1. Project Overview
The conventional mechanical fixing system,i.e.the TPO waterproofing membrane,uses fixing screws,conventional fixing gaskets or sleeves to fix the waterproofing membrane (layer) system on the roof in a point-fixed manner,and can withstand all external loads (wind loads,shrinkage deformation loads,etc.) to ensure the waterproof enclosure function of the TPO single-layer roofing system.
The conventional mechanical fixing system structure of the steel structure TPO waterproofing insulation roof is as follows from top to bottom:
(1) 1.5mm thermoplastic polyolefin TPO waterproofing membrane (conventional mechanical fixing)
(2) 80mm rock wool insulation board (double-layer staggered laying)
(3) 0.3mm (PE) vapor barrier membrane
(4) structural corrugated steel plate base
TPO membrane waterproof insulation roof construction process diagram
2. Construction tools
(1) Automatic hot air welding machine
Applicable to flat large-surface TPO coil seam welding.
Automatic hot air welding machine
(2) Handheld hot air welding machine
Use handheld hot air welding machine to weld the detailed joints of TPO coil.Handheld silicone rubber roller is used in combination with the welding machine to apply pressure to fuse the heated coil surface together.
Handheld welding machine is usually used when repairing seams or when it is not appropriate to use automatic hot air welding machine (such as in pipeline penetration or on high slope surface).
Handheld hot air welding machine
(3) Silicone roller
Two types of silicone rollers with 20mm and 40mm width are used to roll hot air welding seams,of which 20mm wide silicone roller is used for rolling detailed welds.
(4) Electric screwdriver
Electric screwdriver with power greater than 600W,used to tighten screws.
(5) Other special small hand tools
Including special trimming knives,hook knives and other matching special small tools for TPO welds.
3. Construction technology
3.1 TPO waterproofing membrane construction process
Preliminary preparation → base treatment → vapor barrier layer → mechanical fixing insulation layer → mechanical fixing membrane → hot-melt welding membrane → detail node treatment → completion acceptance
3.2 Construction methods and operation requirements
3.2.1 Construction preparation
(1) Material preparation
Before construction,the membrane and system supporting materials should be fully prepared;and the quality should be checked to see if it meets the relevant standards.Sealant paste and cleaning agent should be stored in a cool and dry warehouse,equipped with sufficient fire-fighting equipment,and avoid exposure to sunlight.Do not damage the original packaging of TPO membrane,and store it in a cool place and cover it.
The insulation board should be stacked on a flat and dry site in the warehouse,stored in a higher place,and covered with waterproof and breathable canvas to avoid rain and rain soaking.
3. Construction technology
3.1 TPO waterproofing membrane construction process
Preliminary preparation → base treatment → laying vapor barrier → mechanical fixing insulation layer → mechanical fixing membrane → hot-melt welding membrane → detail node treatment → completion acceptance
3.2 Construction methods and operation requirements
3.2.1 Construction preparation
(1) Material preparation
Before construction,the membrane and system supporting materials should be fully prepared;and the quality should be inspected to see if it meets the relevant standards.Sealant paste and cleaning agent should be stored in a cool and dry warehouse,equipped with sufficient fire-fighting equipment to avoid exposure to sunlight. Do not damage the original packaging of TPO membrane,and store it in a cool place and cover it.
The insulation board should be stacked on a flat and dry site in the warehouse,stored in a higher place,and covered with waterproof and breathable canvas to avoid rain and soaking.
3.2.2 Base treatment
Before construction,the construction project department should inspect the base to ensure that the base meets the requirements for laying TPO membrane.The corrugated steel sheet of the TPO roll roof system must be reliably connected to the main structure and able to withstand the wind load on the roof.The connection between the corrugated steel sheets should be smooth and continuous,and there should be no sharp protrusions to avoid piercing or cutting the vapor barrier and the roll.The corrugated steel sheet roof node method should comply with the design and relevant national standards. Before laying the roll,remove the debris and foreign matter on the base.
Before laying the roll material, remove debris and foreign matter from the base
3.2.2 Base treatment
Before construction,the construction project department should inspect the base to ensure that the base meets the requirements for laying TPO rolls.The corrugated steel sheet of the TPO roll roof system must be reliably connected to the main structure and able to withstand the wind load on the roof.The connection between the corrugated steel sheets should be smooth and continuous,without any sharp protrusions to avoid piercing or cutting the vapor barrier and the coiled material.The corrugated steel sheet roof node method meets the requirements of the design and relevant national standards.Before laying the coiled material, remove the debris and foreign matter on the base.
The steel structure roof of this project adopts the YX35-125-750 plate type.After entering the site,the laying of the corrugated steel sheet on the roof base should be checked,including the laying direction of the steel sheet,the lap edge treatment,the number and tightening degree of the screws connecting the corrugated steel sheet and the purlin,etc. Construction can only be carried out after meeting the requirements.
Schematic diagram of overlapping vapor barrier layer (PE film)
2.2.4 Mechanically fixed insulation layer
(1) The rock wool insulation board of this project is mechanically fixed and installed. According to the design requirements of different single-unit drawings,the roof plane adopts double-layer staggered laying of 50mm thick rock wool insulation board to avoid the formation of through seams that affect the insulation effect. During the laying of the insulation board,pay attention to the tight and flat overlap.The rock wool installation and subsequent roll material construction should be carried out simultaneously to prevent water and moisture. If the edges and corners of the board are damaged,they should be cut neatly before laying.
Rock wool insulation board staggered laying
(2) According to the requirements of the specifications,the number of rock wool insulation board fixings for this project is 2 per board,and the fixing position of the insulation board should be strictly determined according to the figure below:
Note:Applicable to 0.6m×1.2m rock wool insulation board,it should be fixed according to the position in the above figure.When the position of the insulation board fixing coincides with the roll material fixing,the insulation board fixing is cancelled and the position of the roll material fixing is given priority.
Use special insulation sleeve to fix the rock wool insulation board
(3) The screws must be anchored at the crest of the corrugated steel sheet.During the tightening process,the screws should always be perpendicular to the corrugated steel sheet.The tightening degree should be appropriate.Over-tightening or under-tightening will seriously affect the wind resistance of the roof system.For a softer insulation layer,appropriate tightening can see slight compression deformation around the sleeve.It should be ensured that the sleeve does not cause cracks on the surface of the insulation board.The fixing screws should penetrate the corrugated steel sheet and expose at least 25mm of the corrugated steel sheet.
2.2.5 Laying and fixing of coils
The first coil is laid out. During construction,the coils must be pre-laid first.When using a corrugated steel plate base, the laying direction of the coils should be perpendicular to the corrugation direction of the corrugated steel plate.The naturally loose coils are arranged on the base according to the contour,flat and straight,and must not be twisted.The overlap width of the long side of the coil is 120mm,and the overlap width of the short side of the coil is 70-80mm.The actual spacing of the fasteners is determined according to the wind load calculation results and the steel plate type.During installation,pay attention to ensuring that the fixings are straight.The distance between the screws and the edge of the coil is 30mm,and the error does not exceed 10mm.
Conventional mechanical fixing system coil fixing diagram
After the coils are laid and unfolded,they should be placed for 15-30 minutes to fully release the internal stress of the coils and avoid wrinkling during welding.
Lay adjacent coils and form a 120mm overlap along the length of the coils.The hot air welding width is at least 40mm.
The fixings at the periphery and corners of the roof should be encrypted.The encryption method is determined according to the width of the coils and the spacing between the fixings.In addition,gaskets or pressure strips are required to fix the roll material at skylights,expansion joints, roof pipes,etc.
2.2.6 Hot air welding
(1) Use an automatic hot air welding machine or a handheld hot air welding machine and a silicone roller to hot air weld the TPO waterproofing membrane.When the roof slope is large and it is inconvenient to use an automatic welding machine,it is recommended to use crawling welding or a handheld hot air welding machine.When the operating space of the roof detail nodes is small and it is inconvenient to use an automatic welding machine,it is recommended to use a handheld hot air welding machine and a silicone roller in combination.
Automatic hot air welding machine
(2) Cleaning of aged membranes
After the TPO membrane is contaminated or exposed to the external environment for about 7 days,it must be cleaned before hot air welding:wipe the contaminated membrane overlap with a damp cloth to remove dust and other debris,then clean the welding area with clean water (neutral detergent can be used for severe contamination),then wipe dry with a clean rag, thoroughly clean with a special membrane cleaning agent,wipe dry with a white rag, and wait for the membrane cleaning agent to completely evaporate before welding.The welding speed should be about 20% slower than the normal welding speed.
(3) Temperature setting
When using an automatic welding machine,set the welding temperature to about 450-550℃.The welding temperature and speed are determined by the ambient temperature,wind force,and coil temperature.Before officially starting welding every day or after a sharp change in temperature,a trial welding must be performed to determine the optimal welding temperature and speed.
(4) Coil welding
① Prepare the hot air welding machine and preheat it for about 5-10 minutes to reach the working temperature. Mechanically fix the overlap on site,the minimum overlap width is 120mm,and ensure a welding width of at least 40mm.
② Put the automatic hot air welding machine in place before the seam,and guide the fingers in the same direction as the machine moves along the seam.
③ When lifting the overlapped coil,insert the air nozzle of the automatic hot air welding machine into the overlap area. Immediately start moving the machine along the seam to prevent burning of the coil.
④ When working along the seam,ensure that the small guide wheel at the front of the machine is aligned with the edge of the upper sheet of coil,and ensure that the cable is long enough to prevent the machine from being pulled off the running track.
⑤ At all seam intersections,use a silicone roller to roll the seam to ensure a continuous seam of the hot air weld.The surface irregularities caused by the multi-layer thickness of the TPO coil may cause false welding.When using 1.5 mm thick TPO coil,the surface overlap of the TPO non-enhanced flashing must be located above the overlap intersection of all "T" joints.
⑥ After completing the seam welding,immediately remove the automatic hot air welding machine nozzle from the seam to avoid burning the coil.
⑦ Ensure that there are no wrinkles in the hot welding area,and the wrinkles in the overlap area must be cut off. When welding in the area between the stop and restart of the automatic hot air welding machine,a handheld welding machine is required.
(5) Handheld welding machine settings
① The temperature of the handheld welding machine should be set to "6" when used for flashing welding.
② The temperature of the handheld welding machine should be set to "8" when used for coil welding.
③ The silicone roller should always be rolled along the direction perpendicular to the weld seam or flashing of the coil.
(6) Seam inspection
After the weld has cooled,use a flat-blade screwdriver to check all welds to ensure that there is no leakage.If defects are found,use a handheld welding machine to repair the weld defects.
After the seam detection is completed,use the trimming sealant to seal all trimmings of the reinforced coil.
(7) T-joint treatment: By arranging the coils reasonably to avoid cross joints,the number of joints can be reduced so that all welds are straight welds or T-joints:When three layers of coils overlap each other,T-joints will be generated.To avoid the situation of loose welding when the coils overlap each other,the following treatment is required: When the coil thickness is ≥1.5mm,the coils at the T-joint need to be cut and the front end of the weld is cut into an inclined surface with a trimming knife to eliminate the different heights caused by the overlap of the coils and achieve the effect of cleaning the boundary of the joint line to ensure the welding effect.Cut a 150mm diameter homogeneous TPO coil and weld it to the T-joint. First spot weld it and then weld it firmly around. Welding is the most important technical guarantee for the construction of TPO waterproofing coils,especially at the T-joint. If the welding is not dense,many capillaries will appear, which will cause leakage during future use.
3.2.7 Detailed node processing:
(1) Coil closing:The TPO waterproofing membrane should be closed with professional closing strips and screws,and sealed with sealant. The corners,gutters,water outlets,skylights and other parts can be constructed according to the post-attached nodes.If the post-attached nodes are not suitable for the actual project situation,the construction technicians should contact the design unit,the owner and other relevant units in a timely manner to determine the detailed practices according to the actual situation on site.
(2) External gutter traditional construction method node:The bottom of the gutter is fixed with two U-shaped strips and screws.After penetrating the membrane,the PMT-3010 homogeneous membrane is cut into 150-200mm wide and covered on the fasteners.The surroundings are welded with the large-surface membrane to form a complete waterproof system.The welding machine tool is placed directly on the membrane covering the special coating gasket, and the bottom of the membrane is welded to the top of the gasket.The magnetic cooling pressure suppressor is placed on the gasket to enhance the welding effect.
(3) Parapet walls,skylights,roof openings,high and low spans and other places where the horizontal and vertical surfaces meet should be constructed using different methods based on the vertical elevation.
(4) Sealing treatment of fans,skylights,and pipes exiting the roof:
Confirm the sealing position after communicating with the lighting and fan construction units,and use sealing strips,sealing screws,and sealants.It can be sealed on the plane or facade.It is recommended that the waterproof membrane construction unit complete the sealing before subsequent lighting and fan installation.The sealing position must be a rigid and non-shrinkable solid base,such as a steel plate of 0.8mm or more.
(6) Treatment of the node of the roof pipe
Cut a piece of homogeneous TPO waterproof membrane with a length of the membrane flip height + 20mm and a width of the pipe circumference + 30mm,and heat and stretch the junction of the membrane and the large surface membrane.
(7) Siphon rainwater outlet node
The siphon rainwater outlet node involves siphon rainwater buckets,screws,pressure plates,rubber pads, etc.,which are provided by relevant professionals.The specific shape and specifications are subject to actual conditions.
(8) Ridge node
(9) Inspection and acceptance
① The detailed structures such as the ridge,parapet,roof opening,and roof facilities should meet the design requirements.
Inspection method:Observation inspection and measurement inspection.
② The lap joints of the waterproof membrane must be tight.
Inspection method:Hot air welding lap joints can be visually inspected. A hook or flat-head screwdriver can be used to pick along the edge of the weld. If there is no leakage,it is qualified.
③ The specifications,layout,location and quantity of the waterproof membrane and insulation board fixing parts constructed by mechanical fixing method should meet the design requirements.
④ Inspection method:Observation inspection and measurement inspection.
