In building decoration, curtain walls are decorated. The curtain wall is a decorative wall surrounding the periphery of the main structure of the building. In China’s curtain wall decoration, many decoration building materials are stone. After all, the stone curtain wall is working at height, and the construction is difficult. In this article, we will analyze these construction difficulties.
● Treatment measures for joints of different curtain walls
Different curtain wall joint treatment is also the construction focus of the project. The treatment measures of different curtain wall joints are based on the design drawings: filling foam rods into the gaps and sealing sealant. The rubber surface shall be flat and smooth.
The interface between stone and window is a special part. Therefore, the position involves the contact between stone and aluminum materials, and waterproof is particularly important here. Therefore, in the contact area between windows and stones, a foam waterproofing agent is first filled inside to ensure the waterproof performance of the interface. After the foam is dried, the silicone rubber weatherproof glue with excellent properties will be used to fill the gap between stone and window to ensure that the gap is not permeable and has good waterproof performance.
● Stone slotting
Stone slotting is an important key process. To control the quality of this process, the first is to ensure that the equipment is in the optimal working state, and the second is to select serious, responsible and experienced operators for operation. Finally, it shall be tested by slot by slot, and those that do not meet the process requirements shall be discarded, ensure the safety of the stone curtain wall. When the steel keel is installed, a stone slotting machine shall be used for on-site emergency stone plate slotting.
● Key points of steel structure construction
The anti-corrosion of steel structure is the focus of construction. The steel keel of the stone curtain wall is hot-dip galvanized. Hardware fittings are made of stainless steel. When welding on-site, the welding parts must be subject to anti-corrosion treatment, and the thickness of galvanized coating shall not be less than 75um. Steel corner codes and connectors shall be hot-dip galvanized. During the coating construction of exposed steel frame, the construction shall not be carried out under the conditions of construction, rain, and fog (especially the surface coating, construction is strictly prohibited). The environment shall be clean, and the surface must be dry without moisture. The temperature shall not be lower than + 15 ℃, and the relative humidity shall not be greater than 60%. Pay attention to the change of climate conditions during construction. In case of strong wind, rain, and fog, construction is not allowed (especially for surface coating, construction is strictly prohibited)
● Curtain wall construction survey
The measurement of the curtain wall grid axis shall be coordinated with the measurement of the main structure, and the error of the main structure shall be adjusted in time to ensure that the processing and manufacturing meet the actual situation on site; The measurement shall be carried out when the wind force is not greater than grade 4, and the position of the curtain wall shall be checked regularly every day.
● Curtain wall waterproofing
The rational design of the curtain wall profile is one of the important waterproof measures. The profile is designed as a pressure balance system. According to the rain curtain principle, a guide hole for external pressure to enter the interior is preset on the curtain wall profile, to adjust and balance the internal and external pressure difference and achieve the purpose that external water is not easy to enter. At the same time, drainage holes are opened at the outer edge and lower part of the profile to drain a small amount of water seepage or indoor dew. The above waterproof and drainage measures together form a dry sealing system. On the one hand, it is not easy for water to enter the interior of the curtain wall, on the other hand, even if there is water infiltration, it will be automatically discharged. When presetting holes, two holes shall be set on each transom, about 100mm from the corner, and the horizontal distance between the upper and lower holes shall be greater than 50mm to prevent air collusion.
● Construction of sealant
The construction thickness shall be greater than 3.5mm, the construction width shall not be less than twice the construction thickness, and the bottom of the deep sealing notch shall be filled with polyethylene foam material; The sealant shall be bonded on two opposite sides in the joint, and shall not be bonded on three sides.
● Acceptance of concealed works in curtain wall installation and construction
Cooperate with the owner for acceptance of concealed works, such as installation of connecting nodes between components and main structure; Installation of gap joints between the curtain wall and main structure; Installation of expansion joints, settlement joints, anti-vibration joints, and wall corner nodes of curtain wall, as well as installation of lightning protection and grounding nodes of the curtain wall.
● Technical assurance measures for curtain wall fire protection
The fire protection design of the project is guided by gbj16 and gb50045 with a large safety factor. The main fire prevention technical measures are:
1. According to the overall design and requirements of building fire compartment, set up fire isolation belt related to curtain wall with fire-proof materials (fire rock wool, fireboard, fire glue, etc.). Try to avoid a large piece of glass crossing the upper and lower fire compartments of the floor. If the beam is far from the floor structure elevation due to the appearance division, 1.5mm thick fire-resistant galvanized steel plate and fire rock wool shall be used to connect with the beam to form a fire compartment;
2. The interlayer fire protection is set at the upper and lower edges of the building structure, and the fire partition is made of 100mm thick fireproof rock wool and a 1.5mm thick galvanized iron plate. The fireproof rock wool is installed on the galvanized steel plate, and the galvanized steel plate is fixed on the transverse profile and structural edge. It can safely and reliably prevent the interlayer diffusion of fireworks. The filling material of the fire line shall be non-combustible material;
3. The fire zones on the same floor shall be treated at intervals, the responsible party shall be defined, and the non-combustible materials shall be used to separate the two zones;
4. Materials meeting the requirements of fire protection specifications shall be used to control the processing quality. The gap at the edge of the Board shall be less than 3mm, and the fireproof rock wool shall be filled tightly without gap;
5. The anchor joints of all supporting curtain walls are protected with 2-hour refractory materials. Specifically, the closed box with a height of 100mm is made of 1.5mm thick galvanized steel plate, filled with fireproof rock wool, buckled on the transfer system as a whole, fastened and sealed with the floor structure;
6. Appropriate fasteners shall be selected around the supporting plate according to the different materials of the connected parts, and the spacing between the two fixed points shall be 350 ~ 450mm;
7. Ensure that the selected materials meet the fire prevention requirements specified by the state, and materials that are flammable or produce toxic gas in case of fire shall not be used.
8. Technical suggestions for curtain wall fire protection:
(1) Each floor is equipped with automatic fire alarm equipment and an automatic fire extinguishing system;
(2) Smoke exhaust measures shall be set within a certain height;
● Technical assurance measures for seepage prevention and drainage of curtain wall
1. Conditions and solutions for leakage of curtain wall:
2. The following three conditions are indispensable for the leakage of curtain wall: water; Pressure difference; Leakage path.
3. Among them, water can not be eliminated. Only by trying to eliminate the remaining two factors can we prevent water leakage. The frame system of the project uses the sealant strip on the outside and the sealant strip on the inside to form a double seal to solve the phenomenon of water seepage.
4. Measures for discharging a small amount of leakage water:
5. No matter how perfect the curtain wall system is, it is impossible to eliminate a small amount of water seepage caused by human construction factors. The curtain wall system must take necessary drainage measures:
(1) Use caulking tape to block a large amount of rainwater on the outer surface of the sky curtain to prevent water from entering.
(2) If a small amount of rainwater and condensation water enters the profile cavity of the curtain wall, the water will be led from the outside through the method of “collecting tank, guiding tank and external drainage hole”, which can be seen in our scheme.
Well, this article is written here. If you have more good solutions to construction difficulties, you are welcome to email me at sales@sntstone.com.
