There are three main reasons for the hollowing and uplift of the paved floor tiles after one year: the low strength grade of the floor heating filled concrete, the insufficient thickness and the wrong construction of the waterproof layer.
According to JGJ142-2012 "Technical Regulations for Radiant Heating and Cooling" Article 43.Article 1 stipulates: the strength grade of the fine stone concrete filling layer material should be C15, and the particle size of the fine stone should be 5 12mm. The strength grade of the filled concrete of some projects is below C10, the leveling dry hard cement mortar mix ratio when paving the ground brick is 1:3, the paste mortar mix ratio of the pasting ground tile is 1:1, the strength is higher, and the shrinkage stress is easy to "grab" the concrete with low base strength when hardening, and the ground brick hollow drum is formed.
According to the relevant atlas specifications, for the ground radiant heating system, the total thickness of the filled fine stone concrete should not be less than 40mm, and the general design is 50 60mm; The concrete above the epithelium of the heat pipe must be guaranteed to be not less than 30mm. The total thickness of some projects is only 20mm, which obviously does not meet the requirements. During heating in winter, it is easy to cause the floor tiles to bulge and bulge after violent expansion, resulting in rework and rework, especially for the brick-laying floor using the dense joint brick arrangement method.
Bathrooms and kitchens with waterproof requirements must be waterproofed. The waterproof layer should be filled with fine stone concrete after the construction of the leveling layer, and some construction personnel will do the waterproof layer below the floor heating insulation layer, that is, above the base layer, which is unscientific. Once the pipeline leaks, it will stay in the floor heating structure layer and cannot be excluded, which seriously affects the heat dissipation effect of floor heating, and over time, it will produce alkali return phenomenon in the ground tile joints, and form water traces on the ground bricks, which not only affects the appearance, but also affects the use, which is undesirable.
The existing problems of wall plastering and wall tiling are that the masonry of the infill wall is seriously uneven, not vertical, and the thickness of the plastering is uneven. The plastering is super thick and the hollowing is serious, resulting in the paved wall bricks or the same serious hollowing, or large pieces falling off, which requires the construction personnel to strictly follow the specifications, standards and construction technology in the construction of the secondary structure, and operate in strict accordance with the construction technology standards when plastering.
1. Material requirements
Cement: the strength grade is not less than 32For 5MPa ordinary Portland cement, the cement must have a factory certificate, and different varieties of cement shall not be mixed.
Sand: medium sand, average particle size of 035~0.5mm, before use, it should pass through a 5mm aperture sieve, the mud content should not exceed 3%, and there should be no grass roots, leaves and other sundries.
Second, the operating conditions
1) The main structure engineering testing and certification must be carried out by the quality supervision station, supervision and construction unit, and the plastering can only be carried out after passing the inspection.
2) After the roof waterproofing or the upper floor surface layer is completed, the lower indoor plastering operation can be carried out.
3) The formwork at the bottom of the brick wall and floor slab is all removed.
4) The scaffolding eye and construction hole should be filled with the same cement and brick as the original masonry, and the color of the wall should be consistent. The bricks should be filled flat, and the ash joints should be full, and the joints should not be messy. The adjacent damaged bricks should be replaced, the loose bricks should be rebuilt, the exposed steel bar heads, lead wire heads, etc. should be removed, the window sill bricks should be completed, and the junctions of the inner separation wall and the floor slab and the bottom of the beam should be made with oblique bricks.
5) Comprehensively inspect the entire wall with a ruler, repair the serious depression first, and smooth the brick wall and the concrete protrusion of the wall. The honeycomb, hemp surface, exposed ribs, etc. should be eliminated to the real place, brush the plain cement slurry (mixed with 108 glue with 10% water content), and immediately level with 1:3 cement mortar layered to make the entire plastering wall basically flat.
6) Ensure that all embedded parts of door frames, toilet partitions, shelves, window sill boards, water pipes, curtain boxes and other components are not missing and all are installed firmly, and the position and elevation are accurate and have done a good job of anti-corrosion and anti-rust. The weldments of the railings connected to the wall, such as plastic steel windows, aluminum alloy windows, fire doors, and anti-theft doors, must be welded firmly. The ceiling, partition, bobbin and other construction can be carried out only after the construction is completed.
7) The casing should be placed in time when the pipeline passes through the wall hole and the floor hole, and the casing diameter should be two levels larger than the diameter of the pipe used in the design, and the casing should be filled with 1:3 cement mortar or fine stone concrete according to the waterproof requirements; After the installation of the wire pipe, fire hydrant box, louver tuyere, and distribution box should be nailed to the exposed part of the back, and the junction box should be tightly blocked with paper.
8) The door frame plugging should be responsible for a process by a special person, after cleaning with 1:3 cement mortar or 1:1:6 cement mixed mortar layered impaction dense, if the gap is too large, should be mixed with hemp knife impaction in the mortar. Fire doors and anti-theft doors should be filled with fine stone concrete with a strength grade of C20 or cement mortar with a strength grade of M10 in the frame frame, and protective measures should be taken.
Third, the process flow
Watering and moistening Determine the flatness and verticality, make ash cakes, set up standard ribs, make corner protectors, and plaster the bottom and middle layers Plastering window sill boards, window lintels, window covers, bay windows, waist lines, wall skirts and other parts Plastering of the surface layer Cleaning.
Fourth, the operation process
1.Plastering order.
The plastering order is outdoor first and then indoor, up and down first, ground first and then ceiling, then wall and pool squatting platform, indoor first and then corridor and then stairs, and finally steps, scattered water, legs and flower ponds. The dry work must be carried out after all wet work construction is completed, and the wet work shall not be involved in the construction of dry work. In this way, the bond of the ground can be ensured, and at the same time, it is easy to clean to save materials.
2.Moisten with water.
Before plastering, water the wall twice 1d in advance, and the watering method is to move the water pipe slowly to the upper part of the brick surface, so that the water slowly flows down along the wall from the top, and waits until it flows naturally to the foot of the wall, and the wall surface is poured for 1 time;The second repeated operation makes the water seepage depth of the brick wall reach 8 10mm, the concrete water seepage depth reaches 2 3mm, and the aerated concrete block water seepage depth reaches 10 12mm;Wait until there is no water on the surface before plastering. Its purpose is to avoid the mortar from losing its strength due to early dehydration, and at the same time make the mortar bond stable quickly on the surface of the substrate, so that the plastering layer and the wall are firmly bonded. The tools used to load and transport the mortar should be cleaned and watered before use, but there should be no stagnant water. Each shipment of mortar should not be too full, so that it does not spill, does not leak, does not remain, and does not fall. Strengthen the planning of plastering, mix as much as you want, and strictly prohibit the use of overnight ash.
3.Determine flatness and verticality.
In order to ensure the flatness and verticality of the plastering surface, it must be confirmed before plastering. The method is to comprehensively check the flatness and verticality of the surface of the brick wall with the supporting board, and determine the thickness of the wall plastering according to the actual situation of the inspection and taking into account the overall average thickness of the plaster. Then start from the four corners to hang the thread, paste the ash cake, every 12~1.5m wipe 1 100mm wide standard bar as the standard, yin and yang angles, doors and windows on the side of the application of 1:2 cement mortar to wipe the height of more than 2m, width of 60mm corner protection, and the standard bar level, play the role of standard bar, to ensure that the yin and yang angle is square. After the yin and yang corners are plastered, the yin and yang corners trowel should be used for trimming to ensure that the mortar is well combined with the wall.
4.Hardened concrete and cement mortar surface plastering.
Where plastering on hardened concrete and cement mortar, it must be rinsed with water in advance and moistened, and a water-cement ratio of 04~0.5 plain cement slurry (can slightly add 108 glue) bonding layer, cement slurry to brush evenly, there must be no dry spots and puddles, with the brush with plastering. If the base layer is brushed with cement slurry bonding layer too early or the area is too large, when the surface layer is plastered, the bonded layer cement slurry that has been brushed is hard and peeling, not only can not make the base layer and the bonding layer, the surface layer three are firmly combined, but play an isolation role, causing the plastering surface to be hollow; You can also use thick cement slurry (add 108 glue) to process the concrete surface into a rough surface, and then plaster it after it is dry. Flat, smooth and vertical concrete surfaces, if the design does not require, can not be plastered, but only scraped putty.
5.Skirting plastering.
Skirting plastering. The cement baseboard should be carried out on the 2nd day after plastering the wall, and the brick baseboard should be done immediately after the ground is done. The height of the cement baseboard should be about 150mm, and the thickness is generally 8 10mm thicker than the wall. The baseboard plastering should ensure that the wall is consistent, the surface is flat, the vertical deviation and the straightness deviation of the upper mouth are not more than 3mm, and the drum is not hollow.
6.Plastering of the window sill.
Window sill plastering should be prioritized to avoid cavitation. Window sill plastering is divided into exterior window sill plastering and inner window sill plastering, if there is a brick eaves on the external window sill, it should be plastered according to the brick eaves, and if there is no brick eaves, the slope eaves should be wiped out; Most of the inner window sills have window sill plates, if not, use cement mortar to plaster the surface like the outer window sill, and ensure that the window sill surface is smooth and does not pour flooding. The plastering of the slope eaves and inner window sill should exceed the width of the window by 50 60mm, and be plastered to 40mm below the skin of the window sill, and the thickness of the wall should be 10 15mm. The practice of clear water wall and mixed water wall is the same, the specific operation method is: before plastering, check the flatness of the window sill to ensure that it is on the same horizontal line and vertical line with the adjacent window sill, whether the height is consistent with the pick-out, whether the distance between the window sill and the window frame meets the requirements, and the problem should be adjusted in time or corrected when plastering; Then clean the surface of the substrate, sprinkle water and moisten, and use 1:2:4 fine stone concrete to fill the gap of the window lower frame with embedding, and pay attention to ensure that the fine stone concrete is embedded in the groove of the window lower frame to avoid water seepage on the window sill; When plastering the window sill, 1:2 should be used first5. Cement mortar priming, wiping 10mm thick, first wiping the façade, then wiping the plane, then wiping the bottom, and finally wiping the wall; The 2nd D cover, the cover is smeared with 1:2 cement mortar 5 8mm thick, according to the dryness and wetness of the mortar, it can be continuously wiped with multiple window sills, and polished smoothly to avoid water seepage into the room when it rains. Quality requirements: the surface is smooth and clean, the edges and corners are clear, the height of the adjacent window sill is consistent with the picking, the horizontal and vertical are evenly formed into a line, the drainage is smooth, and there is no water seepage. When plastering window sills, window lintels, bay windows, waist lines, pressed roofs, cornices, awnings, balconies, stairs and door and window covers, etc., they should be ensured to be on the same vertical line and horizontal line respectively, and no corners should be channeled. The upper mouth plane should be wiped outward to the slope of the flowing water, and the bottom surface of the lower mouth should be wiped out of the drip line or drip trough, and the depth and width of the drip trough should not be less than 10mm.
7.Plastering of the main beam part.
Before plastering the main beam, the center line of the beam should be ejected in the direction of the beam, and the plastering thickness on both sides of the beam should be controlled according to the elastic line. The bottom surface of the beam should also be hung on both sides of the horizontal line, the horizontal line from the beam head down about 10mm, after the line is straightened, according to the horizontal height of the bottom of the beam and the verticality and flatness of the yang angle, determine the thickness of the plastering at the bottom of the beam. Beam plastering requires square yin and yang angles and straight line angles.
8.Separate column plastering.
The plastering of independent columns should be based on the axis of the column marked in the design drawings, measure the geometric size and position of the column, bounce the center line of the two directions perpendicular to each other on the floor, and release the column edge line after plastering, and use a short ruler and line drop to check the verticality and flatness of each side of the column. If it is not out of tolerance, make a sign block at the four corners of the column about 150mm away from the floor and the ceiling; If the cylinder surface is out of tolerance, it should be processed, and then the flatness and verticality should be determined, and the marker block should be made. If there are two or more columns, the line should be pulled through to make the marker block. When plastering the column, it is necessary to check the vertical and flat up and down of the cylinder, the corners are square, and the shape is consistent and neat. The plastering of brick pilasters should pay attention to the consistency of each brick pilaster, and the yin corner of the junction with the wall should also be vertical and flat, and the yin corner should be straight when plastering.
9.Staircase plastering.
Before plastering the stairs, in addition to cleaning the stair treads, railings and other substrates, the embedded parts such as steel and wood railings and handrails should be filled with C20 fine stone concrete. The size of the stair tread in the structural construction stage must have some errors, so it is necessary to pay off the line to correct, and its method is to play a step step standard line on the side wall of the stair and the railing according to the platform elevation and the floor elevation, and when the plastering operation, it should also be noted that the step height and the step width size of each tread are consistent, so that the position distance of the yang angle of the tread on the standard oblique line is equal. The plastering must be plastered first and then the plane, the bottom surface of the tread board should be wiped with a drip line, and the end of the tread board should be wiped with a water line.
10.Maintenance.
All cement mortar plastering walls must be watered and cured for more than 7 days from the second day after plastering.
Fifth, quality requirements
Master control project: Take intermediate plastering as an example, plastering should be repeated at least 3 times. With 1:2 cement mortar as corner protection, its height should not be less than 2m, and the width of each side should not be less than 50mm. The average thickness of the wall plastering layer is 20mm, and the thickness of each plastering is 5 7mm, which requires a smooth and clean surface, smooth and smooth jointing, clear and straight four corners and eight lines, and the vertical deviation of the wall and the yin and yang angles shall not exceed 4mm, and the flatness of the wall shall be checked with a 2m long ruler, and the deviation shall not exceed 4mm. The bond between each plastering layer and between the plastering layer and the substrate must be firm, without delamination, hollowing, and no defects such as ash blasting and cracks in the surface layer.
General items: smooth and clean surface, uniform color, no wipes, straight and square, clear and beautiful with four corners and eight lines; The plastering behind holes, slot boxes and pipes is neat, smooth and flat; The gaps between the corner protection, door and window frames and walls should be filled with dense and smooth surfaces; The exterior wall grid lines are consistent in width and depth, flat and smooth, neat in edges and corners, and smooth horizontally and vertically; The slope direction of the drip line and the groove flow is correct, the drip line is straight, the depth and width of the groove are not less than 10mm, neat and consistent, and the doors and windows are square.
6. Safety precautions
Before operation, the ground should be cleaned, check whether the scaffolding or high stool is firm and stable, the scaffold shall not leave a probe board, the scaffold board shall not be less than two, and its span shall not exceed the relevant provisions and shall not be overloaded; The ash bucket should be dispersed and smoothly arranged on the scaffolding. It is forbidden to place wooden benches and ladders on the scaffold for operation, if the height of the scaffold is not enough, it should be re-erected, and it is strictly forbidden to erect a flying springboard.
Excerpt from ".Construction workers, Gu Shujun