Rotten Wood Window Repair

Our Swedish distributer, Bengt of Lignu, repairs this badly rotten wood window in this tutorial.

Preventative maintenance would have kept this window in much better shape over the years.

It’s truly falling apart, the putty has failed, the joints are open and pieces are literally dropping off.

Surely this can’t be repaired?

The wood window has rotted from the joints, which is normal. Any joint failure lets water in, and traps it there.

The rot has consumed significant amounts of the wood window.

Our rotten wood window repair starts with a complete dismantling of the window as the rot is so bad in this case.

After dismantling the window Bengt set about removing the paint from the pieces. He removed the paint using MEK (Methyl Ethyl Ketone), heat and mechanical means (sanding and scraping).

Then any wood that is so rotten that the rot can be removed with fingertips has that rot removed.

Smiths Clear Penetrating Epoxy Sealer, CPES, is painted onto the cleaned wood window pieces. This is the next stage in our wood window repair, and it toughens the timber, penetrating deeply to find all of the rot in the wood.

Next Bengt applied CPES (Lignu) twice to his window pieces. He applied as much CPES as the timber woul take on both occasions.

The Clear Penetrating Epoxy Sealer has visible penetrated the timber pieces, changing the colour and bringing out the grain.

Bengt then applied Fill-It epoxy filler to the rotten wood to restore profiles and damaged joint areas.

Fill-It does not sag (flow). This allowed Bengt to work on multiple surfaces of the same piece simultaneously.

Bengt applied filler in multiple applications. He sanded the filler between applications and achieved a structurally sound window, repaired with no rot damage remaining.

Bengt painted and refitted the wooden window.

It is a repair that will last a lifetime, on a window so rotten most would beieve it was not possible to repair.