Removing construction foam

7 practical tips

Construction foam is popular because of its insulation, filling and adhesive properties. The latter could however cause problems if, despite all precautions, the PU foam lands on areas where it shouldn't. Of course, the question is now how to remove the foam again.

1. React immediately

This is easiest on construction materials as long as the construction foam has not yet dried and hardened. If you are quick enough, it may be sufficient to simply wipe the area carefully with a cloth and clean. Ensure that you do not smear the PU foam. Therefore, use several cloths, if larger areas are affected. You can mop up the fresh foam more easily without smearing any unaffected areas.

Remove hardened PU foam

How to remove the hardened construction foam without damaging the surface.

2. Cut off the coarse PU foam residues

Cut off as much of the residual material as possible first. The less construction foam on the surface, the easier it is to remove. You can use razors, carpet knives, cutters or any other sharp blades suitable for using carefully on surfaces. Please be careful and do allow the knife to slip!

3. Use PU foam removal agent

DIY stores and special retailers stock special PU foam removal agents that remove the hardened residues in a chemical process. All PU construction foam removal agents function and are applied in a very similar manner. However, some details may vary. Please read the manufacturer's instructions first. Otherwise, the following three steps generally apply:

  • Cut off as much of the residual PU foam as possible before applying the removal agent.
  • Apply the removal agent as stated on the packaging.
  • Allow the agent to work for approx. 30 minutes (read the manufacturer's instructions for the respective product)
  • Remove the softened residues with a wooden spatula. Do not use any more water here.
  • Then clean the area again.
  • Repeat the process if necessary.

4. What do you need to bear in mind when using the PU removal agent

When selecting the removal agent, ensure that it is suitable for the respective surface. To do this, read the instructions on the packaging or ask your dealer.

In general, PU foam removal agents are compatible with tiles, stone, glass, wood, aluminium and steel. Special care needs to be taken with anodised materials and varnished surfaces.

5. Important: Try the PU removal agent on a hidden place first

PU removal agents can cause unwanted discolouration of the surface. Therefore, you should always test it first on a hidden place first to check how the compatibility of the construction foam removal agent and the surface.

6. Protect skin and eyes

PU foam removal agents work on the basis of a chemical reaction Like all chemical construction products, you should always avoid contact with skin or eyes and wear protective clothing and goggles. Also, always ensure that the work area is well ventilated.

7. How to remove PU foam mechanically

You can also try to remove the PU foam residues mechanically. First, cut off as much of the larger residues as possible with a sharp knife. Then you can sand off the remaining foam carefully with a fine wire brush, if the surfaces are moderately hard (for instance, plastic windows and sills). You can use a Ceran hob scraper on very hard surfaces.

CAUTION! You should always try out any mechanical methods first on a less visible part so there are no unwelcome surprises.

How to avoid PU foam splashes

However you decide to get rid of the splashes, the best advice we can give you is to prevent the splashes from happening in the first place! Cover all sensitive surfaces and surrounding areas before you start working. You should also protect yourself by covering your skin by wearing long trousers, long sleeves and gloves. Also, always wear goggles to protect your eyes from PU foam splashes.

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