Short answer: A paving surface that stays level and does not sink depends on three things: a well-compacted subgrade and sub-base, curb stones that stop the blocks moving sideways, and a block thickness that suits the traffic load. The correct order is to set the curb stones to line and level first, then lay the blocks inside the edge.
What curb stones do
- Hold the blocks tightly together so they do not shift sideways
- Stop the bedding sand from washing out, keeping the surface level throughout its life
- Set the line and level of the whole paved area
Steps for laying paving blocks and curb stones
- Set out line and level — mark the edges, the finished level and a fall so water can drain away
- Excavate and compact the subgrade — remove soft topsoil, then compact firmly
- Build the sub-base — place a sub-base material such as crushed rock and compact in layers; the designer should set the thickness based on the expected load
- Set the curb stones — place them to line and level and fix the base firmly before laying blocks (fixing method as specified by the designer)
- Spread the bedding sand — spread sand to an even thickness across the area and screed it level; do not walk on the screeded sand
- Lay the blocks in pattern — work from the edge inwards with even joints, and cut pieces to fill along the edges
- Compact and sweep sand into the joints — compact the surface with a plate compactor, then sweep fine sand into the joints until full; joint sand locks the blocks together
Choosing block thickness for the traffic load
For example, CPS interlocking (zigzag) paving blocks come in 4 thicknesses
| Size (cm) | Weight/piece (kg) | Pieces/pallet |
|---|
| 22.5 × 11.5 × 6 | 3.20 | 700 |
| 22.5 × 11.5 × 8 | 4.00 | 500 |
| 22.5 × 11.5 × 10 | 5.50 | 400 |
| 22.5 × 11.5 × 12 | 6.40 | 320 |
- Meets TIS 827 and TIS 2035 and certified Made in Thailand (MiT)
- Standard colours: grey, brown, black, red, orange, yellow · special colours (made to order): light blue, green, rose pink, coral pink
- The thickness actually used should be specified by the designer based on vehicle loads in the area
Choosing curb stone size
| Size (cm) | Weight/piece (kg) | Pieces/pallet |
|---|
| 10 × 20 × 50 | 23 | 80 |
| 15 × 30 × 100 | 109 | 18 |
| 17.5 × 28.5 × 100 | 132 | 18 |
| 20 × 35 × 100 | 168 | 12 |
| 35 × 35 × 100 | 265 | 5 |
- 30 × 40 × 100 and 20 × 45 × 100 cm are Department of Highways standard products
- Also available: wet-cast curbs 15/20 × 45 × 100 cm and grated curbs 35 × 35 × 120 cm for roadside water inlets
- Curb stones are certified Made in Thailand (MiT)
- Use the weight per piece to plan labour and lifting: small sizes can be lifted by hand; 1 m long units need lifting equipment
Common problems and causes
| Problem | Common cause |
|---|
| Surface sinks into dips | Subgrade or sub-base not compacted enough |
| Blocks spread apart | No curb stones, or unstable edges |
| Blocks rock | Joints not fully filled with sand, or uneven bedding sand |
| Standing water | No fall set at the levelling stage |
Frequently asked questions
Should curb stones go in before or after the blocks?
Set the curb stones to line and level first, then lay the blocks inside the edge.
How thick should driveway blocks be?
CPS interlocking paving blocks come in 6, 8, 10 and 12 cm. The thickness actually used should be specified by the designer based on vehicle loads in the area.
Can I buy paving blocks and curb stones in one place?
Yes. CPS supplies paving blocks, paving slabs and curb stones in one place.
Enquiries and quotations: CPS, tel. +66 61 403 4448 · LINE @ccp-pavingstone
Products: Interlocking paving block · Curb Stone · Concrete paving slab · Crushed rock
