Ⅰ.What is "TPO waterproof membrane"?
TPO waterproof membrane,or thermoplastic polyolefin waterproof membrane, is a new type of waterproof membrane made from thermoplastic polyolefin (TPO) synthetic resin,which combines ethylene propylene rubber and polypropylene using polymerization technology.Antioxidants,anti-aging agents,and softeners are added.It can be reinforced with polyester fiber mesh as an internal reinforcing material to create a reinforced waterproof membrane.It belongs to the category of synthetic polymer waterproof membrane products.
II. What are its performance characteristics?
TPO waterproof membrane combines the advantages of EPDM and PVC, possessing the former's weather resistance and low-temperature flexibility, and the latter's weldability. Unlike traditional plastics, this material exhibits high elasticity like rubber at room temperature, while being moldable like plastic at high temperatures. Therefore, this material has excellent processing and mechanical properties, as well as high-strength weldability. Adding a layer of polyester fiber fabric between two layers of TPO material enhances its physical properties, improves its tensile strength, fatigue resistance, and puncture resistance.
III. Construction Process of TPO Waterproof Membrane
1. Mechanical Fixing Method
Construction Process of TPO Waterproof Membrane Mechanical Fixing Method:
Clean the substrate → Lay the TPO membrane → Mechanically fix the TPO membrane → Hot air welding of the overlap edges → Construction of additional detail layers → Sealing of membrane ends → Weld inspection → Acceptance
(1) Construction can only proceed after the base layer meets the requirements.
(2) Insulation layer: The compressive strength, compression ratio, and deformation of the insulation layer should meet the requirements for roof construction.
Operational points
(1) Base surface treatment: The base layer should be clean, dry, and free of debris and sharp objects.
(2) Waterproofing layer laying: Before construction, accurate layout should be carried out to minimize joints; where there are joints, they should be staggered by at least 300mm, otherwise appropriate cutting is required; when the structural layer is a steel structure, the entire roll material should be laid perpendicular to the crest direction of the roof profiled steel sheet.
Laying in the surrounding area of the roof: The roll material can be laid in a direction parallel or perpendicular to the surrounding area.
(3) Waterproofing layer fixing: Mechanical fixing methods are divided into point fixing and linear fixing. Waterproofing roll material is fixed and installed using special fasteners. Spot welding is not allowed to temporarily fix the waterproofing layer during construction.
(4) Hot air welding of overlapping edges: All overlaps of the roll material are welded by hot air. At least two welding tests must be conducted before formal construction to ensure welding quality. The results of the welding tests will serve as the basis for welding adjustments.
(5) Detail Treatment
Detailed joints should be welded manually. The effective welding width for detailed treatment is smaller than that for surface treatment.
For internal corner flashing, install fasteners 150mm-230mm from the internal corner. Determine the position of the fasteners 13mm-25mm from the edge of the roll material. Apply approximately 3mm diameter edge sealant to the cut edges of the reinforced TPO roll material.
For external corner flashing, install fasteners approximately 150mm from the external corner. Determine the fastener position 13mm-25mm from the edge of the roll material. Apply approximately 3mm diameter edge sealant to the cut edges of the reinforced TPO roll material.
6) Membrane Termination Treatment
The membrane termination is sealed using a special termination strip and sealant.
(7) Weld Inspection
Each weld must be inspected visually and manually. Visually, molten slurry should be extruded from the weld edge. Manually, a special pointed tool is used; with slight force, it is moved along the weld. No missed welds or skipped welds indicate acceptance. If necessary, a peel test can be performed: when inspecting weld quality, a 2-3cm wide cut is made perpendicular to the weld using a hook knife or utility knife, and the cut strip is forcefully torn to check the welding quality.
2. Full Adhesion Method
The full adhesion method for TPO waterproof membrane is as follows:
Base surface cleaning → Positioning and marking → Node reinforcement → Large-area adhesive application → Membrane laying → Membrane overlap → Termination treatment → Acceptance.
Key Operating Points:
(1) Clean the substrate surface, removing dust, sand, and debris.
(2) Before laying, arrange the dimensions on the un-adhesive substrate surface and mark the lines as the baseline for laying the roll material.
(3) Apply primer to the substrate and the roll material's additional layer at joints such as ventilation channels and dividing seams.Allow it to dry for 5-10 minutes at room temperature until it is no longer sticky to the touch,then apply the roll material as an additional layer.
(4) Unroll the entire roll material and lay it flat on a clean,flat substrate to relax the roll material's stress.Lift the roll material from one end and fold it over to the other.Apply primer to the entire substrate and the entire roll material surface,leaving a 100mm gap at the joints.The primer thickness should be uniform,without any exposed areas or gel lumps.Allow it to dry at room temperature for 5-10 minutes until it is finger-dry (no longer sticky to the touch),then apply it.(5) When laying the roofing membrane connecting the flat surface and the vertical wall,proceed from bottom to top,leaving the seams on the flat surface. At corner seams,the membrane should be at least 200mm away from the corner.The short-length seams of two rolls should be staggered by at least 500mm,and the long-length overlap should be at least 80mm.
(6) Air Removal and Rolling:After laying each roll,immediately use a roller to roll it firmly along its long side, starting from one end,to completely remove air and ensure a firm bond.
(7) Joint Treatment:After the main surface is laid,at a point 100mm from where the base coat adhesive has not been applied,flip the joint open and clean the overlap surface with solvent. After the solvent has evaporated, evenly apply joint adhesive to both sides of the membrane joint.Wait approximately 10 minutes until it is no longer sticky to the touch before bonding.Start from one end and gently press the membrane together while squeezing out air.The bonded overlap should be free of wrinkles, bubbles,or other defects. The waterproof membrane roll ends are sealed within the surrounding grooves or below the drip line by the civil engineering unit using cement mortar.
3. Loose-laid method
TPO waterproof membrane loose-laid method construction process:Substrate treatment→Joint reinforcement treatment→Loose-laid membrane→Long and short side overlap bonding→Quality acceptance
(1) Substrate Preparation:The substrate should be flat,firm,and free of standing water. Remove any protrusions from the substrate.
(2) Joint Reinforcement: Reinforce joints according to specifications.
(3) Loose-Lay Membrane:The overlap width of the long and short sides of the membrane should be no less than 60mm.
(4) Long and Short Side Overlap Bonding:Remove the barrier film from the long and short overlap edges of the membrane,then press and bond them firmly with a small roller.
Self-Inspection and Acceptance
During installation,inspect the material continuously.Repair any areas with poor adhesion or sealing immediately. After completion,use a hook to check the overlaps of the membrane for firmness and to identify any hollow spots or weak adhesions,addressing them promptly.No hidden problems should be left unaddressed.The site supervisor and quality inspector must be present during the inspection.
After passing the self-inspection,submit the results to the supervisor and the client for acceptance according to relevant national quality acceptance standards (conducting water tightness/spray tests if necessary).Upon successful acceptance,promptly process the relevant qualification documents.
