Garden Lockstone
Garden Lockstones are an interlocking retaining wall system that requires no
mortar or expensive footings, they simply stack together to transform any area
into a landscaped paradise.
Garden Lockstones
are flexible enough to build walls from a simple garden bed to a terraced
masterpiece and can be built up to 1.5 metres in height.
There are five colours to choose from
You will need:
- Shovel and wheelbarrow
- A spirit level or water level.
- Drainage material such as coarse river gravel or 20 mm blue metal.
- String line and pegs to set out the wall.
- Garden hose to mark out curves in wall
- Can of spray paint to mark out footing.
- Agricultural drain.
- Motorised plate compactor.
- Lump hammer
- Straw broom.
- Gloves & Eye protection.
Check with your local Council, as to their requirements for construction of retaining walls. They may require the wall to be designed by an engineer.
Calculating amount needed
- The dimensions of the block are 390mm in length 130mm in height and 230mm in width. The Bull Nose Cap is 390mm in length 65mm in
height and 230mm in width.
- Alternately, there are 19.72 lockstones per square metre of wall area.
- Measure the length and height of the wall
-
There are a number of ways in which these blocks can be constructed, depending on what type of footing is used and how high the wall is.
Hollow blocks can be used up to one metre in height; walls above one metre require solids from top to bottom with a concrete footing. (see engineering details).
Method 1
- Sand footing – Use a solid block on the first coarse, hollows for the rest and a capping coarse on the top. (Solids can be used all the way if you wish).
Method 2
- Concrete footing – Use hollow blocks all the way and a capping coarse on the top. (Solids can be used all the way if you wish).
- Choose one of the methods and calculate the number of hollows, solids and caps required. Remember the first coarse is half buried in the ground.
For example – A wall 15.6 metres in length and 910mm high. So 15.6 divide by 0.39 = 40. 910mm divide by 0.13 = 7 coarses plus cap.
Method 1 |
Method 2 |
Hollow |
240 |
Hollow |
280 |
Solid |
40 |
Solid |
N/A |
Capping |
40 |
Capping |
40 |
Walls up to 1 metre in height
- After setting out and marking the position of the wall with the spray paint, dig the foundation trench about 140mm to 160mm deep and approximately 350 to 400 mm wide. Make sure the trench is level. For steep sites, the trench may have to be stepped up or down in 130 mm increments.
- If steps in the footing are required, space them out in 390mm increments, to avoid cutting blocks. Use a piece of 130 mm wide timber to form up the steps and peg them securely with timber or steel pegs which can later be removed after the first coarse has been laid.
- If you use a concrete footing clean out all loose dirt and make sure the bottom of the trench is level and firmly compact. Then pour approximately 75mm of concrete into the trench and level off. This acts as firm base for the first course to bed into and prevents the bottom course from moving out under pressure. Reinforcement in the concrete is not necessary.
- While the concrete is still wet lay the first course of blocks with the retaining lip down into the concrete. Level each unit side-to-side and back to front. Use a string line along the back of the blocks for alignment. Care should be taken to make sure this coarse is level. If it is not exactly level then all ensuing courses will not go together properly and the wall may ultimately, need to be rebuilt.
- If you are using a sand base first clean out any loose dirt from the trench and make sure the bottom of the trench is level and firmly compact. If the bottom of the trench is soft or unstable soil, you may have to dig down deeper and replace the soil with road base or granite type material and compact that to give you a firm, level base to place your bedding sand. Then fill the trench with 80 to 100mm of coarse sand and screed sand evenly in the trench. Do not compact the bedding sand directly, it compacts under the blocks.
- Place the block into the sand with the locking lug down and bed the block by using a rubber mallet. Level each unit side-to-side and back to front. Use a string line along the back of the blocks for alignment. Care should be taken to make sure this coarse is level.
- Place the agricultural drain behind the first coarse, making sure that sufficient fall is obtained to allow water to drain away. Cover drain with river gravel, or blue metal, to just below the top of the first coarse, to a width of approximately 200mm (see engineering details). Now shovel and compact the backfill, which is your existing site soil.
- Sweep off any loose dirt from the top of the blocks and you are now ready to lay the next coarse.
- Place the locking lip of the second coarse behind the first coarse and using a running bond pattern {that is the vertical joint of the bottom coarse, should be in the middle of the top block}. If the wall needs to be straight at the ends, instead of tapering, then a solid block will need to be cut in half and used every second coarse.
- After the second coarse has been laid place the river gravel, or blue metal behind the wall, as before and shovel in the backfill and compact. Repeat these steps until you are ready to lay the final coarse. This coarse is a solid capping block, which can be glued down with construction adhesive.
- When building curves it may be necessary to remove the outsides of the locking lip and wings to maintain even spacing between blocks. This can be done, by chipping off with hammer, a bolster or cold chisel. Care should be taken not to remove too much of the locking lip, only what is necessary. You must use eye protection when doing this. For tight curves you may have to cut the length of a block to keep a consistent running bond pattern.
