Browse Forums Eco Living 1 Nov 06, 2012 8:53 am Could anyone comment on the base our rainwater tank is sitting on. Our plans specify a compacted sand base but this looks pretty unsandy to me at least on one side. According to the building designer and the builder the sand "was stabilised with cement so it will provide a stable surface". What does stabilising sand with cement mean?
Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Re: What should a rainwater tank sit on? 2Nov 06, 2012 9:35 am Stabilised sand is sand with 5% cement mixed in so it sets hard, but not as hard as concrete. It looks like you have some soil on the top of the base. 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: What should a rainwater tank sit on? 3Nov 06, 2012 10:55 am Hi Bashworth. Thanks for the reply. I have checked the height of the tank against the specifications and it would seem that our tank is buried about 13 centimetres. How wide should the base be though? Should it be just to the diameter of the tank or should it extend out a bit? The builder and the building designer have also told us that the stability of the tank is "subject to the stability of the soil below which will need to be paved with fall away from the house." If we put concrete around the tank what do we do if the tank needs removing or repairing? It seems to me that putting it on sand may not have been a very useful option if we are on clay soil and need to pave around it.
Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Re: What should a rainwater tank sit on? 4Nov 06, 2012 12:46 pm I often site poly tanks on a compacted sand base. The base is dug in and is usually about 100 mm wider on all side than the tank. The sand is compacted, then wetted and later compacted again before the tank is moved into place. Sand then fills the gap between the tank and the soil, the sand covered over and the tank usually sits about 80 mm down. It looks neat and there has never been any stability or other issues but it must be done correctly. It is often done to fit a taller tank. Looking at the photos, I have concerns. Why is the plastic there? It looks amateurish. The tank is much too close to the wall!!! Also, do/did you have a termite barrier? The first photo shows that the ball valve outlet that supplies the tank is underground!!! If you intended to pave around the tank, then ethically they should given you the option to upgrade your building plans to have it sited on a concrete slab. The tank looks to be about 1,500 litres. This is very small. Was it required as per your State's building code and what State are you in? Does your council permit water tanks to be so close to the wall? This installation reeks of incompetence and I can smell it from here. I would have everything redone and site it on a slab. It will be easier to do it now rather than later but I wouldn't trust these cowboys. 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: What should a rainwater tank sit on? 5Nov 06, 2012 1:50 pm Thanks once again for the reply H2O. I will investigate the siting of the tank. We were supposed to have a 3500 litre tank but this was downgraded to 2500litre because the other one wouldn't fit - too wide. This was decided between the builder and the building designer who drew up the plans and did the contract administration. It is not so much that we were intending to pave but because we are on clay soil we have been told to pave. I don't think the building designer took any note of the sort of soil we were on when she did the plans and only provided for it to be put on a compacted sand base. I don't believe we even have that. And yes - we have a termite barrier. Re: What should a rainwater tank sit on? 6Nov 06, 2012 4:05 pm I am concerned that the installation may have breached the barrier. I would have installed two smaller tanks rather than one. By doing this, they could have been linked and used as a settling system so that the pump drew from the best quality water. I would not have sited them outside a window. 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. 18 74677 DIY, Home Maintenance & Repair But if it is a ground level open pit, then it is not a charged system. No surprises there. The pipes have obviously been altered and there would be a reason for this.… 3 25115 Grate, thank you! RexChan if thats the reason i could sleep well without thinking about additional cost. But 1st i'll need to read about NRV cleaning/replaing stuff. I… 7 25436 |