Sealing interpanel joints

This is the joint where the sealant is located outside, in the open joint, the sealant is inside the joint. The aging rate of all sealants used depends on the strength of exposure to ultraviolet radiation, the intensity of precipitation, "acid rain", the tightness of an open joint depends to a very large extent on the quality of installation of joined structures (panels). Joints of large-panel buildings that are insulated with expandable polyurethane compositions, joints of large-block buildings are of the closed type. Open joints are joints where the sealing is provided with special structural elements, such as water screens and aprons, as well as with the help of an anti-rain tooth and a crest, the so-called labyrinth configuration of the mating edges of the panels. Air insulation is achieved by gaskets and insulation materials. Windscreens are made in the form of tapes made of polyolefins or metal, installed in grooves up to 20 mm deep. A sealed joint area is part of a sealed joint with a gap in which a sealing material is placed that protects the joint and the room from moisture and air. Joints of a drained type are joints where insulation and sealing are provided by a special sealing gasket and mastic reinforced at the mouth of the joint, or by a self-adhesive tape. Also, the sealing of joints is enhanced by structural elements for removing water - decompression cavity, special drainage aprons, drainage holes.

This is a cavity of a sealed joint that provides a decrease in the air and moisture flow rate, equalizing the pressure of the outside atmospheric air, and reducing the kinetic energy of moisture drops. Sewer devices for draining water from a decompression channel are made in the form of aprons and tubes, from materials resistant to atmospheric effects. During new construction, sealing of open joints is not performed, but it is used in the repair of such joints.

Between window and door blocks with quarters of panel walls is made around the perimeter of the blocks with special sealing mastic. This also applies to sealing panel joints in low-rise construction.

Sealing joints in the form of gluing seams is characterized by high maintainability and lower costs for sealing materials. Typically, the flow rate of the sealant in the coating joint is three times more, joints than glued.

Self-adhesive sealant has exceptional adaptability. Sealing joints with such a sealant is very simple to perform, the technology of work is greatly simplified, and this at a fairly low cost. The term "self-adhesive sealant" comes from the expression - "self-adhesive", "self-adhesive". When sealing panel joints with this material, the compatibility (in chemical composition) of the sealing building materials should be taken into account. Self-adhesive sealants adhere (adhere) to almost all building materials and to most other sealing materials.

When selectively sealing panel joints, you must be guided by the following rules:

• When leaking joints of the end wall panels, it is necessary to seal the joints of the entire end facade of the house and the joints between the end panel and the longitudinal wall.
• When the vertical joint of the longitudinal facade is flowing, it is necessary to seal all vertical joints along the entire height of the house, as well as all the sealing of horizontal joints adjacent to it.
• If the horizontal joint is defective, all joints of three to four vertical rows of panels are subject to sealing.
• When sealing panel joints, it must be remembered that sealants at the junction of panels and other structures are subjected to tension and compression from temperature fluctuations, from shrinkage and "creep" of concrete, to the stresses that arise when the entire house is upset. Moreover, the greater the ratio of the thickness of the sealant layer to the width of the interpanel seam, the stronger these loads. Therefore, the sealant layer should be half as much as the seam. It is very important! First of all, when sealing panel joints with a mouth greater than 10 mm. And this, unfortunately, is the majority of prefabricated panel buildings in Russia.

Reasons for poor joint sealing

• Design and Runtime Errors
• The combination of hard seals with elastic. Hard seals (mortar of a mixture of cement and sand) are destroyed and wedged into elastic mastics. The sealant will retain its elasticity longer if applied to soft pads, and the cohesive strength of these pads should be lower than the strength of the sealant.
• Self-adhesive tape sealants can not be glued "pull", it is necessary to glue with a sag. Temperature fluctuations inevitably lead to panel movements, and the sealant will simply tear or peel.
• Self-adhesive tapes must be glued with an adhesive lower underlayer, good sealing of panel joints, this means a voltage close to zero inside the sealing material.

The main materials used for sealing panel joints are mastics and self-adhesive tapes. The brands of these sealants are different, and have a different scope, they differ from each other and elements. The main accompanying material, which is necessary for sealing joints, is a sealant that performs the function of thermal protection and the base for mastic and self-adhesive tape to be laid. The best sealants are foaming polyurethane (PUF) formulations. For drains, polyolefins, stabilized polyethylene, and thin galvanized steel (0.6 mm) are used. The joints made of polyolefin are welded with a stream of hot air, the joints of the metal with folds, which are then sealed with a self-adhesive cord. The joined panels can be with an anti-rain tooth (crest), otherwise a so-called flat horizontal seam is obtained.

Areas of application for self-adhesive tapes

• Under the window drain, around the perimeter from the outside (must be protected from UV)
• Sealing joints of lanterns, translucent structures of winter gardens, repair
• Sealing metal roofs and places where roofs adjoin walls
• Joint sealing for improved sound insulation
• Sealing joints from the inside to increase heat resistance and fire resistance
• Sealing joints between window frames and door frames to the walls of buildings for any decoration of slopes
• For priming surfaces before applying sealant

Work on sealing joints of the outer walls of prefabricated prefabricated buildings during new construction should be standardized by SNiP 3.03.01-87 ("Bearing and enclosing structures"). The rules are spelled out in the "Installation of precast concrete structures" section. Joint sealing consists of a set of measures, including a joint insulation device, installation of gaskets at the mouth and application of a special sealing mastic or self-adhesive tape. Panel repair work to eliminate defects in their production and new mechanical damage is usually carried out in the workshops of homebuilding enterprises. Work on sealing joints with the use of special airtight tapes should be carried out on a floor-by-floor basis, and always before the installation of internal walls. The surface of the joints before the tape sticker must be degreased and cleaned of dust. The tapes are overlapped (100-120 mm). This end of the lower tape goes over the tape from the junction of the mounted floor. The joints of self-adhesive tapes are located at a distance of 300 mm from the intersection of the joints of the panels of the structure. The use of rolled and bituminous materials (roofing material) for pasting air insulation is unacceptable! During work on sealing closed joints, gaskets are installed at the mouths of the joints. Installation of gaskets and subsequent work on applying sealing mastic is carried out from suspended cradles, from mounted scaffoldings and lifting towers, from scaffolds or any means depending on the height of the building’s floors, in accordance with the safety instructions and operation of these tools. It is also advisable to build a special insulator booth for sheltering and heating workers and for temporary storage of equipment and other devices with tools, for storing mastic supplies, overalls, solvents, gaskets, air strips, first-aid kits, etc. Before starting work on sealing joints, use the ability to inspect the joints for a final clarification of the state of the joined elements. Damaged faces of these elements can be repaired with a polymer-cement mortar.

When sealing joints, the surfaces must be cleaned and degreased before applying the mastic, previously dedusted and freed from the influx of excess solution and dirt by pneumatic and electric brushes, and rags, using white spirit solvents, blowing with compressed air, and drying using special apparatus for drying. Install the gasket after installing the floor panels. These gaskets should be crimped 20 to 50% of the diameter, work usually requires gaskets of various diameters, given the possibility of variation in the size of the joints, which are unavoidable when installing prefabricated elements. If the width of the mouth is less than 12 mm, it is possible to seal them with cheaper materials, such as tow. Sealing gaskets when sealing the joints are laid in a solid line, tears are not allowed. A rounded wooden spatula is used, the gasket is started without tension, connecting along the length using adhesive polyethylene or cloth insulation tape. The joints should be at least 300 mm from the intersections of the vertical and longitudinal joints of the building panels.

Absolutely unacceptable:

• Nail pads to panel edges
• Install the panel with gaskets already fixed on them, unless specifically specified in the project
• Use two or more pads twisted together
• Lay gaskets at the mouth without prior cleaning
• Apply sealing mastic and self-adhesive tape during rains and snowfalls (if rainfall on the surface is real).

Apply mastic to the sealed joints using hand and pneumatic syringes of various grades, pumping at the mouth and moving the tip along the sealed, while pulling the trigger of the syringe evenly and without gaps, inflows, or voids. When injecting the mastic into a horizontal joint, the angle between the longitudinal axis of the syringe and the joint is about 45-60 °. After applying the mastic, it is leveled with steel or wooden lining, with soapy water, in winter, with salt water. The thickness of the mastic layer is determined by the project. Polyurethane foam mixtures and self-adhesive tapes are applied at a temperature not lower than minus 10 ° C.

Repair work on sealing joints significantly exceeds the volume of sealing in new construction. All or almost all technological operations are carried out using scaffolding or industrial climbers ( industrial climbing ). At the same time, the use of mastics and sealants is most effective. Repair work of sealing joints, which are the elimination of defects in the seams of panel buildings during the warranty period of operation, is the responsibility of the homebuilding company. After the warranty period, the joints are sealed by specialized organizations.

The decision on the need for repair sealing joints is made in case of complaints of the population after a field examination in the autumn-winter period. This time gives a full identification of defects in joints - leaks, freezing, etc. Inspection of buildings is carried out from the outside and from the inside. Inside, apartments with defective joints and all adjacent apartments (nearby, above and below) must be examined. The apartment measures relative humidity and temperature, a survey of residents is conducted in order to obtain and clarify information about all problems and isolation. In the case when the cause of the defects remains unclear, additional studies are carried out using special methods, for example, using thermal imaging equipment. The presence of individual defects in the tightness of joints is less than 30% of the rooms of the building facing the surveyed facade; these joints and their adjacent ones are repaired, as well as joints at the junction of window and door blocks are repaired. Successfully get rid of the freezing of the outer enclosing panels allows the technology "Warm seam" . In the case of point freezing and air permeability, repair to seal joints takes place only in defective areas. In buildings with open joints, all joints should be repaired as closed. Joint defects in more than 30% of the premises are the basis for repair and sealing of joints of the entire considered facade or end of the building. Sealing the outer joints of the building panels is carried out only in dry weather and preferably at positive air temperatures. Before work on sealing joints, it is necessary to mount handling equipment, conduct electricity, prepare tools and boxes for storing them, be sure to install warning posters in the work area, instruct workers on the safety and health rules.

• SNiP 3.03.01-87 Supporting and enclosing structures
• TP 196-08 Technical recommendations on the technology of sealing and sealing joints of external wall panels
• TR 95.07-99 Technological regulations for the construction and installation works in the construction of buildings and structures. Paragraph 07. Sealing joints of external building envelopes
• 44-03 TC Technological map. Sealing joints of external building envelopes
• Technical instructions for sealing joints