Installation of windows and doors with polyurethane foam

June 2020 – Window and doorframes are made of materials such as wood, aluminium, steel and plastic. The use of polyurethane foam in filling the gaps and for the installation of windows / doors can significantly reduce the cost of work and increase its insulation capacity. It is important that before installation, you know the properties of polyurethane foam to avoid damage and costs in the process.

What do we need to pay attention to before installing frames with polyurethane foam

As the polyurethane foam expands during curing, it is important to know that forces are at stake in this process. However, if the frames are not properly stabilized with mechanical attachments (e.g. spacers, bolts or levers), deformation can occur during the process of foam curing on PVC, aluminium or wood frames. When installing the frames always use spacers / bolts between the frame and the wall to ensure that the frames are placed at the 90 ° angle and remain stable (they hold their initial position). Well-installed spacers / bolts between the wall and the frame will prevent any deformations that can occur during the curing. We recommend placing the spacers / bolts in spacing of 50 cm.

Remove spacers / bolts for installing the frames only when the foam completely cures. We recommend that the joints around the frame are as small as possible, and not wider than 2.5 cm. The foam in the width and the depth of the joint will not expand further in one to two hours after application at normal room temperature and humidity.

The curing of polyurethane foam is influenced by many factors: temperature, room humidity, type of substrate and the width and depth of the joint. As the conditions can be very different from installation to installation, it is difficult to determine when the expansion / curing of the foam is completed. When in doubt, keep the spacers in a little longer. We recommend keeping them in at least 24 hours.


We use one-component polyurethane foams Neostik for sealing, installation, insulating, filling and gluing various construction materials and objects. Foam easily flows out from the aerosol can with the spray gun or ‘straw’. Shake the can well before use. After application, the polyurethane foam in combination with the room temperature expands and cures under the influence of moisture from the substrate and the air. Neostik has in its portfolio several types of polyurethane foams, such as universal foam, mounting foam, foam for roof tiles, foam for insulation boards, foam with low expansion, etc. Foams are available in various packaging volumes, manufactured for application either with ‘straw’ (mounting PU foams), or application with gun (gun PU foam).


Neostik PUR FOAM UNIVERZAL allows numerous applications in the construction and electrical installations. You can use it also for filling pipes and other materials. The special formulation ensures good adhesion to many coatings. Made from high-quality raw materials and additives it enables optimal thermal and acoustic insulation. Quality valve allows the maximum amount of foam output. It cures by exposure to atmospheric moisture and has good adhesion to wood, concrete, bricks, metal, aluminium, stone and plastic.

The surfaces to be sealed must be clean, dust and oil free. Moisten the substrate before applying the foam. Before use, warm up the foam to the working temperature (the optimum temperature of the aerosol can is between 20 ° C and 25 ° C, maximum at 35 ° C). The working temperature must not be lower than + 5 ° C.

Before use, shake the aerosol can vigorously ca. 20 times, with the valve upside down. Remove the cap and screw on the extension with the ‘straw’. Half fill the gap only since the foam expands by 2- to 3-fold after application and forms a compact cell structure. The foam will expand after application to fill the rest. If you fill the gaps wider and deeper than 5 cm, we recommend you apply the foam in multiple layers.


To apply the foam, turn the aerosol can upside down and press the valve. By pressing the valve, you activate the foam, and start applying it at the bottom and then continue to the top. The binding time is usually 5 to 10 minutes and the foam is fully cured in 1.5 to 5 hours. The curing of fresh foam can be hastened by moistening the substrate, and by moistening of freshly applied foam.


When you finish applying the foam, clean the valve and ‘straw’ with a cleaner. Clean the uncured foam with Neostik PUR cleaner. The uncured foam residue has to be removed mechanically. Protect the cured foam against the effects of UV light.

When the foam is fully cured, cut it with a sharp knife.