The main factors affecting the quality of stone dry hanging are as follows.

1, the skeleton is firmly installed, the surface flatness of the skeleton is properly controlled, and the anticorrosion, rust prevention, lightning protection and grounding treatment are well done.

2, dry hanging marble surface and skeleton installation is firm; Paste materials, dry hanging accessories meet the design requirements; Steel fittings should be well protected against rust and corrosion.

3. The stone surface is clean and smooth; Correct spelling, clear texture and uniform color; Non-whole-board parts should be installed, slate at internal corners should be pressed, and slightly damaged stone materials should be repaired.

4. Joints should be uniform, smooth, plugged and uniform in width.

5. The plates around the protrusions are cut by the whole plate, with accurate dimensions, neat and smooth edges, straight drip line, correct slope direction of running water, and clear and beautiful appearance.

Second, the application process quality control

(A) the construction process

1. Selection of stone materials: wall framing, layout, selection, processing and numbering of stone materials.

2. Dry hanging process flow: external wall base treatment-wall framing and setting out-adding numbers to the steel skeleton-installing and fixing the steel skeleton-checking and adjusting the flatness and firmness of the skeleton-making stone dry hanging formwork-large-area dry hanging stone-stone surface cleaning-embedding sealing strips and sealants-decorative surface cleaning-acceptance.

(2) Construction method

1. Preparation of facing stone: The color difference of stone is one of the most important factors affecting the appearance of dry-hung stone. And what are the factors that cause the color difference of stone?

(1) The vein is different. There must be color difference in stone platforms mined from different veins, which is also the most important factor to produce color difference of stone.

(2) The cutting surface of stone is different. After the stone mine is mined, if the cutting surfaces are different, it is easy to cause the phenomenon of yin and yang on the surface of a single stone, or the two slabs cut from the same stone mine are very different.

(3) Stone cutting time is different. Due to the different cutting time, the surface color of the stone cut by the same ore will be different, but this color difference can tend to be the same with the passage of time.

For the above reasons, stone suppliers should make an evaluation in advance. But in any case, the subtle color difference on the stone surface still exists. Our approach is to choose more powerful suppliers to ensure that the supplied stone materials can come down in one continuous line, and most of the stone materials are directly processed and molded by manufacturers. According to the setting-out of external wall frame, the site is divided into dry hanging area and area. After the stone material arrives at the site, it shall be laid out first, and the installation position of the stone material shall be determined before numbering. Stone with slight chromatic aberration should be arranged in the position of internal angle and other places that will not affect the overall appearance as far as possible in advance.

2, external wall base treatment and frame lofting

(1) Basic treatment: Basic treatment is generally to align and clean the embedded steel plates of the external wall, and check whether the embedded steel plates are located correctly. If the embedded parts are found to be offset, they should be reinforced. At the scene, we used the rear anchor bolt steel plate to reinforce it. After the installation is completed, the next working procedure can only be entered after passing the drawing test.

(2) Setting-out by frame: Setting-out work is the basis of back keel installation, so we specially prepared a set of setting-out plan and established a perfect review system.

A, horizontal control line: use the 0.000m elevation line of the level guide as the main datum line, and then set the horizontal datum line in units of floors. Horizontal framing starts from the top of the external wall, and takes the dry hanging height of two plates as framing unit from top to bottom, and fine-tuning is carried out by using each layer of baseline to eliminate errors.

B. Longitudinal control line: First, systematically measure the deviation of the original structure and analyze the deviation between the actual size and the design size. If the actual size deviation is relatively small, the error can be eliminated by reasonable framing, otherwise the structure needs to be treated.

Use theodolite to set a longitudinal datum line on the external wall of the building every 20m. According to the frame size (based on the width of two boards), the external wall of the building is vertically framed, and the distance between the upper and lower points and the baseline is measured with a plumb line, and then the deviation is corrected. The vertical control line and the horizontal control line constitute the plane control network of our pay-off, as shown in the figure below.

3, keel installation quality control

The installation quality of keel directly affects the dry hanging effect of stone. Weak keel installation is likely to cause safety hazards. If the keel is not installed on a plane, it is easy to cause defects such as stone distortion and unqualified flat-fell seam in the subsequent process. Therefore, we make full use of our predecessors' QC experience to establish a three-level control network from the installation of the main keel to the installation of the secondary keel and then to the quality control of the stone veneer installation.

(1) Primary control network: find out the embedded parts and determine the model and position of the main keel. Determine the model and specification of the main keel according to the skeleton, and number the keel to ensure that there is no deviation in the used parts of the processed keel. When the main keel is installed, it should strictly correspond to the frame lines and be controlled by stay wires to ensure that the installation keel is on the same plane. After the installation is completed, assign special personnel to check layer by layer, and make monitoring records.

After the main keel is installed, it should be treated with anti-corrosion and anti-rust in time. The lightning protection grounding of this project adopts the method that each layer is welded to the vertical keel with galvanized flat iron, and then welded to the lightning protection grounding point of the wall and beam. After the acceptance of the previous procedure is completed, proceed to the next procedure.

(2) Secondary control network: determine the model and position of the secondary keel, after the installation and acceptance of the main keel, lead the transverse frame line to the main keel, draw a line, and install the secondary keel according to the played line; Secondly, it is required to measure the actual size of the secondary keel on site, then add the secondary keel according to the actual size and install it according to the number. Third, when installing the secondary keel, it is required that the top surface of the secondary keel is straight, and the outer side is controlled in the same plane as the column, and a small part can be fine-tuned. Finally, after the installation of the secondary keel is completed, the team will conduct self-inspection and notify relevant personnel for acceptance in time.

One end of the secondary keel is a telescopic end connected by bolts, and the other end is a fixed welding end. Welded joints must be treated with anti-corrosion and anti-rust.

4. Quality control of external wall stone dry hanging

Stone dry hanging is the last level in the three-level control network, and this process directly affects the sensory effect of the decorative surface of stone dry hanging in the future. Therefore, we adopt the principle of applying the template first, choose the appropriate position as the template, carry out some dry hanging operations of stone materials, and continuously improve the construction technology according to the effect of applying the template.

(1), process

First of all, we plan carefully in advance and establish a plane control system for plate installation: take every four plates as a small unit for dry hanging control.

Secondly, the stone installation sequence: make a work plan, and strictly require the team to start from the main facing, from top to bottom, and from left to stone in turn (note: some units also adopt the dry hanging sequence from bottom to top and from left to stone). The first row of dry hanging stones is used as the facing of benchmark stone (the facing of benchmark stone is the guarantee of stone building quality). If you can't make the finished surface according to the design, it will easily become a crevasse, inclined wall or wave shape, which will destroy the overall effect. In the dry-hanging project, personnel will be arranged to stand by and supervise, and the dry-hanging construction of the next row of stones can be carried out only after the unified acceptance is completed.

(2) Temporary fixation of plate: During installation, the lower end of the component is in a fixed state and the upper end of the component is in a temporary state. Inject adhesive into the hole at the lower end of the stone and insert the stainless steel gasket prepared in advance to fix it (note: iron parts are easy to corrode and pollute the stone surface, and the flexible gasket will cause the stone to shift), and then proceed in turn, and the stainless steel gasket can be taken out after the glue dry fixing is completed.

(3) Details processing

A, detail stone should be the whole plate cutting, shall not use scattered scraps for assembly. The required plates shall be measured, cut and installed on site. The stone blank holder is correct in the window opening position, which can be controlled by setting the slope of running water, leaving drip line and groove.

B, the dry hanging plate around the detail should be installed and fixed accurately, and the prominent part should be polished in time to ensure horizontal and vertical. For slightly damaged stone, choose to install it in an inconspicuous corner and repair it with original stone powder mixed with special stone glue.

5, stone seam washing and gluing process control

(1) After the installation of the cushion stone, it is necessary to wash the joints at local positions to make the longitudinal and transverse joints look more uniform and straight and increase the decorative effect.

(2) After the stone dry hanging construction is completed, clean the surface and remove the dust in the gap. First, the solid board is filled with foam plastic strips with a diameter of 8- 10 mm, leaving a seam with a depth of 5-6 mm, and adhesive tapes with a width of 10- 15 mm are attached to the stones on both sides of the seam to prevent the board surface from being polluted during gluing and caulking. Then fill the sealant with a glue gun. If sealant is found to pollute the board surface, it must be wiped immediately. At the position of the window, first plug the foam stick along the gap of granite slate, and then select high-quality sealant to glue, and the depth of glue joint is 15 mm, and finally use it? 10 plastic rod is pressed out of concave circle. After application, the waterproof performance of the wall is tested by sprinkling water on the wall. At the same time, in order to make the gluing surface look continuous and smooth, skilled workers should be specially selected to operate.