Browse Forums Building Standards; Getting It Right! 1 Jun 18, 2016 2:11 am Hi all, We're currently building and I've got an issue where stormwater pipes have the incorrect gradient. Despite having sufficient fall to an underground main outlet pit, it looks like the pipes have been laid so water backs up. I'm told by the SS that this is not an issue as pipes hold water and they don't leak. It's not according to the drainage plan design in that its not flowing the correct way. Has anyone else had this issue and how has the builder responded? I'll be raising it with my independent inspector but keen on hearing anyone elses views. Thanks in advance. Re: Gradient of underground stormwater pipes 2Jun 18, 2016 8:39 am Correctly laid stormwater pipes have a constant gradient, and should be dry if there is no flow. The only exception would be if you are in an area where soakpits are used when it may take some time for the pipes to drain after very heavy rain. 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: Gradient of underground stormwater pipes 3Jun 18, 2016 8:48 am Thank you Bashworth. There are no soakpits that are used. I am very confident that the pipes have been laid incorrectly. We're near the final inspection and I don't want this to hold up handover but ill guess that the builder will fight it as it wont be cheap to repair (dig up and re-lay main runs i assume). Keen to hear if ppl often find this as an issue and whats done to rectify. The plumbing commission are pretty clear the gradient should be correct in their audit checklist: http://www.vba.vic.gov.au/__data/assets ... mwater.pdf FYI - I purchased your inspection kit and will be using it - thanks. I'm in Melbourne as well Re: Gradient of underground stormwater pipes 4Jun 18, 2016 10:58 am They are supposed to be at 1:100 minimum unless that gradient is unachievable due to site constraints. If that is the case then inspection openings at major junctions and at regular intervals must be installed. http://www.vba.vic.gov.au/__data/assets ... -Grade.pdf Personally, I'd never get our plumbers to lay stormwater pipes at such a shallow gradient. 1:80 would be the minimum I'd look for as it seems be be the lowest slope that a drain will " self clean " without any maintenance necessary post-installation in my experience. Stewie Re: Gradient of underground stormwater pipes 5Jun 18, 2016 12:37 pm You state that there is sufficient fall to the pit (as shown on the plans) but how do you know this is factual and how do you know that the pipes back up? If there is sufficient fall shown on the plans but the pipes back up, this raises alarm bells! Have you had your slab levels confirmed by your independent building consultant? One issue is that the plumber will have signed off his own work. Non compliant stormwater drainage is endemic in Victoria, if the builder doesn't play ball, contact the VBA plumbing dept to arrange an inspection. BTW, you have posted this in the wrong sub forum, it should be under Building Standards; Getting It Right! Just ask a mod to move it. 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: Gradient of underground stormwater pipes 6Jun 19, 2016 12:21 am Thanks Stewie and SaveH20. The drainage plan states that the legal point of discharge is 1100mm beneath the surface in an underground stormwater mains that is accessible by a pit on the street.The pipes back up by 1) opening the inspection openings and 2) seeing the flooding on the other end where it is now pooling on the surface. They started the drainage way too low to begin with. I haven't had slab levels confirmed by the independent consultant but they 'seem about right'. We have plenty of height to work with, however, it looks like they've simply dug them far too low to begin with. I think the VBA may be a next step if the builder doesn't listen to my independent inspector. Shouldn't the builder ask their subcontractor to move it at their cost so the builder doesn't lose out? Where do I ask the mod to move this thread? Re: Gradient of underground stormwater pipes 7Jun 19, 2016 2:46 am It is the plumbers fault and they need to fix it. If they don't, you could ask the VBA to inspect it and if the plumber has already signed off on it, it could prove even more 'embarrassing' to him with the VBA. Wrong slab heights are not uncommon and I was glad to read that the plumber had laid the pipe too deep at the start...certainly much better than having a low slab. It is important to have a slope because bed load barely moves at the best of times and 95% of Melbourne's 'rainfall' is drizzle or light showers, conducive to a gradual build up of crud. To move the thread, just click the red exclamation mark (it is the report button) and leave a message for a mod to move the thread to Building Standards. Good luck with it all. 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: Gradient of underground stormwater pipes 8Jun 20, 2016 5:59 am Thanks for your help. I'm meeting the builder this week and will let you know how it goes. One things for sure, we're not completing and the builder isn't getting their final cheque until this is fixed! Update: spoke to the SS today. Thankfully it was raining and it was very evident that water was backing up in the pipes. The issue seems to be the services (gas and phone) under the nature strip which they went over with the plumbing instead of under. They've agreed to move it under which should rectify the problem. After they do that, they'll get it inspected with a camera to make sure it's clear. They are quite aware of the plumbing commission and the need to meet their standards as it came up in conversation. Things are on the right track. Hopefully we can get it fixed and settle soon. I found my research and being able to have an informed conversation with the SS about plumbing topics, gradient, inspection openings, charged vs not, etc all helped as he realised he couldn't pull the wool over my eyes. I persevered and i think i have a good outcome Re: Gradient of underground stormwater pipes 9Sep 22, 2016 11:31 pm Underground stormwater pipes issues happen to this plumbing company and builder that I think you are using. Is it B... and C...? I have seen their sites where pipes were left not physically connected underground after hand over and personally know the owners. One of them was a show home which had all landscaping done including a driveway but when the owner moved in they had to demolish the driveway to find the pipe wasn't actually present were it was supposed to be. Lucky you spotted the problem earlier. Built a 2 storey house... hebel, proctor, pvc windows, aiphone, deck roofs, louver covered patio Re: Gradient of underground stormwater pipes 10Sep 23, 2016 1:08 pm Yes...the B... plumber is certainly living up to their initials! And yes, C as well. It's really disappointing to see a plumber that can't make water slope in the correct direction and the builder not QA'ing them and holding them to account, but rather trying to convince the customer that all is OK. Re: Gradient of underground stormwater pipes 11Sep 23, 2016 1:34 pm It is wrong and it is recognised as being wrong but plumbers are allowed to sign off on their own work. No one checks. As a measure of plumbing incompetence, approximately half of the current slab heave epidemic plaguing the Melbourne northern and western suburbs have been found to be caused by faulty plumbing. 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Hi JW I just read your post and I find this situation quite strange. When we build, we get a temp pole for construction which becomes the permanent pole for one of the… 1 3934 1 4074 4 5087 |