Seal-it® 471 PU-FOAM FLEX

Seal-it® 471 PU-FOAM FLEX is a highly flexible, airtight and highly insulating 1k insulation and installation foam, specially designed for flexible and airtight sealing and filling of joints, adjustment and installation spaces, seams and connections between various building components, and that moisture-cures into a durable foam that retains its flexibility.


  • Specially developed as a flexible insulation and installation foam, with a high thermal insulation value, to apply a fully vapour-tight and airtight seal for air leaks between building components in building and home structures.
  • Flexible and airtight sealing of expansion joints, connections, seams, cracks and holes, such as between/along interior and exterior façades, cavity walls, partitions and ceiling, roof and floor components.
  • Seal and fill adjustment and installation spaces between, along and around structural and façade components, such as prefab wooden and concrete parts, aluminium, steel, wood and plastic sections and door and window frames.
  • Sealing and filling of penetrations in interior and exterior walls and in façades, floors and roofs.
  • Adhere and seal insulation panels/boards and panel materials together in the construction of façades, floors, roofs and interior and exterior walls.
  • Seal connections in ridges, dormers, chimneys, air exhaust ducts and bay windows.
  • Fill, seal and insulate hollow spaces/holes in roofs, floors, façades, ceilings and interior and exterior walls.


  • Flexible quality, excellent movement absorption.
  • Fully vapour-tight and airtight, 100% sealing of air leaks, stops unnecessary energy loss.
  • High thermal and acoustic insulation values, achieves savings, reduces heat loss and noise transfer.
  • Excellent adhesion to stone, stucco, plasterwork, masonry, concrete, gypsum, metal, wood and many plastics, such as Styropor, hard PU foam, polyester, hard PVC and composite.
  • High output, approx. 45 litres at free expansion.
  • Versatile: insulates, fills, seals, adheres and installs.
  • Very low emission: certified VOC emission class A+.
  • Fast-curing, fine-celled, easy to work with and cuttable polyurethane foam.
  • Foams during the curing process, high filling capacity.
  • Lasting resistance to weather, water, moisture and ageing; does not rot.
  • Excellent resistance to hot and cold, water and many chemicals.

Application conditions

  • Application temperature (ambient and surface) between +5°C and +40°C.
  • On compatible, stable, clean, uncontaminated and grease-free surfaces.
  • Use a suitable brush to remove any loose particles from the surface.
  • Degrease the surface properly using Seal-it® 510 CLEANER.
  • Give the canister approx. 20 good shakes before use.
  • If necessary, use a plant sprayer to lightly moisten the surface in advance.
  • Cut off fully cured excess Seal-it® 471 PU-FOAM FLEX with a knife and/or trowel.
  • Before use, grease the threading of the gun adapter with Vaseline, PTFE and/or silicone spray, to prevent the canister sticking to the PU gun.
  • After securing the canister in the gun, the spray speed and output volume are adjustable using the setscrew on the back of the gun for efficient/economic use.
  • When not in use, tighten the setscrew on the back of the PU gun until it is closed so the PU gun can no longer be activated.
  • Always leave the canister in the PU gun until it is completely empty.
  • Remove the empty canister by holding in the trigger while unscrewing it in order to expel any remaining propellent gas.
  • Next, reload the PU gun with a full canister and/or clean the PU gun thoroughly using Seal-it® 450 PUR CLEANER.
  • If the PU gun is not working properly, put Seal-it® 450 PUR CLEANER on the PU gun. Spray through several times and let set well for approx. 15 min. Spray through again and then remove the Seal-it® 450 PUR CLEANER canister.

Standard product line


12 x 750ml canister



SI-XXX-XXXX-XXX = Article number.
Other colours and/or packaging on request.


  • VOC emission class A+

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