Building Walls, Retaining Walls, Stairs and Fences

In the mean time that the paving work was done we started building garden walls and water-side stairs. Like the paving the walls are an other serious compromise to Japanese garden principles that we had to solve. Here we not only wanted the walls to look more or less natural, the construction had to be simple without a requirement to use machines of any type. As this is all Do It Yourself work we took this into account during the material selection.

Fences can be valuable visible elements in a Japanese garden. In Tsubo-en we did not have fences, only two hedgerows. In March 2009 we created a small bamboo fence to replace the temporary (!) construct that closes off the main entrance path in the front garden compartment). In Construction of a bamboo fence (take gaki) you find all details of this little venture.

Located in the water front compartment we have the two stairs that lead down to the "water-frond terrace". Also in the water-side compartment we build two narrow utilitarian stairs at both far ends of the water side, that make the water bank better accessible.

After the built of the drive we have started building the walls. Between the front garden and the street we have a 3 meter (10 feet) greenbelt. The wall at the front adjoins that greenbelt.

Please see the groundplan in Design the architecture or in the Table of Contents to understand the exact locations.

The walls in Tsubo-en have two purposes that is both functional and decorative. The walls in the front garden compartment are used to mark the boundaries of the garden. These have purposely been kept low so as to allow people passing by to see the garden. The walls in the back, although an attractive ornamental feature in itself, are meant to hold together our steep bank, hence it is a so called "retaining wall". Behind the house it is also meant to carry the duckboards that connect the main garden with the left garden.

The most difficult part of building a brick garden wall is working with the mortar, so we tried to avoid that.
For the walls we used a brick named "Garden wall" (what's in a name) that does not need any mortar. The front edge of the stone is broken which gives it a natural look. The color we took is a mix of dark-brown and dark-gray.

It is very simple to stack these stones, one on top of the other. On the back of the stone is a center mark that can be used to stack them in a staggered fashion. They do not require any mortar, but instead rely on small lips on the rear edge. These lips hook over the rear edge of the row below. This results in a stepped back effect that effectively results in a sloping wall. This construction can resist a lot of pressure from the rear side without toppling over. Although not required in the front garden this is an absolute must in the water front compartment.
Lay bricks in a staggered fashion so that joints occur over the middle of the underlying brick. Periodically check that your wall is straight and level. Use string guidelines and a carpenter's level to keep things lined up. Because brick garden walls like the ones we built, are only one brick thick, if you build a free-standing wall higher than 36 cm (15 inch, here three stone), you'll need to reinforce your wall with pillars.

The so called "Garden wall" bricks that we used measure 30 x 23 cm, 12 cm high (12 x 9 x 4.7 inch) and weighs 14 kg (28 lb) each. In the whole garden we initially used 900 of these. This did not include the low water front garden at the right side which was added later. The "Garden wall" solution is a so called dry stone wall and can be used as a low retaining wall.

First we made a foundation of these big 60 x 40 cm (1.3 by two foot) concrete tiles. These are pretty heavy. These where laid, over the full length, in a bed of some 20 cm (8 inch) sand.
The sand needs a good tamping down, to make it firm and flat. Without the use of machines this is a cumbersome manual task. I found some concrete poles or actually cylinders that I could use to that purpose, by rolling them over the foundation layer of sand.

The concrete-tile path came standard (photo: 1999). We have removed it to make place for a real Roji and used these stone (and the pile in the center) for the foundations of our walls.

Gardenwall
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In the front garden we did this job during the winter, meaning that the ground and the sand where very wet and the area was like a swamp. We had to dig extra trenches to get rid of the excess water. This was an extra hurtle to take while laying the concrete foundation tiles. As there is now way to make any level correction further down the road, it is very important to ensure that the foundation is perfect into all directions. Once that was done, we could begin laying and stacking the bricks.

Something to be aware of is the level of the street. On this photo our wall-foundation seams to be far too high. However what is the case is the fact that this was not the final street level. Later the street was replaced and raised to only some 10 cm (4 inches) under our foundation level. 99apr28
For practical reasons the "standard" path to the front-door was only removed after the alternatives had been completed. 99apr30
In the bottom-right you can just see the foundation. Later this has been coverer with only a centimeter (0.5 inch) of soil just to offer the grass that grows in the front to cover it. 990103




All the water front walls are actually "retaining walls".
A retaining wall with an earthen bank behind has to carry a very heavy loading. Simple walls of blocks are not able to withstand the pressure and may collapse, or be overturned. The design of these walls involves careful consideration and may in some cases involve calculations of the amount and type of reinforcements that can be required. Here our special purpose "Garden wall" offers great opportunity with the small lips on the rear edge now becoming indispensable.

The wall behind the house is 1 meter 45 cm high, the base at about 50 cm above water level. We did not use pillars because it is not freestanding.
Actually the walls at the back are meant to hold together our steep bank, hence it is a so called "retaining wall". Behind the house it is also meant to carry the duckboards that connect the main garden with the left garden.

The "Garden wall" is a so called dry stone wall and can be used as a low retaining wall.

As you see the wall is an attractive ornamental feature in itself.
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These stairs are built with L-shape concrete stone in the by now well know gray-tones.












The photo right-under shows the lips and notches in the back of the "Garden wall" brick.
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Here a sloping piece of ground behind the O-karikomi is terraced into two pieces of level ground and the wall is used as a free-standing wall.

A small strip of the foundation stones is left, just wide enough to be walked upon for maintenance purposes.
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The retaining wall at the right water front is used to divide the bank in two parts and make it easier maintainable. Mind you, easier, not at all easy.

This wall is constructed in the same way as the low wall in the front garden.
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This narrow utilitarian stairs is built using the same L-shape concrete stone as those used for the "water side terrace" stairways.
Here you see how it is situated next to the "herb garden terrace", here overseeing the whole left side garden in 1999.
Note the planting.
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Here we have the small stairway that connects to the left side of the waterside bank now 10 years later in 2008.

This is one of two utilitarian narrow stairways located on each far end, left and right, of the water front.
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This is the other utilitarian narrow stairways located on the far right of the water front. This is even less of a stair. It is merely just a few descending steps with planting in between. Nonetheless it serves its purpose well and actually is indispensable. 2456

What did not work well

Here we document what went wrong with regard to the walls and stairs.

  1. Only one thing went dramatically wrong here and that is the high brick water front wall behind the house.

    Building walls is a profession, so we learned.
    Below we will comment on what we think went wrong. Prove that we have learned is given as the result of the retry still stands proudly after ten years.


    Two reasons for the wall to collapse. The incline is very (too) high that in combination with the (too) soft base....!!!!!!!!!!

    Building walls is a profession, so we learned. Below we will comment on what we think went wrong. Prove that we have learned is given as the result of the retry still stands proudly after ten years. 99apr32

  2. Building a wooden platform, or deck, on a slope like the one behind the house, might be easier than building a retaining wall with a terrace. like we did. Nonetheless it is a beautiful wall, ornamental in its own right.
    A wooden deck can be very effective built onto very steeply sloped ground, or where there is not enough room to excavate a terrace. If we could start from scratch we are still not sure what we would have built.
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