Hi Jon
If you are putting in a pad on the existing floor then can’t see you would need 9â€Â
Possibly stupid question about concrete
Moderators: B.Scott, vippymini, Gazza, Manky Sanke
Hi DaveJ and Gazza
I guess depth will be decided by pipe diameter? Is there a rule for depth of concrete either side of the pipe. I was thinking of single 4" bottom drain or is that a bit over the top. I would have thought I would then need at least 7"-8".
And, I should be able to knock it up myself? My next door neighbour's offered me the loan of a mixer and his son is a builders apprentice so I can get some help if needed.
I'm not sure how deep the current floor is; I reckon it must be reasonably sound - it's been there a long time with no signs of fatigue. I wondered if I should build the pad a little longer and wider than the dimensions of the tank to spread the load further just in case the existing floor isn't as thick as I hope (might dig a borehole outside to check).
Is there any need to prepare the existing floor in any way(similar to a bonding coat of plaster - PVAing brickwork to prevent it sucking all the water out of the plaster and crazing the surface). I wondered if there should be some sort of surface sealer or plastic layer.
I also wondered if I should use rebar, REIN fibres or a specific concrete mix. I know it won't have the same load bearing requirements as a 6' deep outdoor effort but want to be sure that it is structurally sound.
The other thing I wonder is how on earth to secure formwork. All I can think of is to fix into the floor then securing the formwork to the battens to prevent bowing or seepage.
Sorry if I'm asking lots of what might seem obvious questions. I've done lots of d.i.y. but nothing particularly structural. I've also tried looking all this up on the internet but most advice seems to be for creating a pad for sticking a shed up. I know people around here will offer advice but their experience of building liquid retaining structures is slightly different - slurry pits! These are built entirely from formed concrete and rebar.
Thanks for all your help.
Jon W.
I guess depth will be decided by pipe diameter? Is there a rule for depth of concrete either side of the pipe. I was thinking of single 4" bottom drain or is that a bit over the top. I would have thought I would then need at least 7"-8".
And, I should be able to knock it up myself? My next door neighbour's offered me the loan of a mixer and his son is a builders apprentice so I can get some help if needed.
I'm not sure how deep the current floor is; I reckon it must be reasonably sound - it's been there a long time with no signs of fatigue. I wondered if I should build the pad a little longer and wider than the dimensions of the tank to spread the load further just in case the existing floor isn't as thick as I hope (might dig a borehole outside to check).
Is there any need to prepare the existing floor in any way(similar to a bonding coat of plaster - PVAing brickwork to prevent it sucking all the water out of the plaster and crazing the surface). I wondered if there should be some sort of surface sealer or plastic layer.
I also wondered if I should use rebar, REIN fibres or a specific concrete mix. I know it won't have the same load bearing requirements as a 6' deep outdoor effort but want to be sure that it is structurally sound.
The other thing I wonder is how on earth to secure formwork. All I can think of is to fix into the floor then securing the formwork to the battens to prevent bowing or seepage.
Sorry if I'm asking lots of what might seem obvious questions. I've done lots of d.i.y. but nothing particularly structural. I've also tried looking all this up on the internet but most advice seems to be for creating a pad for sticking a shed up. I know people around here will offer advice but their experience of building liquid retaining structures is slightly different - slurry pits! These are built entirely from formed concrete and rebar.
Thanks for all your help.
Jon W.
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deggsymann
- Sandbar shark
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- Location: derbyshire
Hi JonOne thing I wondered. If you line the pond with Kingspan how do you sort out nice round corners
I didn't use Kingspan, but a 1" Polyurethane board on my main pond which is as near as dammit the same thing for me to be able to answer your question.
To get the corners i cut a length about 4" wide and then using a decent saw chamfered it to a 45 degree angle. Looked a bit like this in cross section /___\ (crap drawing, but you should get the general idea).
Then it was siliconed into place, to form a 45 degree corner. Ran a bead of silicone up the joint and smoothed it to stop any gaps. Because of the angle of cut, there was hardly any void behind the foam in my case, but i suppose you could always backfill with fine sand etc. I then put a small triangle of foam in the gap at the top to help the glasser go over the top a few inches, as i knew the coping stones would show a small bit of the corner. Once this is glassed it is as strong as any other part of the pond, and the angle was no trouble at all for the glasser to do.
The pics might help show it a bit better than i can describe.
[img]http://www.koivista.com/files/deggsymann/6327_DSCF00109.jpg[/img]
[img]http://www.koivista.com/files/deggsymann/6453_DSCF0117.jpg[/img]
Hi Deggsymann
Thanks very much for the pics. I was wondering how to avoid "sharp" corners when using foam rather than render for the interior lining. Doesn't look too difficult (famous last words!). Did you do your own glassing? This is something I was wondering whether I should tackle myself on the growing on pond as a sampler for whether to attempt on a larger outdoor job.
My main concern is at the moment is how to lay a concrete pad on an existing concrete floor as you can see from comments in the previous post.
Cheers
Jon W.
Thanks very much for the pics. I was wondering how to avoid "sharp" corners when using foam rather than render for the interior lining. Doesn't look too difficult (famous last words!). Did you do your own glassing? This is something I was wondering whether I should tackle myself on the growing on pond as a sampler for whether to attempt on a larger outdoor job.
My main concern is at the moment is how to lay a concrete pad on an existing concrete floor as you can see from comments in the previous post.
Cheers
Jon W.
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Gazza
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Hi Jon,
You keep asking away mate and don't forget some pictures once it all starts
I would build a solid timber frame and secure it in position where the new pond is going to be.You could make this out of some strong timbers and then fix some plywood inside at the hight you need and make it square so you can pull a straight edge across the wood to make the base nice and flat. You can then lay a plastic membrane down (visquine) not to sure on the spelling which will keep all base nice and dry.
I would make the base the size you require for the pond and also the filter area so its all at the same level for your equipment.
I suppose depending on what blocks you use you could even set them in the base ready for building,but not being a builder i am not 100% sure on the best way
You keep asking away mate and don't forget some pictures once it all starts
I would build a solid timber frame and secure it in position where the new pond is going to be.You could make this out of some strong timbers and then fix some plywood inside at the hight you need and make it square so you can pull a straight edge across the wood to make the base nice and flat. You can then lay a plastic membrane down (visquine) not to sure on the spelling which will keep all base nice and dry.
I would make the base the size you require for the pond and also the filter area so its all at the same level for your equipment.
I suppose depending on what blocks you use you could even set them in the base ready for building,but not being a builder i am not 100% sure on the best way
Hi Gazza
Whatever method used to create the formwork, the biggest headache will be ensuring that a truly flat base re. contours in the existing floor.
I hadn't thought of using plywood as formwork. The only issue would be ensuring that it is cut accurately to ensure that it is square.
Does the visquine lie underneath or on top of the base?
I'm still not sure how deep re. the size of the bottom drain pipework. Would 2" inches either side be suffice e.g. 4" drain = 8" base ?
Cheers
Jon W.
Whatever method used to create the formwork, the biggest headache will be ensuring that a truly flat base re. contours in the existing floor.
I hadn't thought of using plywood as formwork. The only issue would be ensuring that it is cut accurately to ensure that it is square.
Does the visquine lie underneath or on top of the base?
I'm still not sure how deep re. the size of the bottom drain pipework. Would 2" inches either side be suffice e.g. 4" drain = 8" base ?
Cheers
Jon W.
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Gazza
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Hi Jon,
Do you mean making sure the base is flat
You could cut out the wood so tits oversize and make a frame then using a level mark round the wood and cut it of level then you know the base would be squsre..... i think
You lay the visqueen on the bottom of the base and pour the cement on the top this is also a good way to build a pond as it stops any ingress of water.
http://www.visqueenbuilding.co.uk/product_d ... 88&sid=146
I would thing a few inches over the top should be OK and if you get hold of a 4" BD you will see the depth from the pipe to the top of the base of the BD isn't really that much.
Here a couple of pictures one shows the base of my pond before and after and one of a BD so you can see the depth,hope this helps.
[img]http://www.koipix.com/gallery/albums/userpi ... 2_1270.jpg[/img]
[img]http://www.koipix.com/gallery/albums/userpi ... 2_1289.jpg[/img]
[img]http://www.koipix.com/gallery/albums/userpi ... 0Drain.jpg[/img]
Do you mean making sure the base is flat
You could cut out the wood so tits oversize and make a frame then using a level mark round the wood and cut it of level then you know the base would be squsre..... i think
You lay the visqueen on the bottom of the base and pour the cement on the top this is also a good way to build a pond as it stops any ingress of water.
http://www.visqueenbuilding.co.uk/product_d ... 88&sid=146
I would thing a few inches over the top should be OK and if you get hold of a 4" BD you will see the depth from the pipe to the top of the base of the BD isn't really that much.
Here a couple of pictures one shows the base of my pond before and after and one of a BD so you can see the depth,hope this helps.
[img]http://www.koipix.com/gallery/albums/userpi ... 2_1270.jpg[/img]
[img]http://www.koipix.com/gallery/albums/userpi ... 2_1289.jpg[/img]
[img]http://www.koipix.com/gallery/albums/userpi ... 0Drain.jpg[/img]
Hi Gazza
What I didn't explain very well is that the existing concrete floor is not 100% flat; I will have to contour the formwork so that when the base is poured it is completely level. The alternative would be a sloping pond. Novel, but not entirely practical!
The only alternative is that I can think of would be to lay the formwork on a bed of mortar and tap it until it is completely level, wait for it to dry, then pour the concrete - don't know if this is practical.
Looking at you piccies it only looks about 1" of concrete overlaying the pipe. I thought it would require much more. That has allayed my fears a bit - started to get visions of using a Kangyo to dig a trench in the floor to accomodate the bottom drain.
The Visqueen goes underneath - cheers.
I notice you have rebar - do you think that is necessary on a 1000 gallons ? I was wondering if I should add rein fibres?
Cheers
Jon W.
What I didn't explain very well is that the existing concrete floor is not 100% flat; I will have to contour the formwork so that when the base is poured it is completely level. The alternative would be a sloping pond. Novel, but not entirely practical!
The only alternative is that I can think of would be to lay the formwork on a bed of mortar and tap it until it is completely level, wait for it to dry, then pour the concrete - don't know if this is practical.
Looking at you piccies it only looks about 1" of concrete overlaying the pipe. I thought it would require much more. That has allayed my fears a bit - started to get visions of using a Kangyo to dig a trench in the floor to accomodate the bottom drain.
The Visqueen goes underneath - cheers.
I notice you have rebar - do you think that is necessary on a 1000 gallons ? I was wondering if I should add rein fibres?
Cheers
Jon W.
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vippymini
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to add a little to your pond base design would be to slope all the bottom towards the bottom drain, keeping the edges flat and square..
so as long as the woodern form/frame is all flat and approx 2-3 inches above the top of the bottom drain you should be fine to shape the base.
or you can build a flat base and add the slopes later.
so as long as the woodern form/frame is all flat and approx 2-3 inches above the top of the bottom drain you should be fine to shape the base.
or you can build a flat base and add the slopes later.
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Gazza
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Hi Jon,
Could you not fit the frame to the floor and then level of the top as i would think once the frame was in and then the visqeen it should be OK...well i think
How about laying blocks round the edge to help hold the frame and visqeen in place while the base is drying
i wouldn't think you need the re-bar.
How are you having the BD and what filtration
Could you not fit the frame to the floor and then level of the top as i would think once the frame was in and then the visqeen it should be OK...well i think
How about laying blocks round the edge to help hold the frame and visqeen in place while the base is drying
i wouldn't think you need the re-bar.
How are you having the BD and what filtration
Hi All
I was thinking about keeping the base flat other than having a slight recess around the BD. I thought that with a pond this small the most important thing for solids removal would be flow.
Laying a course of blocks first does have an appeal. I would then have the option of building another course on top or having a step with the first row above base height within the perimeter of the concrete. Incidentally, I'm still not sure what type of blocks would be best - solid 18"x9"x4" built "upright"?
I'm not 100% sure about where to locate the bottom drain. I have some notion of it being towards one end with 2 filter returns directed towards it, thus creating a reasonable current which would help exercise the inhabitants and facilitate waste removal.
Initially I think the filtration is going to be DIY chambers with static and dyamic K1. I would have used a Nexus POD but have been put off from what I have read here and elsewhere. I'm also persuaded of using a Bakki Shower with BHM, although given all else I have going on this might be phase 2. Initially I'm only planning to house a few "growers" from the outside pond so there won't be a massive bio load.
Thanks for all the advice.
Regards
Jon W.
I was thinking about keeping the base flat other than having a slight recess around the BD. I thought that with a pond this small the most important thing for solids removal would be flow.
Laying a course of blocks first does have an appeal. I would then have the option of building another course on top or having a step with the first row above base height within the perimeter of the concrete. Incidentally, I'm still not sure what type of blocks would be best - solid 18"x9"x4" built "upright"?
I'm not 100% sure about where to locate the bottom drain. I have some notion of it being towards one end with 2 filter returns directed towards it, thus creating a reasonable current which would help exercise the inhabitants and facilitate waste removal.
Initially I think the filtration is going to be DIY chambers with static and dyamic K1. I would have used a Nexus POD but have been put off from what I have read here and elsewhere. I'm also persuaded of using a Bakki Shower with BHM, although given all else I have going on this might be phase 2. Initially I'm only planning to house a few "growers" from the outside pond so there won't be a massive bio load.
Thanks for all the advice.
Regards
Jon W.
Hi Jon
Think that laying the first course of blocks is the best idea to get the outline before filling with concrete, I went with single skin dense blocks on my 1000 gallon tank. May be you could lay the first course flat, will give you close to the bottom drain height?
On a tank of the size you are talking of a flat base will IMHO suffice, go for an airated BD - with 40L/min mine pulls in all the muck, if I leave the air off for a day you can see the muck!
Filtration; up to you; but if I were doing another inside tank I would be seriously tempted to go for a simple vortex and Bakki - Pod or static KI vortex and barrel of fluidised K1 does do an excellent job though.
Keep the research going and get it right first time!
Regards
Dave
Think that laying the first course of blocks is the best idea to get the outline before filling with concrete, I went with single skin dense blocks on my 1000 gallon tank. May be you could lay the first course flat, will give you close to the bottom drain height?
On a tank of the size you are talking of a flat base will IMHO suffice, go for an airated BD - with 40L/min mine pulls in all the muck, if I leave the air off for a day you can see the muck!
Filtration; up to you; but if I were doing another inside tank I would be seriously tempted to go for a simple vortex and Bakki - Pod or static KI vortex and barrel of fluidised K1 does do an excellent job though.
Keep the research going and get it right first time!
Regards
Dave
Hi DaveJ
Maybe I should use 2 rows of blocks side on - that would definitely ensure coverage of the bottom drain and provide additional support where it is most needed.
Do you have any views on the exact location of the BD? I thought filter returns at one end and the BD at the other.
In terms of initial filtration system, I will go static/dynamic K1 - I've got a number of containers lying about collecting rainwater and breeding mossies that could make a decent system. Longer term I definitely agree re. Bakki shower - I've read lots here and elsewhere about BHM and am convinced of their efficacy if not the science of how it works. I'm trying to keep costs down at the moment because of spring outdoor pond build, so I will initially diy as much as I can.
I there is anything else you think I should consider let me know. One thing I'm still not sure about is the concretet mix. Once I've cleared the shed out (a horrible and mammoth job) I am going to start.
Cheers
Jon W>
Maybe I should use 2 rows of blocks side on - that would definitely ensure coverage of the bottom drain and provide additional support where it is most needed.
Do you have any views on the exact location of the BD? I thought filter returns at one end and the BD at the other.
In terms of initial filtration system, I will go static/dynamic K1 - I've got a number of containers lying about collecting rainwater and breeding mossies that could make a decent system. Longer term I definitely agree re. Bakki shower - I've read lots here and elsewhere about BHM and am convinced of their efficacy if not the science of how it works. I'm trying to keep costs down at the moment because of spring outdoor pond build, so I will initially diy as much as I can.
I there is anything else you think I should consider let me know. One thing I'm still not sure about is the concretet mix. Once I've cleared the shed out (a horrible and mammoth job) I am going to start.
Cheers
Jon W>