Monday, 5 March 2012

Mark and Gaz Pond Build - Part One

The following article was originally published on Gaz and Marks Garden Blog - Alternative Eden as The Big Pond Build so far.

As regular followers of our blog will know we have been building a koi pond over the last 18 months. We have posted a selection of photos as work has progressed, but with the start of a new year we thought it would be a good time to explain the project so far.

We had previously built a small pond, that had originally been envisaged as a goldfish pond, however it was large enough for a few Koi and that sparked a keen interest in these elegant and beautiful fish. That original pond had various filter upgrades applied to ensure we could provide a good standard of water, but we knew that at some point we would want to build a larger pond.

Spending quite a lot of time debating the style and layout for the new pond, the design was sketched, tweaked and refined several times over the winter of 2009-10. I still have some of those sketches, made on the hotel note paper from a trip to Madeira late 2009.

As winter is not the best time to start digging out a pond we waited for the following spring. When the usual spring tidy up and planting had been completed we turned our attention to the new project. By which time we had the layout worked out in quite a lot of detail, aproximately a 20x10x6foot rectangular formal pond, with a curved path and raised beds leading to a seating area.
At the far end of the pond we planned to build a filtration house which would also screen off a garden utility area with 2 greenhouses and coldframes.

Burning garden waste at the start of the project.

Getting started with the first raised bed.
Getting there!
View across what will one day be the pond.
This was taken on Mark's birthday, there's dedication to the cause!
So with all this in mind we started work in May 2010. The first job was to build initial retaining walls for the first raised bed. We wanted to integrate a raised pond with raised beds to ensure the whole section of the garden was of a coherent design. Once these walls were built we could start the dig.
I calculated that we would be digging out something in the region of 35 tonnes of clay and chalk, and this all had to be dug by hand as we only have a very narrow and awkward access to the back of the garden. We knew that this task would be the biggest single job in the whole project, so much so that we knew it would not be completed before the autumn and wet weather weather arrived.
However that first summer we dug out most of the planned hole and had started the second raised bed. After about a foot of top soil we hit solid chalk, something we knew we would have to face, but had hoped it would be much deeper down than just a foot.

A well deserved rest.
Mark doing all the hard work again!
We developed individual tasks and skills for this (and not to mention developed muscles we had not used so much before). I would use the pick axe and fork to break the chalk, and Mark would shovel out the chalk into a barrow to be wheeled away.
During the winter we spent a lot of time scouring the net for some of the materials we wanted, including reclaimed roof tiles and windows for the filter house. We had numerous trips to local towns to pick up our bounty, ready to be stored and used once we got to the relevant stage.
Once spring 2011 arrived we were ready for the next push and completed the digging. We had deliberately not dug close to our neighbours fences incase the winter weather had caused the clay pond walls to collapse. There was not really any need to worry as there were very little in the way of cave ins, however we had to get this part finished off. The schedule we had set ourselves was quite punishing and the remaining spoil was removed over the course of a single weekend. If anything we probably pushed outselves too hard that weekend and it took a while to get over our strenuous efforts.
New fences up on the Left hand side, and back to the pond again!
Some initial planting in the first raised bed.
Rendering the walls.
Fences painted and the first raised bed is taking shape.

In the run up to the Easter Weekend we had our largest delivery of materials to date, and our small front garden was piled high with over 400 high density concrete blocks and several tonnes of sand, gravel and cement. We are lucky that our local builders merchants are happy to deliver when we are out at work, but the first driver got his left and right mixed up and placed everything where I needed to park the car!
We decided to build each wall on seperate footings, which made the overall job easier. It is traditional to pour a large solid concrete slab for the base with the walls built from the slab. However with the solid chalk (and checking with a local members of Kangei Koi Club) we knew that we were able to make our life easier without any risk to the structure.
The first walls were going up in early July, which at last meant that the risk of the clay caving in was greatly reduced. Once the first three walls were built we had to put in the bottom drains. This was another new skill we had to learn, setting the pipes at the correct angle and the two bottom drains level. The final wall could then be built and the pond had all 4 sides!

Pond showing the position of the filter pipework from the pond.
The following weekend we planned to start laying the base. We looked into having a ready mix concrete delivery, however realised that with the time allowed to barrow it round to the back (and the awkward access) we would rather not have the pressure and allow us to work to our own pace. It was this weekend that Mark blogged about, unfortunately I was ill and was unable to be very much help. Mark loaded up the barrow at the front, brought round the mixed sand and gravel, added cement, water and hand mixed several tonnes of concrete. I was at least able to get each barrow load leveled. This was a major landmark in the project, all the walls were in and the base laid. If we had stopped at this point the pond would hold about 3,000 gallons.

The first two raised beds were now complete, with coping stones and rendered walls, and the first raised bed was partly planted. We could have left the planting until after the pond was finished but were keen to get plants established, so several previously pot grown plants were planted out, along with a few new additions.

By early September I was worrying that the weather may turn and we laid the base for the filter house. As it turned out we have had a very mild and dry autumn which has allowed work to continue at quite a pace.

So with attention turned towards the filter house we laid the base and built the dwarf walls in October. The filter house is a wooden framed building supported on a concrete foundation and concrete block walls. As featured on this blog my dad was able to help us get the frame built quite quickly.
With the frame up we were able to get stuck into the tiling, (using the reclaimed tiles mentioned earlier), and by Christmas the roof was on and the walls clad in timber. The filter house is pretty much watertight going into the new year.

The mild weather continued into the Christmas period and we were able to build the final raised bed and the associated small water feature.
So with the start of a new year, thanks to the mild weather, we are ahead of schedule, with any luck we shall be finished before the summer starts!
Mark is planning to follow up this recap with a look into the design and research that has gone into this project, so stay tuned!

To see a selection of photos 'as it happened' please see here.


Part II will follow in due course!


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