Toby

[BRIAN ROBINSON]

This is my first query, I trust it makes sense, I am renovating a house approximately 50 years young and it has a number of panel doors in the bedrooms etc, they are of a plywood finish and range from small up to 2000 mm x 500 mm all are in extremely good condition but some have developed a BOW? over the length of them resulting in a slight rounded effect when they are closed, if 2 are side by side such as a wardrobe you have a bump in the middle, these doors have been made to measure and are all quite light and around 25 mm thick, I have about 30 of them and it would be a shame to take them out and replace them, what I would like to know is there someone that can help advise me as to how to straighten them, the bows are not great but are noticeable, any help would be appreciated.

[fletty]

Hi Brian.
I'll start the responses. Timber was a living material and hence it is porous. It changes dimensions with humidity as the moisture content changes inside the timber. Uneven moisture content will usually result in the timber bowing or twisting. This is particularly so for solid timber constructions but less so for constructions made of plywood. The dimensional changes are usually across the grain and, because plywood is made of timber plies with the grains of each ply rotated 90deg, the movement in plywood is usually cancelled out.
The biggest contributors to unsymetric moisture content are environment (eg bathroom on one side and hallway on the other) or unsymetric sealing against moisture ingress (eg one side of the door painted and the other side not).
An old trick is to take a door outside and leave it under cover but with equal access of air to both sides. If it straightens then the problem was probably environmental. If it stays bowed then the problem is probably uneven sealing of the doors.
I have seen bowed doors that were allowed to get wet on one side and then painted but this is unlikely to be the problem in a 50+ year old house.
I'd start by putting the worst door outside BUT the family tends to get distressed if it's the bathroom door!
good luck, Fletty

[BRIAN ROBINSON]

Thank you for your rapid reply to my problem, I will try what you have suggested and see what happens, the bows are not great but noticeable, most people probably don't notice them but they tend to annoy me, the longer ones being the worst show up and it would be nice to tidy them up, it will also give me something to do, I will remove a couple and let you know what progress over time, also will get the hang of this Forum?
Cheers Brian