Best support option to protect against high humidity?

[Mary Jane Ansell]

Hi

I have a portrait commission destined for a family currently living in Burma (Myanmar). The high humidity there is causing my client and I concern regarding potential damage (warping particularly comes to mind) to the support. They will also be bringing the painting back to a country with lower humidity in a few years time so it needs to stand up to this change.

Has anyone any experience/advice in this instance? Especially regarding the best way to construct a support (I often use canvas or linen stretched onto a 5mm piece of marine ply - would bracing this across the back be sufficient?)

The painting will be relatively small - only approx 20 x 20 inches, and as I say oil on canvas or linen.

Thanks in advance.

Mary Jane