Clipstone Retaining
Wall Block
Clipstones are an interlocking retaining wall system for applications up to 960mm in height.
No mortar or expensive footings are required, they simply stack together.
There are 16 Clipstones per square metre of wall area.
The dimensions of the block are 390mm in length 160mm in height and 190mm in width.
The Bull Nose Cap is 390mm in length 65mm in height and 230mm in width.
· Shovel and wheelbarrow
· A level.
· Drainage material such as free draining sand or gravel.
· Agricultural drain.
· 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.
· Lump hammer and rubber mallet.
· 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.
The are five colours to choose from
Step 1.
Choose the construction method. There are two ways in which these blocks can be constructed, depending on what type of footing is used and how high the wall is.
Method 1 - Concrete footing or Method 2 - Sand footing (Clean screened river sand or blue metal dust) may be used for walls up to 800mm in height (5 courses). The cores of the block may be required to be filled with sand please see engineering details.
Remember the first course is partly buried (65mm) in the ground.
E.g. – A wall 19.5 metres in length & 640mm high.
19.5 divide by 0.39 = 50. 640mm divide by 0.16 = 4 courses plus a cap. Number of blocks required is 200 blocks and 50 caps.
Step 2.
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 160 mm increments. If steps are required in the footing, space them out in 390mm increments, to avoid cutting blocks. Use a piece of 160 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.
Step 3.
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.
Step 4.
While the concrete is still wet lay the first course of blocks with the retaining lug 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 course 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 footing (Clean screened river sand or blue metal dust) 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 has unstable soil, you may have to dig down deeper and replace the soil with road base or granite type material and compact, to give you a firm, level base to place your bedding sand. Then fill the trench with 80 to 90mm of coarse sand and screed sand evenly in the trench. Do not compact the bedding sand. Lay the first course of blocks with the retaining lug down into the sand and bed the blocks using a rubber mallet, care should be taken to make sure this course is level.
Step 5.
Place the locking lug of the second course behind the first course and using a running bond pattern {that is the vertical joint of the bottom course, should be in the middle of the top block}. If the wall needs to be straight at the ends, instead of tapering, then a block will need to be cut in half and used every second course. For external corners a split face corner block will need to be used. (There are left and right hand blocks.)
When building an external or internal corner some blocks will have to be cut to keep the running bond pattern throughout the rest of the wall. If a curved wall is required single core blocks will have to be used and cut on an angle.
Step 6.
Place the agricultural drain behind the first course, making sure that sufficient fall is obtained to allow water to drain away. Cover drain with free draining gravel or coarse sand to just below the top of the second course, to a width of 200mm to 300mm (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 course. Repeat these steps until you are ready to lay the capping course.
Step 7.
First make sure the surface of the top course is clean and dry. Lay four to five caps on top of the wall to see how much overhang you would like, then using a string line to ensure the caps are straight, glue them down one by one with construction adhesive. If there are corners or curves in the wall, caps will have to be cut to suit.
