
Last year the team and I completed a challenging, award-winning water garden
& hard landscaping project in the grounds of a Grade II listed
property in North London. This photo diary of the garden design and build project is a continution and expansion of a previous post: Award-winning Garden Landscape Design for Koi Fish Pond Catches the Imagination. Jump to the first post or scroll
down to see, literally, how we transformed this neglected spot into a haven for our
client's collection of gloriously coloured Koi carp.
The area for the series of three-tier Koi Ponds had been overlooked for years and, due
to the grade II status of the house, we were prevented from using mechanical
diggers or transport. In total we dug and excavated over 150
tonnes of earth and rubble by hand hand – that's the equivalent to the
weight of a blue whale and young calf or 24 African elephants or the entire volume of a
pretty large living room! Planning every detail in advance was essential.
RESTRICTED ACCESS
Digging by hand wasn't the end of it, access to the street and skip was convoluted. Each, frequent, journey meant a trip walking (pushing a full wheel barrow) up two steps, along a path, up a series of metal steps, along a very narrow metal bridge, through French doors, across the expansive drawing room, down a hallway and out through the front door. And back again. The total distance from the work site to the skip outside was approximately 50 metres (the length of an Olypmic-sized swimming pool) and a further metre down steps to the lower levels. Forget the gym, we definitely had Olypmian-sized muscles at the end of it!
Nor were we permitted to use any other part of the garden for storage or as a works area either to fabricate the shutters or mix the concrete, which meant tricky working conditions and precision planning. Back-breaking work but character building. Each project generally has its own unique challenges – this one more than most – which in turn offers insight and experience which can be applied to the next one. We were very happy with the end result and if you have any questions not answered here please feel free to drop me or Mick a line: email Claudia (design & project management) or email Mick (build & landscaping).
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This design and build project began onsite with the team clearing a neglected and overgrown part of the large grounds of the house. This revealed a 5x3.5 metre paved area which was at the top of a series of steps almost two metres above the basement level and over five metres from the rear of the house.

The lower ponds were constructed first. The existing stone steps and brick walls were then broken out and removed to the skip, new wall to be built using reclaimed bricks.
The excavation of the main pond required the use of a conveyor system to
remove spoil from the excavation, discharging directly into
wheelbarrows for transport on the long journey through the house to the street and a skip.

Stone steps leading up from the basement provided access to the area.
Additional access at upper levels was via the drawing room, where
French windows opened onto an ornate metal bridge. Three steps then led
down to a short path and the overgrown paved area. Between the house,
paving and on each side of the stone steps were several small, planting
areas which had once been terraced to accommodate the difference in the
levels but was now seriously overgrown and thick with vegetation.
The existing terracing was provided by low-level, brick retaining
walls – these all had to be demolished, and their foundations broken
out, to create space for the lower ponds. These were eventually replaced
with 10 new, one-piece Yorkshire
(a hard-wearing and durable sandstone with a tight grain) steps which
were each over two metres wide, would eventually create an imposing
approach to the upper levels and a viewing point over the lower ponds.

INTRICATE INSTALLATION
The area for the two lower ponds had been dug out so they would be at a level 850mm lower than the main pond. The smaller ponds wer, internally, approximately 1.5 long by 1 metre wide and 750mm deep. The main pond above was more than twice as large, at 3.5 x 2.25 metres and over 1.5 metres deep.

All three ponds had to be constructed out of reinforced concrete, (the client feared the possibiity of ground settlement and using the reinforced concrete method copes better should this happen). So to accommodate the client’s preferred method of construction we made over 20 wooden shutters from plywood and many 100mm by 47mm timber pieces.
The difference in levels between the upper and lower ponds meant it was necessary to make wooden chutes (see above) to channel the concrete which was all mixed on site.

The method of construction was to cast the base slab of each pond, fix the reinforcing mesh and set the inner and outer shutters and cast the walls.


Pipe openings were formed through the 150mm thick concrete walls. Sufficient excavated material was kept to be used as backfill around the ponds.







Drainpipes were installed under the main steps to allow connections to the overflow pipe, and drain gully, to be set into the filter pit concrete slab. The brick walls and brick risers were then rebuilt.
The project was completed by the installation of a bespoke fish head fountain, commissioned by the owner.




Part of the filtration system and the pumps were placed beyond the rear wall of the main pond and below ground. This filtration pit needed to have a system of removable, hardwood decking panels to allow access for maintenance.
To accommodate the large vortex, the filter and the pumps, the internal dimensions resulted in a filter pit that was 3.25 metres long by 1.25 metres wide and over 1 metre deep. This space was constructed using dense concrete blocks that were built on a reinforced raft foundation. The edges were then thickened to 450mm around the edges.

The rear wall of the main pond (see above) became the
front wall of the filter chamber. Reinforcing mesh was placed behind
the concrete blocks and the void was then filled with concrete and
finally all the ponds were fibre glassed.





Lighting was to be installed in all the ponds, two waterspouts in the
smaller ponds and a large fish head water spout was installed in the
larger pond.










FACTS & FIGURES
- 55 cubic
metres / 120 tonnes hand dig excavation
- 18 cubic
metres / 40 tonnes broken brick and concrete foundations
- 12 cubic
metres / 26 tonnes concrete mixed on site with a 110 volt electric mixer
- 21 tonnes /
840 25 kgs. bags ballast
- 5 tonnes / 200
25 kgs. cement
- 4,500
reclaimed yellow stock bricks
- 500 Class B
engineering bricks
- 10 No.
bullnosed Yorkstone steps 2.2m x 50mm
- 15 square
metres Yorkstone paving
- 80 25kgs. bags building sand
- 100 25kgs.
Sharp sand
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PRESS COVERAGE
Download the ProLandscaper Article: 'Levels of Calm' or visit the magazine online at:
Pro Landscaper Magazine >
We are also in The Garden Network Blog >
The EFIG Interior Landscaping Industry >
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CONTACT DETAILS
Claudia de Yong Designs
London & Petworth
CALL US ON: 07881 622825 or 020 7938 2063
EMAIL: claudia@claudiadeyongdesigns.com
VISIT WEBSITE: www.claudiadeyongdesigns.com
Claudia is also on WhatsApp
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