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Posted: Thu May 07, 2020 2:25 pm
by Ian-M
Hi there - I'm building a fairly large heart-shaped pond with my son - will post a pic if I can. It's on gently sloping ground, about 18 foot wide and 18 foot long by 2-3 foot deep. I intend to put a c 50mm deep concrete collar around the edge to put the liner over, before putting slabs on top. We're digging this out by hand, and have pretty much dug the hole already.
Due to the slope, I've had to build up the ground levels around much of the pond.
Few questions:
- I was planning a 100m sub-base under the concrete collar. Should I whack the freshly-piled soil down before laying the sub-base to make sure the collar doesn't sink (disastrous for the pond) or do you think it will be OK if I just tamp it down firmly? I'm worried that this newly raised ground is going to settle.
- Is my sub-base + concrete solution sufficient? Maybe I do a thicker concrete collar and/or sub base around those parts of the pond edge I've really had to raise - to make sure I'm getting into the original dirt level?
- What slabs do you suggest? I think standard ones wont look good around the top of the heart (non pond-facing edge) as they will splay out. I was thinking a round patio slab 'pack' together with matching standard square/rectangular flags for the straighter heart edges. Ideally the slabs will protude 1" over the pond to protect the liner from UV rays. I'd prefer to use setts but I dont think they'll make sense as a pond edging. And I would be rubbish at trying to cut slabs so that's out too.
I hope this all makes sense. Thanks for any thoughts or comments (apart from about the pond shape 
)
Posted: Fri May 08, 2020 5:50 pm
by Ian-M
Hopefully you can see it here
https://ianm.imgbb.com/
(sorry couldn't upload direct - think because it was a secure server?)
Posted: Thu May 14, 2020 2:04 pm
by Tony McC
The bit that made me sit up was the quote about "whack(ing) freshly piled soil" - you should not be backfilling with soil at all. It wil probably contain bio-degradable organic matter and it's far too difficult to achieve the essential 'compaction to refusal'. Any backfilling should be with clean, crushed aggregate. It's doesn't have to be a Type 1 - a Type 2 or even a simple 50mm crusher run wil be fine, but "soil" should be a no-no.
As for the choice of flags, that depends on the size and shape of teh pool. It is unlikely an 'off-the-shelf' circle pack will work out with anything near a degree of accuracy. You would be better off buying large rectangloe of your preferred paving and then double-taper cutting them to shape as required.
https://www.pavingexpert.com/cut_in06#whats-a-fan-radius
Posted: Thu May 14, 2020 2:26 pm
by Ian-M
OK, thanks Tony - makes complete sense. I have some Type 2 on order so will use that as the base for compaction.
On the higher bits of the slope which I didn't have to build up, I'll just create a 100mm trench and use the 'regular' 100mm sub-base thickness. Where I built the ground level up by a few inches (per my original post), I'll dig out the few inches of freshly piled soil back down to the original dirt level - then dig a 100m trench - and fill the lot to the new level with Type 2. Once compacted, that will give me a sub-base loop round the entire pond - some 100mm thick and some maybe 150-200mm thick - but obviously level on the top surface.
I hope this makes sense, can take another pic if needed. Does that sound right?
Re: the fan shape, I'm now thinking to go back to a less elaborate shaped pond - not sure if I have the skill, equipment or confidence to do that. I'll see what the boss thinks.
Posted: Sat May 16, 2020 10:16 am
by Tony McC
As long as you have removed all topsoil and sub-soil ~ the stuff with organic content ~ you should be fine.
A heart is an ambitious shape but that doesn't mean it's beyond you. As long as you pre-plan, get everything worked out in advance, and try a 'dry run' of the cute pieces before committing them to concrete, you should be OK.
Posted: Thu May 28, 2020 3:31 pm
by Ian-M
Of course, sound advice - thanks again Tony. Its been a while since I asked for help from this forum - it was back in the day when the other Ian-M was a wee 41 1/2 year old shed builder Congratulations both on a great looking website.
Update
I have now dug down 12-18 inches into the organic stuff and filled with Type 2, prior to laying the concrete collar this coming weekend. Regarding the shape, I have decided to use landscaping rocks across the top of the heart, to largely remove the need of creating those curves with slabs. For the remaining curves I will use the suggestion you made about creating the radius curves.
Will post an image when done in case anyone is interested. Thanks again, Ian
Updated picture
Posted: Mon Jun 01, 2020 2:29 pm
by Tony McC
I'm always interested to see how projects progress.....
Posted: Tue Jun 23, 2020 5:51 pm
by Ian-M
Thanks again Tony - updated project pics on link below. Concreted collar ended up a bit rough but solid underneath and therefore fit for purpose - will post final pics with waterfall and edging once I've got my head around the design.
thanks Ian
My pond pics
Posted: Fri Jun 26, 2020 2:07 pm
by Tony McC
I hadn't really appreciated the scale of it all until I saw the people (you + 1?) stood in "The Hole" - that's really quite impressive!
Posted: Mon Jun 29, 2020 11:28 am
by Ian-M
Thanks Tony, I'm quite pleased because it was all hand dug with my granddads' old spade that I used to dig his plot with in Aintree back in the day. That's me and my son in the hole - he worked on on it during his furlough. The levels were done with string and spirit levels. We designed a small run-off section (25mm low point on the concrete collar) and it 'breached' exactly where we wanted it to.
Have added an updated pic and will continue to add pics as we build out the waterfall and filtration. The latest pic just shows the pond full with a temporary edging to stop the liner blowing in while I figure out next steps. I know I have been inspired and taken confidence off many other's updated pics down the years (and the supporting comments) so will keep sharing.
I'm conscious not to keep popping this thread back up to the top, as others need help/advice more than me. I'll just keep the pics updating for anyone who's interested rather than keep reposting.
Best wishes to you all. Work like this reminds me not only how hard it is, but how much of a skill it is too. Ours is a bit Heath Robinson but I have massive admiration for those who do this for a living.
Posted: Tue Jun 30, 2020 10:19 am
by Tony McC
Don't you worry about 'bumping' this thread to the top - it seems plenty of readers are quite keen on following your adventure! Post away whenever you have content to share, it's fine by me!