Many older homes have wooden windows and many will have suffered slight weather warping over the years. If this occurs, they could end up fitting very badly into their original housing. Sash windows are especially susceptible to warping and they can stick if they are misshapen. There could also be other reasons why your wooden window sticks.
1 - Preparation
Remove the window from its housing. Keep in mind that if you are working with sash windows, they come in two halves and will have a sash chain that has weights inside the trim area. These will need to be detached from the window before you can release them. Remove any draft excluding tape attached to the window or around the frame.
2 – Check the Health of the Window
Older wooden windows are liable to warp and this could be the cause of the sticking. If they are not warped, it could be that they have multiple layers of paint that can be removed to prevent further sticking. Once you have removed your windows, check with a square edge that the corners of each window are still square. Line the edges up and see if they are still flush with each other. If there are bowed areas in the window, use a plane to remove a thin layer of the wood.
3 – Removing the Paint
Scrape off any excess paint and use sandpaper or paint remover to take the rest of the paint from the window. You will need to remove most of the paint in order to see the condition of the wood. Once you have removed the paint, check the condition of the wood and use filler to make any damage are as good. Be aware that if the damage is too extreme, you may require a complete replacement.
4 – The Window Frame
While your window may be sticking, do not neglect the possibility that it could also be caused by the frame itself. Run a thorough check of the frame and give it a good sanding to make sure that all the areas where it meets the window are free of debris or damage. Sand thoroughly and wipe with a tack rag.
5 – Repainting
Mask the glass panes so that you do not get paint on the glass. Once the filler has dried completely, sand it with fine-grade sandpaper and wipe with a tack rag. Apply a coat of primer to the window. Allow to dry thoroughly and then apply the first coat of paint. Once the first coat is dry, apply the second coat.
6 – Refitting the Window
Now that you have completed repairs to your window, you can replace it in its housing. If you have sash windows, reattach the sash chain and hang the bottom sash first. Next, add the top sash and test your window by opening and closing it a few times. You should have a smooth movement in the window frame and no signs of sticking. If you need to replace your draft excluder tape, do so carefully so that it doesn’t twist during application.