Roof leakage is a common problem in construction engineering. We believe that to ensure the quality of waterproof engineering, design is the prerequisite and construction is the key. It is also necessary to choose a suitable waterproof material (especially in Shenzhen, the temperature is high, the solar radiation is strong, and the rain is much, the choice of waterproof material is more important).
I. Design requirements for roof slope
Slope is the primary basis for roof drainage and waterproofing. At the same time, the drainage area should be divided according to the location of the drainage openings in the roof design. Generally, the horizontal width of the house surface is taken as the centerline of the ridge, the balcony is opposite the sink and the slope is reversed, and the area is divided between the two sinks in the longitudinal direction. The drainage slope is between 2% and 3%, which can reduce the water ills of the house area.
Second, choose the right waterproof material
The selection of waterproof materials has a great impact on the quality and durability of the waterproof layer. Correct selection and reasonable use of waterproof materials is one of the keys to the success of roof waterproof design. Although there are many types of flexible waterproof materials at present, their performances are different. Asphalt coils have poor puncture resistance, low temperature flexibility, easy ageing, and short durability of the waterproof layer. The PVC modified asphalt coil has aging resistance, weather resistance, large elongation and long service life. At the same time, the construction is simple, the cost is low, the maintenance is convenient, and the use effect is good.
The performance requirements of PVC waterproof membrane are: tensile strength: longitudinal ≥7.0MPa, transverse direction 1> 7.0MPa. Elongation at break: 150% in the longitudinal direction and 150% in the transverse direction. Tensile force: ≥7O in the longitudinal direction, ≥6O in the transverse direction, heat resistance of 90 ° C, low temperature bending property: -20 ° C, no cracks. Impermeability: O. 2MPa, impervious to water for 24 hours, impervious to water.
Third, the quality control of cement mortar leveling layer
The screed layer is the base layer for laying the waterproof layer of the coiled material, and provides the waterproof coiled material with a flat, dense, strong and adhesive structural foundation. When the base layer is monolithic concrete, a cement mortar screed layer is used with a thickness of 20mm and a cement-to-mortar ratio of 1: 2.5-1: 3 (volume ratio). Sealing material is embedded, so as to avoid or reduce cracking of the leveling layer, so that when the structure is deformed or the temperature difference is deformed, the waterproof layer will not form cracks, which will cause leakage. No more than 6m, the position of the partition seam is set at the branch end of the roof, the junction of the waterproof layer at the corner of the roof and the protruding roof member, the junction of the waterproof layer and the daughter wall, etc. And it should be aligned with the end seam of the board, even and straight.
When the cement mortar leveling layer is used for construction, first clean up the debris from the roof slab and wet it with water. When laying the mortar, follow the procedure from far to near and from high to low. It is continuously laid once in each division, the slope is controlled according to the design, and it is smoothed with a scraper rod with a length of more than 2m. After the mortar has slightly received water, Use a trowel to compact and smooth it. After 12 hours, cover it with a straw bag and water it for curing. For protruded roof structures and detailed nodes such as pipe roots, arcs, truncated cones or square truncated cones should be made, and made of fine stone concrete to avoid cracking of the coils at the joints, which is conducive to stickiness.
(1) Water drop mouth: It is made within 500mm, the slope is ≥5%, and it is smooth.
(2) The roots of the daughter wall, the roof flue and the stairwell are made into arcs with a radius of 80 mm and made of fine stone concrete.
(3) Extend out around the root of the roof pipe and make a square cone table with a fine stone ballast. The bottom surface of the cone table has a width of 300 mm and a height of 60 mm.
Fourth, the construction and paving of PVC coils and quality requirements
1. Before laying PVC membranes, check whether the quality of the leveling layer meets the requirements, so that the base layer is solid, flat, dry and free of debris and soil. Especially when the base layer is wet, if the waterproof material is laid, the coil material will not lay firmly, and there will be water seepage, which will cause the waterproof effect to fail.
2. The direction of coiling materials shall be parallel to the roof ridge. The overlap seams of the parallel ridges shall be overlapped in the direction of the flowing water.
3． Brushing the surface of the base layer: Apply evenly a layer of about 1 mm thick adhesive on the dry base layer (when the binder is too thick or too thick, heat slowly with gentle heat, and the temperature should not be too high). -Roll back and forth everywhere, so as not to "bite" the primer, forming a gel and affecting the quality. When applying the base adhesive, special attention should be paid to yin and yang corners, corners of flat elevations, coil ends, drainage outlets, and other joints such as the roots of roof pipes.
4． Laying of coils.
When constructing the rolled material, first use the ink line to stretch the control line on the screed, and then construct from the cornice (lower elevation of the roof) to the roof ridge. Align the rolled material with the stretched powder line. Overlap width lines pop up on the material. When laying a roll of material, re-roll it with a 50 mm-100 mm plastic tube, with the adhesive-coated side facing outward, and roll it through a central plastic tube with a 30 mm x 1500 mm steel tube after rolling. Hold the steel pipe at both ends, lift the end of the coil, align the powder line, unroll the coil, and make the coil flat. When applying the second roll, align it with the control line. After each roll is rolled, immediately use a clean and soft long-handed pressure roller to roll from the end of the roll in the order of the roll in the transverse direction to completely eliminate the roll. The air between the bonding layers is rolled from the middle to the two sides to exhaust the air completely. After the coil is laid and pressed, the edge is sealed with an adhesive. The edge must be firmly bonded, tightly sealed, and uniform, continuous and fully sealed.
5. Handling of roof joints and special areas.
The roof node is an important part of waterproofing. Good handling has an important effect on the waterproofing of the entire roof. Therefore, special attention should be paid to the waterproofing of the details, so that the additional layers of the details are not exposed, and the position of the joints is smooth and reasonable.
① Treatment of water drop.
Water-proof coating is used as an additional layer with a diameter of 500mm around the water-fall opening. The thickness is> 2mm. Spread the layers of coils and additional layers to the water-fall opening. Use scissors to cut across the line with the same length as the diameter of the water-fall. On the mouth, the bottom of the rain cover is used to press it tightly, the base plate and the coil are bonded with an adhesive, and the base plate is sealed with a sealing material around the periphery.
② Treatment of sticking out of the roof pipe.
The leveling layer at the root of the pipe is made into a truncated cone. A groove of 20 mm × 20mm is reserved between the pipe wall and the leveling layer. It is embedded with a sealing material, and then an additional layer is laid, followed by a waterproof layer, and an adhesive for the coil interface. Sealed and tightly clamped by metal bead.
③ Flooding construction treatment.
The corners of the surface and the vertical wall are called flooding. For the waterproof treatment, a waterproof additional layer is added first, the width of which is 250 mm on the elevation and the plane, and then the plane and the corner are paved, and then paved from the bottom to the top. The facade coils are rounded at the corners. The daughter's wall was cut and flattened, and pressed with bead nails, the nail pitch was evenly ≤80 mm, and then painted with a waterproof cold glue. The base layer at the yin and yang corners is glued with a sealing paste and then sealed with a sealant paste at a distance of 100 mm from the corner edge, and then an additional layer of coil material is laid, and the cut seam is sealed with a sealing paste after paving.
Fifth, the insulation layer to the roof waterproof membrane protection
After the waterproofing membrane is finished, it must be protected to avoid affecting the waterproofing effect. Lay a 300 film × 300 ml / l expanded perlite insulation block on the waterproof layer, and then add a layer of 3 cm thick cement mortar protection layer on it. This layer is lined with steel wire mesh, and the protection layer is set with grid joints. The seam is filled with sealing material to better protect the waterproof layer.
Six, matters needing attention in roof waterproof construction
1. It is strictly forbidden to apply coils and insulation on rainy days.
2. The leveling layer of the waterproof layer of the coil should meet the quality requirements and achieve the specified dryness.
3． At roof corners, gutters, water drops, roof ridges, coil overlaps, and ends, nodes should be carefully flattened and compacted, compacted, securely closed, in accordance with relevant requirements such as design requirements and roof engineering technical specifications. Corners, gutters, water drops, roof ridges and other parts should be added with additional layers of coiled material.
4． To avoid excessive tensioning and wrinkling when laying the coiled material, the base layer and the coiled material should be fully vented. After venting to the lateral sides, use rollers to flatten and stick.
5. The overlap width and paving of the coiled material should be straight, and construction should be carried out in strict accordance with the marked lines at the grassroots level.
6. Protect the waterproof layer when laying the insulation layer.
Roof waterproofing project is an important project of house construction. The quality of the project directly affects the life of the building and the production and life of the owner. Therefore, we should pay attention to the roof waterproofing project. If you want to know more, you can consult Shaanxi Zhonghong Pipeline Company specifically. Tel: 029-89395188