas which corrosion has occurred? Should I ask that guy to replace them? (c) One retaining wall is 1.2m high and the other is 1m high. That guy said no need to get a permit. (d) He has charged money for galvanized posts: 1.2m below and above ground - 1st retaining wall and 1m below and above ground - 2nd retaining wall. But he has used 50-60cm below ground. This means 1.2m above ground and 60cm below ground and 1m above ground and 50cm below ground posts. Do you think this wall hold soil? Thank you. Re: Retaining Walls 5Oct 14, 2010 10:54 pm I hate to say it, but the guy that built ur wall is a moron. Firstly u didn't tell me which area u live in so I can't advice on local law however in my area and most of Vic, anything 1m in height or over, or any height less than 1 meter from. Boundry requires a permit. Secondly, the engineering spec requires that however high a wall is, the footings must be the same or more in the ground with an approximate 5 percent lean backwards, to compensate for movement. Thirdly, proper drainage requires that ag pipe be laid on a bed of scorrier rock or some sort of rock, and backfilled with the same rock. The water must drain away to either a pit or somewhere on ur land that can handle the water run off. The galvanized posts should not have been cut but u can fix this by grinding off the rust and painting some rust guard on them, it's in the paint section at bunnings. Wether it will hold or not I cannot tell u, but please don't tell me that he used quick set concrete for the posts..... Also, don't be worried, I don't want u to die from stress. These engineering specs are always over engineered for worst case scenario. Call ur local council find out what requirements are for a permit and then go from there. Can u also post pics, it's hard to tell without seeing it. Re: Retaining Walls 8Oct 15, 2010 9:21 am Wow! I'm in berwick too! Our council is quite strict on retaining walls as berwicks land is very hilly and heavy clay. Which estate r u in ? No I'm not in this trade but I did build a 30 meter retaininng wall 1 meter high so I've got quite a bit of experience on this matter hehe Re: Retaining Walls 9Oct 15, 2010 10:57 am Hi oohsam, oohsam Secondly, the engineering spec requires that however high a wall is, the footings must be the same or more in the ground with an approximate 5 percent lean backwards, to compensate for movement. So, are you saying that for a wall that is 700mm above ground, there should be at least 700mm of "wall" (ie. some sort of footing) under ground? Does "compacted" rock in this case count as footing, or should there be a concrete footing? And are you talking about block style of walls, like Tasman blocks, or does it not matter what material is used? oohsam Thirdly, proper drainage requires that ag pipe be laid on a bed of scorrier rock or some sort of rock, and backfilled with the same rock. The water must drain away to either a pit or somewhere on ur land that can handle the water run off. For sites sloping down away from the walls, are pits really required? How do we figure if we really need a pit or not? Is that based on the amount of soft surfaces / soil which is contained by the wall, or do even hard concreted surfaces count?? oohsam The galvanized posts should not have been cut but u can fix this by grinding off the rust and painting some rust guard on them, it's in the paint section at bunnings. Where does this galv post go?? I never saw posts in retaining walls My signature is distracting people from my wise posts ... Re: Retaining Walls 10Oct 15, 2010 11:23 am Hey Lex. Well, we're talking about treated pine timber retaining walls, so the (length in/length up rule) does not apply to block/brick walls. Put simply, if its a sleeper wall, the POST, ie, H beam or sleeper, must be the same length in the ground than the walls height. So for a 700mm sleeper wall, you would need 700mm of post in the ground, 700mm of post out of the ground.... Pits are not always required. I was stating that when using AG pipe behind the wall, you cannot just let the water run off into the street or onto your neighbours property unless your land can handle water run off. (there will always be a pit or drainage point somehwere on your land as builders are required to provide drainage from your storm water etc.) The galvanised post is called a H beam. here is a picture of it Re: Retaining Walls 11Oct 15, 2010 11:27 am Oh one more thing, when considering building a retaining wall, you must Always consider drainage, no matter the material used. that being, brick, masonry block, or those slot together systems. Water is the biggest cuase of wall collapses as it adds an obscene amount of force behind the wall. AG is the most commonly used method. Here is a pic of what im talkin bout. Re: Retaining Walls 12Oct 15, 2010 3:30 pm Pine !! Anyways ... I'm having a bit of trouble getting various landscapers (including concretors!) to tackle the drainage issue. I somehow thought that they would know these things and that I wouldn't need to ask and if I did, that they would already have a solution in mind ... but they seem to scratch their heads at first. Not very encouraging !! Trouble is, we have a sloping backyard and there is no stormwater whatsoever on our site, except for water tank overflow at the front which is piped into street gutter - whihc is uphill from the backyard!! I even started a thread on our site drainage ... not sure if you could comment on our situation oohsam ? .... http://forum.homeone.com.au/viewtopic.php?f=19&t=39591 ... so not sure how much water there would be collected behind that wall (the pic is not quite accurate as there would be a small garden bed between the retaining wall and the slab, around 70cm wide or so). My signature is distracting people from my wise posts ... Re: Retaining Walls 13Oct 15, 2010 8:14 pm Hi oohsam I am in Berwick Chase. Both of Retaining walls in my place are not straight. The guy who completed the walls would be here to get them straight. I will ask him to install a proper drainage system as mentioned by you. Also, I will ask him to fix the galvanized post which got corrosion. Once he finished, I would like to get someone to check these walls. Do you know someone who does this kind of work? I am having problems uploading photos. Have you got an email address? Thanks Re: Retaining Walls 14Oct 15, 2010 8:37 pm http://img820.imageshack.us/i/11316470.jpg/ http://img709.imageshack.us/i/79803505.jpg/ http://img163.imageshack.us/i/50278033.jpg/ http://img508.imageshack.us/i/12407669.jpg/ http://img230.imageshack.us/i/59616696.jpg/ http://img821.imageshack.us/i/86019349.jpg/ http://img508.imageshack.us/i/24198963.jpg/ http://img408.imageshack.us/i/67544390.jpg/ -- Have attached some photos -- http://img709.imageshack.us/i/81983780.jpg/ Re: Retaining Walls 15Oct 15, 2010 9:12 pm Im no expert but I've done a retaining wall using universal column section (H Beam) and sleepers and I'm currently doing 45m of retaining walls using the wooden post system. I totally agree with what oohsam is saying. I personally think that the galv steel post option is great for boundary walls which you can't see such as when you are on the high side and can't actually see the exposed wall as it is easy and strong and also lasts. However for walls which you can see they are pretty ugly for the reason oohsam mentioned - the sleepers will warp alot. The pictures you have posted are pretty much indicative of what the H beam system looks like once the sleepers have warped. Its hard to see from the photos if the posts are all lined up as they should be but otherwise it all looks pretty standard - those sleepers are your typical H4 ironwood variety that is commonly used. It's a pitty that this has been used for retaining walls that are in a sense a feature of your property as they will allways be seen (unless you can grow plans in front of them). I definetly would have used the wooden posts as they keep the sleepers straighter and they look much more natural so that the imperfections of the sleeprs actually add to the look. Steel posts look like someone put mag wheels on a horse cart - it just looks wrong. The scoria gravel you posted a picture of is also the usual material used for the drainage system. If the sleepers are only 500mm in the ground however that is pretty *** poor. Re: Retaining Walls 16Oct 15, 2010 9:21 pm Hi Lex, I'm in Sydney if you want me to have a look Where you are coming from is where you are going to... Re: Retaining Walls 17Oct 15, 2010 10:00 pm Hey onc, thank you for your offer! I think you just want to meet me ... and maybe give me an obscene quote that I cannot not refuse We have two more quotees tomorrow (so far). Both sound like "serious" concretors and they deal with slabs as well as driveways. We'll see what comes out of that! Our site is more complicated since it's a total makeover and they apparently have to do the soft stuff in the backyard first (total turf replacement), some retaining walls at the back and only then do the concreting, then finish off front soft stuff/turf. And the soft landscaping guys have to communicate with the concreting guys Oh, and my favourite - the drainage !! My signature is distracting people from my wise posts ... Re: Retaining Walls 18Oct 15, 2010 10:17 pm Well the offer is there I'm only here til Tuesday... it is amazing what another pair of eyes and somewhat of a brain can do. Where you are coming from is where you are going to... Re: Retaining Walls 19Oct 16, 2010 2:10 am NCQG - The markings of the sleepers you have taken are not a big deal. Keep in mind, this is timber, and trees do not grow on a canvas and thus, are not identically perfect! In fact I think it adds character. The white stuff, and marks, are all from the flat pack, and the knots are just normal, so I wouldn't be getting upset at that. Ideally it would have been good to see more pictures of the actual wall instead of defected individual sleepers. I cant see any form of drainage behind those sleepers and am trying to work out why you needed a retaining wall int he first place. Its not retaining or holding anything up....if its to retain that dirt u have there...well you could have had the wall much further back. Anyway, too little to late now to be making those adjustments.... The reason the guy told you that 500mm into the ground is fine is simply because your wall has no force on it. Its a freestanding wall. There is nothing that it is actually retaining.... So unless there are more angles that I cannot see, there seems to be nothing really wrong with the wall. The sleepers will warp in there, as there is a gap, that's just something that is going to happen. Oh and as for drainage. I don't see a point in putting drainage. as no water will collect up...as, there is nothing that the wall is retaining for water to get trapped! Re: Retaining Walls 20Oct 16, 2010 7:18 am NcgQ http://img820.imageshack.us/i/11316470.jpg/ http://img709.imageshack.us/i/79803505.jpg/ http://img163.imageshack.us/i/50278033.jpg/ http://img508.imageshack.us/i/12407669.jpg/ http://img230.imageshack.us/i/59616696.jpg/ http://img821.imageshack.us/i/86019349.jpg/ http://img508.imageshack.us/i/24198963.jpg/ http://img408.imageshack.us/i/67544390.jpg/ -- Have attached some photos -- http://img709.imageshack.us/i/81983780.jpg/ I did consider fixing your pics so they would show in the thread but they come up quite large unless you select the thumbnail option and copy the code for forum. In which case they are a bit small as you can see by the example below. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Render your bathroom walls, two opinions versus the one, makes you wonder. 3 6062 The spacing of the studs looks pretty large especially for a load bearing wall. 3 11116 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 11764 |