Lacrysil "EXTERIOR JOINT A" Acrylic Sealant is specially designed for sealing external installation joints of windows, doors, balcony units, and facade structures. It creates a vapor-permeable, 100% waterproof, weather-resistant, and UV-resistant joint that prevents condensation and provides long-term protection against precipitation, wind, and temperature fluctuations. This is the external (vapor-permeable) version of the sealant for installation joints (as opposed to "B" — the internal vapor barrier version).

Recommended Applications:

• External installation joints of window and door frames

• Sealing joints between the frame and the wall/opening (from the outside)

• Sealing balcony units, shop windows, facade elements

• Filling joints around polyurethane foam (external layer)

• Sealing connections between frames and facade materials (brick, aerated block, concrete, plaster)

• Exterior work on facades, terraces, roof abutments

• Sealing openings around external pipes, ventilation, cables

• Protecting polyurethane foam from direct sun, rain, frost, and UV radiation

Suitable for these surfaces:

• PVC, aluminum, and wooden window/door frames

• Concrete, brick, aerated block, foam concrete

• Cement and gypsum plasters

• Metal (aluminum, steel, galvanized)

• Old tiles, porcelain stoneware (external walls)

• Other mineral and porous substrates (after priming)

Not Recommended For:

• Internal installation joints (use the "B" vapor barrier version for interiors)

• Joints with constant water immersion or high water pressure (swimming pools, foundations — use MS polymer or special waterproofing coatings)

• Aquariums or potable water tanks

• Surfaces constantly submerged in water

• Joints subject to heavy mechanical loads or constant friction

Important Recommendations Before Application:

• Surfaces must be clean, dry or slightly damp (can be applied on moistened substrates), free of dust, grease, old foam, and detergents

• It is recommended to degrease metal and plastic with alcohol or acetone

• For better adhesion on porous surfaces (concrete, brick, aerated block) — pre-prime with a deep-penetration acrylic primer

• Apply after filling the joint with polyurethane foam (external layer over the foam)

• Do not apply during heavy rain or high humidity (dry weather is preferable)

• For vertical joints — high thixotropy, no sagging

Typical Usage Examples:

• Sealing the external joint between a window frame and the facade (protection against rain and wind)

• Sealing joints around door frames outdoors

• Filling gaps around balcony units and shop windows

• Protecting polyurethane foam from UV and precipitation on facades

• Sealing connections between frames and brick/aerated block/plaster

• Sealing openings around external pipes and ventilation

After full curing (24–72 hours depending on layer thickness, temperature, and humidity), the joint becomes resistant to weather conditions and requires no additional protection. The joint can be painted with acrylic facade paints.

Lacrysil "EXTERIOR JOINT A" Sealant — professional external protection for joints. Vapor-permeable, waterproof, withstands sun and frost — for the long term!