Expanding foam - a natural alternative

Expanding foam is used extensively for window and door fitting. Terrible stuff. It is used to cover up poor workmanship and it also can fail quickly and leave you with poorly insulated and leaky window surrounds (note that some foam is now designed to flexible, but did you know that!?)

The trouble is, what to use as an alternative?

Well, there are alternatives out there. The choice depends on a number of factors:

The state of your reveals (the wall part next to the window)
The time that you have for the work
The finances available to you
Your sensibilities for having a job done correctly
The need for airtightness in the design of the building

The main alternatives are:
1. Expanding tapes. These are superb at creating a weathertight, airtight and insulating fit for doors and windows, especially in new builds where the reveals are relatively accurate and smooth. Companies like Iso Chemie produce excellent tapes that expand to fill the gap, whilst not attaching themselves directly to the reveal, thus the window can move and flex and not break the seals. Brilliant.

2. Cork filler. A new product from Auro combines natural latex with cork to give a paste similar to caulk that can be painted over etc. This is better for reveals that are jagged and would require a lot more remedial work before a tape could be fitted. The filler remains flexible and hence maintains a seal even when the windows flex and vibrate (as they all do).

Both systems will cost more than the cheap expanding foam, but then they do a proper job that will last. So if you don’t want leaky and draughty windows think about how they are fitted and whether you want to live with windows that perform as expected, or whether you want to waste your money on a false economy.

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