Hi all
I wondered if anyone had any views or experience of extending an existing pond.
I currently have a 4Kgal pond of conventional build (concrete base, block and brick double skinned walls, 2 1/2-3 feet out of the ground, 5 ft deep) which I was thinking of extending to 6Kgal. I was thinking of taking out an end wall, laying a concrete base to cover the additional area and extending the walls.
Issues I was wondering about were;
Will leaving the pond empty whilst work is done make it vulnerable to sideways ground pressure.
Is there any way of ensuring the structural integrity of the old and new bases or would I have to break up the existing base and start again.
Is it possible to extend the existing walls without creating an ineherent structural weakness.
Would it just be far simpler to build a new pond.
Any thoughts welcome.
Regards
Jon W
Extending an existing pond
Moderators: B.Scott, vippymini, Gazza, Manky Sanke
Hi Gazza
Thought you might say that! I know really that it is the best approach but the thought of all the extra work in breaking up the existing one doesn't excite me.
I've been wrestling with a bacterial/viral problem that has been plaguing my pond. I've lost over half of my fish and am still not entirely sure what caused it. Definitely not KHV because the temperature was too low (5-7C). I've decided not to restock until the whole thing has been radically overhauled or a new pond built.
The one good thing is that I've now got a proper 300 gal hospital/quarantine tank up and running so any future purchases will be qt'ed/heat ramped in the correct manner.
I'm just about to start on the indoor growing on pond; again! Just got 2 tons of broken up concrete to shift from the previous debacle. Weather permitting I should be able to that and start work on shuttering for a base this weekend.
Cheers
Jon
Thought you might say that! I know really that it is the best approach but the thought of all the extra work in breaking up the existing one doesn't excite me.
I've been wrestling with a bacterial/viral problem that has been plaguing my pond. I've lost over half of my fish and am still not entirely sure what caused it. Definitely not KHV because the temperature was too low (5-7C). I've decided not to restock until the whole thing has been radically overhauled or a new pond built.
The one good thing is that I've now got a proper 300 gal hospital/quarantine tank up and running so any future purchases will be qt'ed/heat ramped in the correct manner.
I'm just about to start on the indoor growing on pond; again! Just got 2 tons of broken up concrete to shift from the previous debacle. Weather permitting I should be able to that and start work on shuttering for a base this weekend.
Cheers
Jon
Hi Jon
Good to hear that you are still around!!
have to agree with Gazza, no suprise!
Was not one of the "problems" with the existing pond was that it was sited in a very exposed position which restricted your temps in summer?
Good luck with QT base MKII, guess you will be mixing the muck yourself!!
Regards
Dave
Good to hear that you are still around!!
have to agree with Gazza, no suprise!
Was not one of the "problems" with the existing pond was that it was sited in a very exposed position which restricted your temps in summer?
Good luck with QT base MKII, guess you will be mixing the muck yourself!!
Regards
Dave
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Gazza
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Hi Jon,
Great to hear your still cracking on with things and i am sure the new QT will be up and running in no time
I think one of the problems with extending a pond is getting the base spot on as i believe ( and i am no structural engineer) they have to be 100% spot on the same or you could get movement differences.
Hopefully one of our cleaver people may be able to help.
Great to hear your still cracking on with things and i am sure the new QT will be up and running in no time
I think one of the problems with extending a pond is getting the base spot on as i believe ( and i am no structural engineer) they have to be 100% spot on the same or you could get movement differences.
Hopefully one of our cleaver people may be able to help.
Another option might be to build a separate pond of about 2,000 gallons and then link the two via the filtration system and pipework. Or build it slightly higher and have a large water fall flowing into the main pond. There would a issues about getting the water flow right and it wouldn't give your fish more swimming space, but would save you re-building the whole pond and you'd be able to build the extra pond while your current one was running normally. You'd still get the advantage of the extra water volume too.
Hi Dave
I've been around all the time; I just have had much to say recently! Your right about the existing pond, low temp (never higher than 17C last year) is a problem; it's too shaded - house on one side and windbreak of tall trees on the other side. My only other viable site for another pond is really exposed and on a steep hill. Therefore the only reaslistic options are to break up the existing pond and start again or extend it.
I'm going to get ready mix in for the base of the growing pond. Rather than just concrete where the base of the pond is going, I was going to concrete the filter area as well. I don't fancy mixing it all by hand, especially after last time!
Hi Gazza
I hadn't thought of that - I suppose that unless they are exactly the same thickness they will have differential rates of expansion. My thought was that the pressure of water on a base with seam might turn it into a miniature version of that new exhibit in the Tate Modern.
Hi Eds
It's a good idea (would also mean your growers have the same water conditions as the main pond) but as I'm just embarking on a small pond indoors so I don't know if I would want a second one next to the main pond. I was thinking more along the lines of increasing the swimming space in the main pond.
Cheers
Jon
I've been around all the time; I just have had much to say recently! Your right about the existing pond, low temp (never higher than 17C last year) is a problem; it's too shaded - house on one side and windbreak of tall trees on the other side. My only other viable site for another pond is really exposed and on a steep hill. Therefore the only reaslistic options are to break up the existing pond and start again or extend it.
I'm going to get ready mix in for the base of the growing pond. Rather than just concrete where the base of the pond is going, I was going to concrete the filter area as well. I don't fancy mixing it all by hand, especially after last time!
Hi Gazza
I hadn't thought of that - I suppose that unless they are exactly the same thickness they will have differential rates of expansion. My thought was that the pressure of water on a base with seam might turn it into a miniature version of that new exhibit in the Tate Modern.
Hi Eds
It's a good idea (would also mean your growers have the same water conditions as the main pond) but as I'm just embarking on a small pond indoors so I don't know if I would want a second one next to the main pond. I was thinking more along the lines of increasing the swimming space in the main pond.
Cheers
Jon
hi
im no expert but about fifteen years ago when i got into koi.in my garden was an concrete fish pond level with ground.
what i done was to knock one end wall down extend the side walls by 4ft in length.
the base to the extension was made lower than original base by 10 inches(dont know why),a bottom drain was put in .the sides and ends were all shuttered up to ground level.
next was a concrete collar put round old part of pond then three rows of hollow blocks used to bring new pond size upto 4ft in depth.
a bit of diy rendering then painted with p1 paint
fifteen years later no leaks to report
with regards to water quality crystal clear,i get a little bit of crap on btm furthest away from drain ,nothing a few scoops of the net or hoover will sort out.
finished pond size is 12ftx6ftx4ft at deepest end.not a huge pond but nice.
so it can be done.
darren
im no expert but about fifteen years ago when i got into koi.in my garden was an concrete fish pond level with ground.
what i done was to knock one end wall down extend the side walls by 4ft in length.
the base to the extension was made lower than original base by 10 inches(dont know why),a bottom drain was put in .the sides and ends were all shuttered up to ground level.
next was a concrete collar put round old part of pond then three rows of hollow blocks used to bring new pond size upto 4ft in depth.
a bit of diy rendering then painted with p1 paint
fifteen years later no leaks to report
with regards to water quality crystal clear,i get a little bit of crap on btm furthest away from drain ,nothing a few scoops of the net or hoover will sort out.
finished pond size is 12ftx6ftx4ft at deepest end.not a huge pond but nice.
so it can be done.
darren
Hi Jon
Think Gazza was talking about potential differential movement between new pond base and existing base. Us lucky Essex lads with lovely clay can get a lot of ground movement with clay shrinking as it drys (desicates) and expanding as it wets so subsidence and heave are issues when considering pond construction, doesn't matter too much if the base is one solid raft supporting the walls as when it moves so will they.
If the new base isn't tied into the existing you could get a split along the join, certainly on clay subsoil. Suspect your ground is a lot less plastic than ours but this is the main risk of extending.
Regards
Dave
Think Gazza was talking about potential differential movement between new pond base and existing base. Us lucky Essex lads with lovely clay can get a lot of ground movement with clay shrinking as it drys (desicates) and expanding as it wets so subsidence and heave are issues when considering pond construction, doesn't matter too much if the base is one solid raft supporting the walls as when it moves so will they.
If the new base isn't tied into the existing you could get a split along the join, certainly on clay subsoil. Suspect your ground is a lot less plastic than ours but this is the main risk of extending.
Regards
Dave
Hi Dave
Clay; that brings back memories - lived on a hill in SE London for a long time; for added excitement we had an enormous tree at the bottom of a very small garden which couldn't be touched. Still the house only had to be underpinned once!
Here in Wales, dig away the subsoil a couple of inches and you hit red sandstone. Very stable but not a lot of fun to dig.
In terms of tying-in, I wonder if inserting horizontal rods into the existing base that extend into the new base would provide sufficient integrity to hold the whole thing together if there was movement? I'll try to find out.
Thanks very much for the thought.
Regards
Jon
Clay; that brings back memories - lived on a hill in SE London for a long time; for added excitement we had an enormous tree at the bottom of a very small garden which couldn't be touched. Still the house only had to be underpinned once!
Here in Wales, dig away the subsoil a couple of inches and you hit red sandstone. Very stable but not a lot of fun to dig.
In terms of tying-in, I wonder if inserting horizontal rods into the existing base that extend into the new base would provide sufficient integrity to hold the whole thing together if there was movement? I'll try to find out.
Thanks very much for the thought.
Regards
Jon
Hi Jon
Would Darran's idea not be worth thinking about, if you made the new part of the pond deeper than the exsisting pond then use the really heavy concrete blocks up to the exsisting pond base, it might work. Like Gazza no expert here but if you built a pond with 2 differant levels it would have the same forces behind it so this may work.
Good luck with whatever you choose to do
Would Darran's idea not be worth thinking about, if you made the new part of the pond deeper than the exsisting pond then use the really heavy concrete blocks up to the exsisting pond base, it might work. Like Gazza no expert here but if you built a pond with 2 differant levels it would have the same forces behind it so this may work.
Good luck with whatever you choose to do
Hi Kimr/Darren
For some reason I couldn't see Darren's post last night. I wouldn't have a problem with a 2 level base. I think if I used hollows with reinforcing rods for the wall between the 2 base levels. I think I would go down another foot so that the new base would be six foot deep, I would also add another bottom drain so no problems with crud accumulation.
Thanks for that. I had become so fixated on matching 2 bases at the same level that I hadn't thought of 2 bases as the solutions.
Cheers
Jon
For some reason I couldn't see Darren's post last night. I wouldn't have a problem with a 2 level base. I think if I used hollows with reinforcing rods for the wall between the 2 base levels. I think I would go down another foot so that the new base would be six foot deep, I would also add another bottom drain so no problems with crud accumulation.
Thanks for that. I had become so fixated on matching 2 bases at the same level that I hadn't thought of 2 bases as the solutions.
Cheers
Jon
Hi Jon
I took out the longest wall on my 2'6" deep pond and extended it with the new base at just over 4' Because the original pond liner was only on sand and I didn't want to disturb the footing on the removed wall, I built up a single wall off the new base then removed the sand to below the footing and then concreted the old sand base encasing the existing footing (if you know what I mean). The side walls are easily extended with the extenders used for house extensions. The pictures below may help. Pond was then polyurethane foamed and glassed.
Shaun
I took out the longest wall on my 2'6" deep pond and extended it with the new base at just over 4' Because the original pond liner was only on sand and I didn't want to disturb the footing on the removed wall, I built up a single wall off the new base then removed the sand to below the footing and then concreted the old sand base encasing the existing footing (if you know what I mean). The side walls are easily extended with the extenders used for house extensions. The pictures below may help. Pond was then polyurethane foamed and glassed.
Shaun
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