In short: A precast drainage channel lasts when it has a firm bed, the correct fall and tight joints. The main steps are: excavate along the line → compact and prepare the bedding → lay the channel starting from the downstream end → seal the joints → backfill and compact both sides → fit covers rated for the load in use. The fall and channel size should follow the designer's drawings.
Before you start: choose the right channel
- U-Ditch: open channel that takes covers; suits roadsides, car parks and around buildings
- V-channel (shallow V drain): shallow drain that vehicles can drive over, no cover needed; suits concrete yards and entrances
- See the differences between channel types in detail in How many types of precast drainage channel are there?
Installation in 6 steps
- Set out line and levels — drive pegs, stretch a string line and set the channel invert levels at the start and end according to the drawings
- Excavate — wider than the channel so the sides can be backfilled and compacted, and deep enough to allow for the bedding layer
- Prepare the bedding — compact the existing soil firmly, lay bedding material (such as sand, crushed rock or lean concrete as specified), then screed it to the required fall
- Lay the channel — start at the downstream end and work upstream, butt units tightly together and check the level of every unit
- Seal the joints — grout the joints with sand-cement mortar to stop water seeping out and soil washing into the channel
- Backfill and compact both sides — backfill in layers, compacting both sides evenly so the channel does not tilt or crack, then fit the covers
How to choose a channel cover
| Use above | Recommended cover |
|---|
| Footpaths, pedestrians | Concrete cover for footpaths |
| Small vehicles, cars | Channel set with concrete cover for small vehicles, or steel cover |
| Trucks / factory yards | Heavy-duty steel cover (ask our sales team for the model) |
| No cover wanted, vehicles cross | V-channel |
Common problems and how to prevent them
- Channel settles or cracks: bed not firm, or backfilled on one side only → compact the bed and backfill both sides at the same time
- Water ponds in the channel: fall is not continuous → check the level of every unit before sealing the joints
- Covers rock or break: cover not rated for the load in use → choose covers from the table above
- Soil washes into the channel: joints not sealed → grout every joint
FAQ
Can I install the channel myself?
Small channels and V-channels can be lifted by hand; large channels should be placed with a forklift or crane.
How do I connect channels in several directions?
Use a channel catch pit designed to connect channels from several directions.
Can I get drawings?
Download them from the product page, or ask our sales team.
Enquiries and quotations: tel. +66 61 403 4448 · LINE @ccp-pavingstone
Products: U-Ditch · V-channel · Footpath channel cover · Channel set with cover for small vehicles · Steel drainage channel cover · Channel catch pit
