Browse Forums Landscape & Garden Design 1 Oct 13, 2012 6:08 pm I saw somewhere recently that ppl use stormwater pipes for drainage instead of perforated ag pipes. They cut in some slots half way through with angle grinder and voila - much easier to create the required angle etc. So, what are people's thoughts, experiences etc. and are there any other types of drainage pipes than these two? My signature is distracting people from my wise posts ... Re: Types of site drainage pipes ?!?!?! 2Oct 13, 2012 7:50 pm Yep there are drainage pipes as you described that can be bought. The advantage they have is if they get blocked by roots or soil etc they can be cleaned out with a "worm" that the plumbers use to clear drains. The black coiled slotted pipes don't clean out well due to the ridges. But really the coil is for subsurface draining (turf/retaining walls) and the cut slot pipe is more for "french" drains. Re: Types of site drainage pipes ?!?!?! 3Oct 14, 2012 11:48 am Thanks, BK So why not use the sw pipes with slots behind the walls etc. as well? It seems to me that they are much better than the coil pipes ... My signature is distracting people from my wise posts ... Re: Types of site drainage pipes ?!?!?! 4Oct 14, 2012 12:19 pm The slotted pipes are good for behind walls and their smooth bore means the water runs away quickly. The fact that they are hard walled straight pipes means they are harder to lay correctly than the coil pipes. Because of this they are usually only sold by plumbers merchants rather than DIY stores. The Harder You Try - the Luckier You Get ! Web site http://www.anewhouse.com.au Informative, Amusing, and Opinionated Blog - Over 600 posts on all aspects of building a new house. Re: Types of site drainage pipes ?!?!?! 5Oct 14, 2012 7:20 pm bashworth The fact that they are hard walled straight pipes means they are harder to lay correctly than the coil pipes. Because of this they are usually only sold by plumbers merchants rather than DIY stores. Or are there some other special pipes that we cannot ever see anywhere in shops? My signature is distracting people from my wise posts ... Re: Types of site drainage pipes ?!?!?! 6Oct 14, 2012 7:45 pm With straight pipe you need to be able to either dig a trench with an even fall to properly support the pipe (or be very careful with the pipe surround) You also need to wor.k with a limited range of bends The Harder You Try - the Luckier You Get ! Web site http://www.anewhouse.com.au Informative, Amusing, and Opinionated Blog - Over 600 posts on all aspects of building a new house. Re: Types of site drainage pipes ?!?!?! 7Oct 15, 2012 5:07 am Most gardening supply places will now have 90mm slotted storm water pipe in 6M lengths and bends.(ring around), so it's not hard to buy but keep in mind 6M long. So you will need a roof rack or get them delivered or you can buy them in Bunnings 3M long. Also Bunnings has a good stock of bends, joiners and anything else you need. Yes they are little harder to lay than flexible coil and a little more skill is required but a much better job and it's easier to have inspection openings (for cleaning) by putting in "T" joiners, and easier to clean as BK said. Foremost Building Expert in Australia,assisting with building problems/disputes, building stage inspections,pre-contract review advice for peace of mind 200 blogs http://www.buildingexpert.net.au/blog Re: Types of site drainage pipes ?!?!?! 8Oct 15, 2012 7:42 am Aaaaa ... I see, thanks. So, would it be ok to lay it in a bed of 10mm blue metal? taking care that I don't leave large gaps underneath the pipe here and there ... Also, just crossed my mind ... if Bgs don't have the slotted pvc pipe, they could probably get it for me as a special order ... I would need just over 3m length ... But also, would I need a 100mm pipe or 90?? And BTW, the design of the coil / ag pipe is beyond my comprehension. I just cannot see for the life of me how something like that can be useful to transport water and not let any through. It's mind blowing Or maybe it's designed to actually kepp letting water through and to transport only a tiny portion away ... ?! Actually, how can it transport anything at all! with all those holes at the bottom! I'm stuck in this My signature is distracting people from my wise posts ... Re: Types of site drainage pipes ?!?!?! 9Oct 15, 2012 10:46 am Lex And BTW, the design of the coil / ag pipe is beyond my comprehension. I just cannot see for the life of me how something like that can be useful to transport water and not let any through. It's mind blowing Or maybe it's designed to actually kepp letting water through and to transport only a tiny portion away ... ?! Actually, how can it transport anything at all! with all those holes at the bottom! I'm stuck in this You are not just transporting water with slotted pipe, You are draining a waterlogged soil. The soil will be wet below the pipe but the water will drain out to the level of the bottom of the pipe. If you didn't have slots on the bottom the water would only drain out to the level of the lowest slot! The Harder You Try - the Luckier You Get ! Web site http://www.anewhouse.com.au Informative, Amusing, and Opinionated Blog - Over 600 posts on all aspects of building a new house. Re: Types of site drainage pipes ?!?!?! 10Oct 15, 2012 12:11 pm Still dont get it. Here comes my argument (from my limited understanding of the design principles behind the ag pipe). The slots at the bottom cannot possibly move the water anywhere, they cant even keep it in the pipe - because the slots are at the bottom and water just gets out via the slots. On the other hand, if I put slots into pvs pipe half way thru, water will get into the pipe easily and not spill out of it unless water level in the pipe is higher than the slots can reach (which is half way). So confusing My signature is distracting people from my wise posts ... Re: Types of site drainage pipes ?!?!?! 11Oct 15, 2012 3:17 pm Water on the outside of the pipe. Above the level of the bottom of the pipe will always drain into the pipe because the water will always run down. Water cannot drain out of the slots at the bottom because the soil/gravel below the pipe is water logged as it has nowhere to go. See the diagrams at this link http://www.anewhouse.com.au/?p=3902 The Harder You Try - the Luckier You Get ! Web site http://www.anewhouse.com.au Informative, Amusing, and Opinionated Blog - Over 600 posts on all aspects of building a new house. Re: Types of site drainage pipes ?!?!?! 12Oct 15, 2012 5:20 pm bashworth Water cannot drain out of the slots at the bottom because the soil/gravel below the pipe is water logged as it has nowhere to go. Anyway, was going to eventually do some testing of the ag pipe to see what is does and what it doesn't do ... I guess this ^ bit cannot be tested then ... or my "lab" will have to be redesigned My signature is distracting people from my wise posts ... Re: Types of site drainage pipes ?!?!?! 13Oct 15, 2012 5:27 pm Hi Lex The important point here is that the trench bottom in which pipe is laid is also excavated with a grade towards storm water pit. That will allow water below the pipe to drain also(slowly). Otherwise you will have underground water reservoir that cannot drain. You will not need 100mm diameter pipe and yes you can make your own slots in the pipe with a grinder if required. Foremost Building Expert in Australia,assisting with building problems/disputes, building stage inspections,pre-contract review advice for peace of mind 200 blogs http://www.buildingexpert.net.au/blog Re: Types of site drainage pipes ?!?!?! 14Oct 15, 2012 6:16 pm building-expert Hi Lex You will not need 100mm diameter pipe and yes you can make your own slots in the pipe with a grinder if required. As a drainage engineer I would not recommend cutting the slots yourself. Get it wrong and the pipe can collapse rendering it useless. The Harder You Try - the Luckier You Get ! Web site http://www.anewhouse.com.au Informative, Amusing, and Opinionated Blog - Over 600 posts on all aspects of building a new house. Re: Types of site drainage pipes ?!?!?! 15Oct 16, 2012 11:53 am OK, so what is the name (I mean name like ag pipe, not the brand name) of that ready made pipe with slots and where can I order it from?? I've never seen them anywhere, even on the internet. My signature is distracting people from my wise posts ... Re: Types of site drainage pipes ?!?!?! 16Oct 16, 2012 3:53 pm Hi Lex It's 90mm slotted storm water drain (Vinidex) available from garden supplies, Bunnings or plumbing supplies like Reece, or irrigation supplies. Very common, no big deal. Foremost Building Expert in Australia,assisting with building problems/disputes, building stage inspections,pre-contract review advice for peace of mind 200 blogs http://www.buildingexpert.net.au/blog Re: Types of site drainage pipes ?!?!?! 17Oct 16, 2012 4:00 pm The full description is "Slotted rigid pipe uPVC to AS 2439.1" Plumbers merchants are the most likely source. The Harder You Try - the Luckier You Get ! Web site http://www.anewhouse.com.au Informative, Amusing, and Opinionated Blog - Over 600 posts on all aspects of building a new house. Re: Types of site drainage pipes ?!?!?! 18Oct 17, 2012 6:02 am i actually went and priced this flexible slotted ag pipe at bunnings yesterday for our retaining (as well as the RELN storm drain system for the front of the walls) the 65mm diameter pipe at 20m long was $37, the 100mm at 20 meters long was $63 and the 100m x 10 meters long was $31 is this slotted flexible pipe the best for drainage behind retaining? how much of a slope do i need over 25 meters to ensure adequate water removal from behind the wall? im hearing geotextile fabric is the way to go down the back of the wall and then wrapping it under the pipe, but im worried about water coming out the slots on the bottom of the pipe and getting in/sitting under the bottom row of sleepers. really dont want to stuff this up as its essential to have good water drainage behind timber walls Re: Types of site drainage pipes ?!?!?! 19Oct 17, 2012 7:49 am The drainage behind retaining wall has the main purpose of preventing build up of hydrostatic pressure in the soil and the flexible pipe is fine for that. If you surround it with 3/4 crushed rock aggregate or scoria and use geotec fabric you will be fine. Small amount of water below the pipe won't matter. Foremost Building Expert in Australia,assisting with building problems/disputes, building stage inspections,pre-contract review advice for peace of mind 200 blogs http://www.buildingexpert.net.au/blog Re: Types of site drainage pipes ?!?!?! 20Oct 18, 2012 9:40 pm Not sure if I mentioned that this is not a retaining wall application. We probably need it along one part of the house slab ... I'm still inclined to think the solid pipe with manual slots (or ready made) is better than ag pipe. We do have some low retaining walls and I noticed that the soil is badly waterlogged to the point that it stinks badly and is overly wet We're talking about new walls, not some old thing that needs to be renovated. And yes, it's the ag pipe On the other hand, we did have record falls too My signature is distracting people from my wise posts ... 4 5117 As most others have posted above the install isn't compliant. The pipe is meant to be covered in loose soil or sand, the pipe has holes in it that leaks out a termicide… 10 5728 Building Standards; Getting It Right! Thank you for the generous offer. I need to get the plumber out to give me an explanation. As mentioned I haven't seen any rain water discharge from pipes 1& 3. It… 7 10819 |