How to design the terrace drain outlet
As a common leisure space in modern buildings, the drainage design of the terrace directly affects the user experience and building safety. Recently, the terrace drainage issues that have been hotly discussed on the Internet mainly focus on material selection, slope design, drainage outlet layout, etc. The following is a professional design plan compiled based on hot topics in the past 10 days.
1. Comparison of current mainstream drainage outlet design types
| Type | Advantages | Disadvantages | Applicable scenarios |
|---|---|---|---|
| linear drainage channel | High drainage efficiency (about 3L/s) | High installation accuracy requirements | large terrace |
| point floor drain | Low cost (50-200 yuan/piece) | Easy to clog | small balcony |
| Hidden drainage | Strong aesthetics | High maintenance costs | High-end residential |
| siphon drainage system | Fast drainage | Professional construction required | commercial complex |
2. Key design parameter standards
According to the requirements of the Ministry of Housing and Urban-Rural Development’s "Technical Specifications for Roofing Engineering" (GB50345-2012):
| Project | Standard value | Remarks |
|---|---|---|
| minimum slope | 2% | When draining in one direction |
| Drainage spacing | ≤6m | Epoxy floor needs to be encrypted |
| Drainage pipe diameter | ≥75mm | Recommend ≥110mm in northern areas |
| Drainage flow | ≥1.5L/(s·㎡) | Rainstorm intensity formula calculation |
3. Solutions to common problems in construction
1.Poor drainage problem: 37% of the complaints in the recent Douyin #patiodecoration topic involve this issue. It is recommended to adopt a double slope design (main slope 2% + local 3%) and set up a grit chamber.
2.Winter freeze problem: A hotly discussed case in the northern region of Zhihu shows that you can choose electric heat tracing drainage pipes (power 30-50W/m) or add an insulation layer to the drainage outlet.
3.Mosquito breeding problem: Xiaohongshu users recommend the combination solution of deodorant floor drain core (water seal depth ≥50mm) + stainless steel filter (pore diameter ≤5mm).
4. Application trends of new materials
| Material | Features | price range |
|---|---|---|
| Polymer drainage board | Compressive strength ≥300kPa | 80-150 yuan/㎡ |
| stainless steel grille | 304 material, load-bearing 1.5T | 200-400 yuan/meter |
| self cleaning coating | Contact angle＞120° | Increase cost by 30% |
5. Design process suggestions
1.hydrological calculations: Drainage capacity was reviewed based on the intensity of local heavy rains that occur once in 50 years. The recent #ExtremeWeather topic on Weibo showed that rainfall in many places exceeded the standard by 30%.
2.Structural calculation: It has been mentioned many times in popular Douyin videos that reinforced steel bars (diameter ≥8mm@150mm) are needed around the drainage outlet.
3.Dynamic testing: The acceptance method shared by Xiaohongshu Master: Continuously inject water at a flow rate of 5L/min, and check whether the depth of water accumulation is <3mm.
Through the above structured design plan, we can effectively solve the problems of water accumulation, leakage, and odor return on the terrace that netizens have recently been concerned about. It is recommended to use BIM software to conduct drainage simulation before construction to ensure the design effect.
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