FLOWSEAL Weather Tight Expansion Foam

FLOWSEAL is a weather tight expansion foam used to provide a weather tight seal to expansion & structural joints and can be used in both new and existing applications. Depending on the degree of compression, it may also be used to provide thermal, acoustic, dust and air protection.



Flowseal is an open cell weather tight expansion foam (Polyurethane foam), impregnated with chemically stabilised acrylic and backed with a self adhesive scrim tape. It remains permanently elastic and once unpacked and applied will expand to fill the joint, including any irregularities or imperfections. Flowseal has excellent resistance to UV, mildew, ageing and will not crack, split, bleed or dry throughout continuous movement cycles.


Flowseal’s advanced technical specification makes it the preferred component for many applications in the building and construction industries, including joints between precast units , seals around doors and window frames, or between corrugated roofing panels, roof structures and roof lights ventilation and air conditioning ductwork. The exceptional flexibility and elasticity of Flowseal makes it an ideal sealant for most unevenly surfaced components and is suitable for use with brickwork, concrete, plastics, steel, timber and fibrous materials. The product provides an ideal seal where potential structural movement due to settlement or vibration for example may take place.

Flowseal is ideally suited for use as a primary or secondary seal in vertical and horizontal joints of building facades (concrete, brick, stone, insulation panels) as well as metal painted cladding systems, window perimeter curtain walling and skylights. Flowseal can be used with any water based Acrylic or Latex paint and being non-migratory is compatible with most caulking materials.

Because of the permanently flexible seal it is also widely used in the automotive industry to absorb vibration between body shell and dashboard assemblies.

Correct Thickness and Compressions

Flowseal is supplied on rolls compressed to one sixth of its original thickness and supplied with a self adhesive coating to one side. At its maximum expansion it will provide a light air baffle, however when limited to 25% expansion of its compressed thickness, Flowseal can provide a weather tight seal against wind and driving rain. Various other situations can be provided for as shown below.


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