Flex Seal

Flex Seal

Flügger Seal is a range of elastic sealants that cover the need for closure and filling of cracks, joints and corners when carrying out surface treatment.

Product Description

Extra flexible, moisture curing sealant, indoors. Low emission, odourless, neutral and free from phthalates and tin. Long curing time, does not shrink after drying. Paintable with extra strong adhesion and elasticity.
  • Extra flexible
  • Doesn’t shrink
  • Paintable


Joints between construction elements.
Joints between ceilings, walls, frames, doors, windows and plasterboard, concrete, lightweight concrete, cardboard plaster, fibreglass, wood, metal and painted substrates.
The filler should be sized so that the movement of the free sealant falls below +/- 20%.


Must be clean, dry, firm and suitable for surface treatment.


Remove loose material and paint by cleaning and sanding.
Remove dirt, grime, grease and chalking materials by cleaning with Fluren 37.
Can be used without applying primer on non-absorbent substrates.
Absorbent and porous substrates can be primed with Sealer for optimal adhesion.
Use the correct size/amount of joint filler, joint depth = ½ joint width.
Narrow cracks and joints are best treated as square joints.
Finish the treatment with a coat of aqueous paint.


Filler gun.
Cut off the tip of the filler gun.
Cut the tip at an angle to adjust to <joint width.
Easily workable, pressed into place and smoothed using a sealer squeegee or joint stick and water before the joint forms a skin.
Choose a tool based on the width of the joint.
Apply sealing tape if necessary and remove it immediately after application.
Cold/heat can affect the viscosity of the material.
Avoid condensation forming.
Cold and low atmospheric humidity extends drying time and full curing.
Always test adhesion and result before hanging.

Elastic joints, which can absorb temperature-related and moisture-related movements.
Dry matte non-abrasive surface with a nice finish.
Knots can cause discolouration.
Not suited for areas constantly subjected to moisture and water.
Cracking during painting can occur if the paint does not have the same elasticity as the sealant.
Do not paint expansion joints.

Be Aware

Joints <6 mm or >30 mm do not absorb maximum joint movement.

Technical Data

Plaster & Sealant
Density (kg/liter)
Weight %
Volume %
Min. +5°C
Max. +80°C
Dry to touch at 20°C, 60% RF (Hours)
Recoatable at 20c, 60% RF (Hours)
Fully cured at 20c, 60% RF (Days)
25-30 shore A
Cleaning of Tools etc.
Remove uncured sealant using white spirit. Remove hardened sealant mechanically.

Storage: Cool, frost free and tightly closed

Protection equipment for: Spray painting: painting suit, full face mask with combined filter. Painting: eye protection, gloves. Sanding: respiratory protection.

Environment information: Clean off the paint from tools and wash them with water. Bring remains of fluent paint to the local recycling centre. Minimize your paint waste by pre-estimating how much paint you need. Keep the leftover paint for future use so you can effectively reduce the environmental impact.


September 2020