Prefabricated House Roof Waterproofing Requirements
The waterproofing requirements for the roof of a prefabricated house are as follows:
Material Selection: Reliable materials should be selected, such as SBS (polymer-modified bitumen waterproofing membrane). From the perspectives of safety and durability, two layers of waterproofing treatment are usually adopted to enhance the waterproofing effect and reduce the risk of leakage.
Base Layer Preparation: The flatness and dryness of the base layer are crucial. Ensure that the base layer is flat and dry. For the roots of parts protruding from the roof, use mortar to create rounded corners. Pay special attention to the treatment of details such as parapet walls and exhaust vents, as these areas are often prone to leakage. Proper detail treatment can effectively prevent leakage.
Pre-construction Preparation: Before construction, apply cold primer oil, which helps enhance the adhesion between the membrane and the base layer. At the same time, perform additional layer waterproofing treatment on parts protruding from the roof. The additional layer has a width of 50 cm, with the upper part being 30 cm and the lower part being 20 cm, further strengthening the waterproofing performance of these key areas.
Membrane Laying: The overlap width of the two layers of membranes should be 10 cm, and the membrane laying should be dense without any hollow areas, as this would affect the waterproofing effect. The membrane laying direction should follow the drainage direction. The membrane at the rainwater outlet should be rolled in by 10 cm, and the membrane on parts protruding from the roof should be rolled up by 30 cm to ensure that rainwater can drain smoothly and avoid water accumulation leading to leakage.
Water Closure Test: After completing the waterproofing construction, a water closure test must be carried out. Block the rainwater outlet, fill with water to a level 3 cm higher than the highest point, and maintain it for 24 hours. Then carefully check for any water leakage points downstairs to verify the quality of the waterproofing construction.
Protective Layer: Create a mortar protective layer. The protective layer can prevent the waterproofing layer from being damaged by subsequent construction or external factors, extending the service life of the waterproofing layer.
Other Recommendations: Before waterproofing, a layer of 9 cm thick polystyrene board insulation material can be laid on the roof for energy-saving and insulation purposes. Before construction, create a slope-finding layer, usually using perlite material, to ensure that rainwater flows smoothly to the rainwater outlet and that there is no water accumulation on the roof. The slope is generally 1% or 2%.
