Water Tank Base

[multiweb]

Hi guys, I thought I'd ask the concreting gurus, obs piers and all.
I'm getting a slimline water tank delivered in a couple of weeks. I want to stick it on the side of my house. The distance between the brick wall and the fence is approx 1.3mm. The water tank base is 800mm wide by a couple of metres long. Capacity is between 1500~2000L so we're talking about 2T of weight full. The concrete I have is about 100mm thick. I'm not sure if it's meshed though, I don't think it is. I was thinking of bricking a 800x2000mm on top of the existing concrete and cement the bricks. May be two rows, level and have the water tank on top of this.
What do you reckon? Good idea or no way? Thanks.

[Barrykgerdes]

That concrete should stand close to 1 tonne per square inch.
Your water tank if mounted flat on the concrete will not add more than a few pounds per square inch. Don't worry

Baz

[Jeffkop]

You gotta luv how you can just put any old question up on this forum and someone will be usually able to answer you ... I've said it before and I 'll say it again ... this forum rocks !!!!:thumbsup::thumbsup:

[Bassnut]

Dont use a brick base at all IMO, I found flat cemented bricks had no strength at all, the cement cracks or seperates from the brick with not much effort.

[CoombellKid]

Sand is good for water tanks, although I've used railway sleepers the real
ones not the ones you get from Bunnings on the size tanks you are
using. If you keep them in the shade you have nice cool water to drink.
If your not used to drinking rain water dont be surprised if you get the
runs first off, this wont last more than a few days.

Cheers,CS

[multiweb]

Thanks Barry - makes sense.

Good point. I'll get a concrete mower and level the slab so it's flat and maximise the contact with the water tank base.

[Dennis]

Hi Marc

Don’t forget the following 2 items:

#1. First flush diverter.
#2. Leaf Eater.

#1 allows the first flush of (dirty) rainwater from the roof to go to waste so that water contaminated with bird poo, roof dust, etc doesn’t end up in your tank to form a sludge.
http://www.rainharvesting.com.au/downpipe_diverter.asp
http://www.enviro-friendly.com/first-flush-diverter.shtml

#2 traps leaves from the roof and gutters, preventing them from entering the pipes that carry the water into the tank.
http://www.enviro-friendly.com/rainhead.shtml

I fitted two First Flush Diverters, one at the roof gutter and one at the tank water entrance and when we empty these after a rainfall event, the 1st one is usually quite mucky with all the sediment from the roof whereas the 2nd one at the tank entrance is relatively clean, but acts as insurance just in case the 1st one is overwhelmed. I fitted a Leaf Eater and it does a great job of preventing leaves from entering the system.

For the base, I used 8 inch treated sleepers to make a framework and filled it with Decomposed Granite and this has supported our 5000 Litre tank without any problems for the 3 years that we have had it.

I also fitted a pump and 3 taps in the garden so we can use the rainwater at mains pressure.

Cheers

Dennis

[CoombellKid]

Those water tank storage folk must love you city slickers :rofl:

[CoombellKid]

I think you'll find birds really dont poo enough to efect you, never
effected me or the hundreds of thousands of aussie bush folk proves.
And the heat of a good days sun is more than enough to sterilise any
dangers a bird poo could cause. I would be more worried about the
polluttion the rain caught coming down through a city sky. A good windy
day is enough to blow the dust.... a roof is wide open to the elements
24/7 weather is a consistant force.

Cheers,CS.... thanks for the giggle.

[Benno18]

Mmmmmm. My roof is supposed to be a red colour. But because we live in a developing estate, all the sand blows around and ends up on the roof giving us a red roof with a tinge of grey in the middle of the tiles. If i had a tank i think the first flush diverter would a good investment, no dirty water coming out.

[Dennis]

I had three long term goals when I installed the tank:

Do it right, once, up front.
Fit and forget.
Preventive Maintenance.

Our neighbour had theirs installed without these devices and within 12 months, had over 10 cms of sludge in the bottom of their tank and the water smelled foul and came out thick with suspended particles.:P

After 3 years, our water doesn’t smell and to the naked eye, looks clear. After a rain fall event, the water trapped in the reservoir of the 1st First Flush diverter looks like someone tipped a bowl full of fine clay or grey powder into the pipe. And, the leaf diverter gets choked with leaves from nearby gum trees in spite of cleaning the gutters on a regular basis.

Net result? More work and expense up front, but leading to more time for astronomy…less time spent maintaining the water tank system! We city slickers aren’t all daft!;)

Oh, and I also fitted anti mosquito mesh to make sure the blighters couldn’t enter the system and breed. Oh, and the water pump filter still looks clean!:)

Cheers

Dennis

[CoombellKid]

I'm not arguing with you, go for it city slicker. You'll rarely see it out in
the bush. Where we've been doing it for literally hundreds of years :P

I think if your getting 10cm of silt in the bottom of your tanks in 12
months even if you dont have the crap you have on yours there is
seriously something else happening :thumbsup: :thumbsup: :thumbsup:. Man, I used to live
next to a road that had logging trucks, cattle trucks (mostly B doubles)
and in five years never saw 1cm of slugg in my tanks and om unsealed
roads. But I suppose if your not used to it and you dont know, you will
buy whatever the salesman will tells you.

Cheers,CS

[Dennis]

Well, from reading your replies at times it does appears that you are arguing or at least being a little condescending! Terms like “city slicker” and “crap” hint at this. What’s more, I did my research on line, observed local installations and purchased the parts based on this – no salesperson “selling” me stuff.:P

Organic debris in the form of bark and leaves from 3 large gum trees often blankets our neighbour’s roof and chokes his gutters. I suspect the sludge comes from these just breaking down into small particles and washing into the tank?:shrug:

The grey sludge in the waste reservoir of our 1st flush diverter I put down to general pollution from living in a large city – it smells too, when we release the waste valve.:eyepop:

We don’t drink the water; it gets used for watering pots, washing the car, windows, etc. Brisbane seems to be a dirty city in terms of air borne pollutants? When we visit either the Sunshine or Gold Coasts, the sea borne air is just so incredibly fresh by comparison.:)

You’re lucky to have relatively clean air to breathe. I once saw a medical program where a Sydney surgeon was operating on a country woman and he was astonished at how clean her lungs were. He indicated that all the city lungs that he had seen were polluted throughout by fine particles.:(

Cheers

Dennis

[Barrykgerdes]

My family drank untreated tank water from the roof for a very long time. They never cleaned the tanks out. I guess that may be why they died in the end. only one of them got a queens telegram the others died in there 90's except my mum who is 98.

Barry

[Dennis]

Sounds like some good longevity genes running in the family. :) My concern is more about long term maintenance issues, as we don’t drink the water.

I’ll probably leave it at that, to avoid drifting too far off topic from Marc’s original post.;)

Cheers

Dennis

[Phoenix]

Hi Marc

I would agree with Baz that your existing concrete slab should be fine - but it would probably pay to lay some good quality evenly spaced sleepers (about 75mm depth) on your concrete slab as CS suggests before placement of your tank on top - too easy. If you worried about rubbish blowing in between/under the sleepers (or perhaps for a cleaner look) the alternative would be to use the sleepers to make an open box that sits on top of your slab then fill it with compacted quarry rubble before placement of your tank on top.

Dennis, like your set-up. From one city slicker to another - I have 4 huge significant river reds in my front yard and 1 in the back, all of which dump so much rubbish on my roof (not to mention the two families of possums we have), I simply can no longer use my water tank. Short of removing these trees, I don't need a sales person to tell me I need to take some preventative measures similar to yours - depends on the potential contaminates in your local area, no matter where you live :thumbsup:.

Clear skies and tanks to all

Cheers

[multiweb]

Hey thanks for the tips Steve & Dennis. Better idea to level than mowing the concrete. That's a mean installation you got Dennis. Very cool. :thumbsup:

[Dennis]

Hi Marc

The 10kms of underground pipe were necessary to route the inlet pipe from the drain to the tank, and the tank overflow/return pipe back to the drain, as this is a walk way.

We could have run the inlet pipe from the gutter down pipe directly to the tank inlet without it being a hazard, but then the return pipe back to the drain would have been too low, forcing people to duck (or bang their head) if they walked along the path.:(

And of course, this was the only place the 5000 Litre tank would fit!:rolleyes:

Cheers

Dennis

[multiweb]

Yeah you've given me a lot to think about. Thanks heaps. :thumbsup: I don't want to have to re-visit the installation later on and you've nicely pointed all the things that can be prevented.

[Dennis]

Hi Marc

I don’t know what your local environment is like, but I need to get on the roof 3 to 4 times each year to clear the gutters and down pipe exit holes, mainly of organic debris from 3 very large gum trees on our neighbours fence line. We also have a population of some 30-40 crested pigeons in the area and they just love sitting on the TV aerial and pooing on the roof. We only have the one non-resident possum which lands on the roof every night, just passing through on his way to his feeding grounds.

I usually find three “layers” of stuff in the gutters:

Strips of bark and whole gum leaves
Crumbled bark and gum leaf fragments broken down into smaller pieces from ageing.
Sludge which might be a combination of well broken down organic material and general air borne matter.

This stuff gets channelled by the rain and collects near the down pipe exit holes and whilst it doesn’t always completely block them, it can greatly reduce the flow rate of escaping rain water and thus requires scooping out regularly, otherwise rain just floods over the edges of the guttering.

The Leaf Eater is very effective at catching and shedding the bark strips and large leaves from the roof and gutters, via the (upper) 45 degree angled large pitch mesh. The actual entry point for water into the Leaf Eater chamber also has a secondary, (removable) smaller pitch mesh filter and this collects the smaller debris and sludge that gets through the larger pitch 45 degree mesh.

The First Flush Diverter then catches the smaller particles and sediments that make it thus far. In theory, this sediment-laden, first flush water “should” trickle out of a small hole, via gravity, to waste. Unfortunately, this hole easily blocks up with sediment after every 3 or 4 rain events so I need to manually empty the waste and clean the exit hole in the rubber washer.

This is why I fitted an additional (2nd) First Flush Diverter at the tank. If we are away on holidays and the 1st First Flush Diverter clogs up, then the under ground pipes and the 2nd unit should catch most of the sludge before it gets into the tank. A 2.4m length of 4inch diameter PVC pipe forms the waste chambers of our First Flush Diverters, their volume calculated for the size of the collecting area of our roof versus the volume required to divert to waste.

I suspect that if you don’t have any leaves falling into your gutters or onto the roof, then there may be less need for these devices although once fitted, they do give you peace of mind - a sort of belt and braces approach!

In terms of maintenance, this is what I do:

After every rain event, brush off the loose leaves/bark that collects on the top of the coarse 45 degree mesh of the Leaf Diverter.
Every 2 to 3 months, remove and clean the smaller pitch mesh filter in the Leaf Diverter – it gradually chokes from the finer particles and sludge.
Every 2-3 months, check the drip-to-waste points of the First Flush Diverters to make sure the contaminated water has escaped prior to the next rain event.

After collecting 3 or 4 carrier bags of leaves and bark each time I climbed on the roof, it really was a no-brainer to fit the Leaf Eater!:)

Good luck!

Cheers

Dennis

[multiweb]

Mate I can't thank you enough. Thanks for taking the time to spec it all out. You've saved me hours/days of research. I printed all your stuff and that's certainly given me a lot to think about. :thumbsup:

And thanks to everybody else for the slab tips.

[Dennis]

No worries Marc glad it was useful.:)

Just make sure you factor in the requirements for your own environment as they will probably vary from mine. Also, I am not an expert on the subject so although my observations of what I see on our roof and in our gutters are accurate, my interpretation of how to deal with these and how I have implemented my design may not be optimal, although so far it has worked for us!

Cheers

Dennis

[Lumen Miner]

Whats wrong with the ones from Bunnings?? :rofl: I take it you mean the wet H4 treated pine sleepers. Some stores still sell the hardwood ones, they would be ok, but I agree the pine ones are a bit shody. :)