Vertical-joint concrete PSB K50

Base

• The temperature of the base is +5°C..+25°C.  
• The substrate must be clean, solid, dust-free and absorbent.
• There must be no loose water, snow or ice in the concrete elements to be jointed. 
• Strong temperature fluctuations may cause water to condense on the surface of the concrete element. Excessive moisture condensation can be prevented by heating the surrounding structure. This must be taken into account especially in cold and humid conditions.    
• If necessary, the low-strength cement adhesive layer must be removed. Coarse surface produces best adhesion.
• The joint width must be sufficient (at least 15 mm) so that the sealing compound fills the joint completely.

Priming

• If necessary, the concrete substrate is moistened to a matte finish before installing the product. There must be no loose water.
• Liquid adhesion primers are not used with the product.

Mixing and application of the product

• Masonry work should not be carried out in direct sunlight, in the rain or during strong winds.
• The working temperature should be between +5°C and +25°C.
• The product is mixed into a smooth mass with a pipe or paddle mixer. When using a paddle mixer, the mixing time is 1 to 3 minutes. The amount of water in the product is correct when the vertical joint concrete does not flow in the joint.
• The amount of water must be in accordance with the instructions on the product card. Deviating from the recommended amount of water weakens the product's strength values, increases the risk of separation and affects the development of strength and reduces workability.
• The working time is roughly 1 hour from the mixing. 
• After mixing, the mass is pumped into the joint and levelled with a steel trowel. The element joint is not vibrated.  
• A joint that is open on both sides is cast by moulding the other side of the joint with a so-called stopper board. The board is removed when the vertical joint concrete has hardened slightly. Finally, the joint surface on the board side is levelled with a steel trowel.

After treatment

• Element joints are kept moist for 2 to 3 days after casting.

Coating

• The element joints are coated in a manner suitable for the purpose of use. The product can also be left uncoated. 
• The risk of cracking due to shrinkage of concrete elements can be reduced by using Fescon waterproofing systems at internal joints adjacent to dry interior spaces. Treat the interior concrete element joints with waterproofing primer. Apply the waterproofing over the joint and install the waterproofing tape over the wet waterproofing. Apply a second layer of waterproofing over the tape when the previous layer has dried. After this you can do the levelling work in the normal way. 

Other considerations

• Joint widths greater than 150 mm are assessed on a site-by-site basis with the vertical seam contractor.

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