Setting Method Of Drainage Slope During Installation By Terrazzo Manufacturers

During the installation process of terrazzo flooring, the setting of drainage slope is a critical step that directly affects the functionality of the floor (such as drainage efficiency, slip resistance) and durability. The following systematically analyzes the method of setting drainage slope from three aspects: design logic, construction steps, and quality control:

1, The core logic of drainage slope
The essence of drainage slope is to guide water flow quickly to the drainage outlet by tilting the ground, avoiding water accumulation and seepage. It is necessary to balance "drainage efficiency" and "walking comfort": a slope that is too small (<1%) is prone to water accumulation, while a slope that is too steep (>5%) affects aesthetics and is prone to slipping.

2, Construction steps for setting drainage slope
1. Design phase: Clarify the drainage direction and slope value
Drainage direction design:
According to the site functions (such as bathrooms, corridors, and factories), determine the location of drainage outlets and choose "single slope" (single directional drainage) or "double slope" (two-way drainage). For example:
Toilet/shower room: The drainage outlet is centered and designed with a "four-way slope" (with the drainage outlet as the lowest point and inclined towards the center from all sides);
Long corridor: make a "single slope" along the length direction, with drainage outlets located at the ends;
Industrial plant: Based on equipment layout, create a "local slope" (equipment area slope towards drainage ditch).
Slope value calculation:
Reference specifications and scenario requirements:
Recommended Slope Description for Scenarios
2% -3% shower area in civilian toilets can be increased to 3% -5%
1% -1.5% of public corridors balance drainage and walking comfort
Industrial plant/garage 3% -5% heavy-duty, high-frequency water usage scenario
Balcony/terrace 1% -2% to avoid rainwater backflow

2. Grassroots treatment: laying the foundation for slope gradient
The flatness and slope accuracy of the base layer (concrete cushion layer/leveling layer) directly determine the drainage effect of the terrazzo surface layer.

Grassroots leveling:
Level with cement mortar (1:3) and adjust the thickness according to the slope (e.g. 1% slope requires lifting 1cm per meter). During construction:
Use a laser level to calibrate the lowest point of the drainage outlet, and draw a "cross control line" to determine the slope direction;
Check the flatness with a 2m ruler, with an error of ≤ 3mm;
The base strength should be ≥ C20, without hollowing or cracks (to avoid cracking of the surface layer in the later stage).
3. Grid layout: comply with drainage logic
Terrazzo floors are usually equipped with dividing bars (copper/glass bars), and the direction of the dividing bars should be consistent with the drainage direction to avoid "water accumulation inside the bars".

Grid positioning:
The spacing between grid bars should be based on the design (usually 1-2m), but the area around the drainage outlet should be densified (spacing ≤ 0.5m) to guide the water flow;
The height of the dividing strip should be consistent (3-5mm exposed to the surface layer) to avoid local height differences damaging the slope;
At the junction of the dividing strip and the drainage outlet, a "horn mouth" transition is made to ensure smooth water flow.
4. Surface construction: precise control of slope
When constructing the terrazzo surface layer (prefabricated board/cast-in-place), the slope needs to be controlled through three steps: "paving, leveling, and testing".

Ready made terrazzo (on-site pouring):
Mixing slurry: The water cement ratio should be controlled at 0.4-0.5 to avoid being too thin (low strength) or too thick (difficult to scrape flat);
Laying sequence: Spread from the lower part (drainage outlet) to the higher part in a reverse slope, using the self flowing property of the slurry to assist in forming the slope;
Scraping control: Use an aluminum alloy scraper to level along the drainage direction, and use a laser level to detect the slope while scraping, with an error of ≤ 2mm;
Compaction and finishing: Use an iron trowel to press and finish, avoiding local depressions (prone to water accumulation).
Prefabricated water milled stone slabs:
Cushion adjustment: Use dry and hard cement mortar (1:3) to create a slope on the base layer, with the thickness calculated based on the slope (e.g. 1% slope, with a cushion layer thickness of 1cm per meter);
Plate laying: Lay from the drainage outlet outward, lightly tap the plate with a rubber hammer, adjust the height difference, and ensure that the joints are straight and the slope is consistent;
Jointing treatment: The jointing material should be 2-3mm below the surface of the board to avoid water accumulation.

5. Special treatment of drainage outlet
The drainage outlet is the "endpoint" of the drainage system and requires special attention to:

Location: Located at the lowest point of the site (such as the center of the bathroom floor drain), with a slope increase of 3% -5% within a 50cm radius;
Connection: The connection between the terrazzo surface layer and the drainage outlet (floor drain/drainage ditch) should be sealed with elastic sealant to prevent water seepage;
Test: After construction, conduct a water splashing test to observe whether the water flow quickly gathers at the drainage outlet. If there is no accumulated water, it is considered qualified.
3, Key points of quality control
Tool calibration: Laser level, ruler, and slope ruler need to be calibrated to ensure measurement accuracy;
Process inspection: After each process (base leveling, surface scraping) is completed, the drainage effect is preliminarily verified using the "water splashing method";
Finished product protection: During the surface maintenance period (7-14 days), avoid trampling, water accumulation, and prevent slope deformation;
Special scenario adjustment:
Low temperature environment (<5 ℃): The slurry solidifies slowly, and the scraping time needs to be extended to avoid slope loss;
Heavy load scenario (factory building): The slope can be increased to 5% -8%, but structural calculations are required to avoid deformation of the base layer.
summarize
The drainage slope setting for terrazzo installation requires "design first, precise base layer, and strict control of surface layer", combined with site functions and material characteristics (prefabricated/freshly made), to achieve a balance of "efficient drainage and comfortable walking" through tools (laser level, scraper) and processes (paving, scraping). After construction, it must be verified through a "water splashing test" to ensure that there is no accumulated water before delivery.