wooden ceilings

Our new (to us house) has wooden ceilings and supports in the basement living area, two rooms have had these ceilings covered by plywood and gloss painted. We intend to remove this covering on our return in April and would like to know the best way of preserving the wood, should we oil or wax it, providing the ceilings are sound?

Hi Kath, welcome to Permies!  

Do you know if the original wood ceilings were ever exposed?  If so, they may have been coated with something years ago (wax, oil, varnish, shellac, etc) to protect them and you may not have to do anything.

Even if they've never had any sort of protection, they may not need any.  Unless it's particularly damp or humid in your basement.  A single coat of water based varnish is all I use on raw wood in our interior projects.

Thank you Mike, yes I think that the wooden ceilings where exposed initially because the third basement room the old kitchen was never covered with plywood. Upstairs the wooden floor is covered with lino which we intend to remove. Meanwhile how will we know if they've been treated in the past?

Once you remove the plywood covering, gently clean a spot on the wood ceiling and take a look, it will look like it has something on it if it does. Usually a shellac finish will age to a nice golden yellow and it will feel slick (like the paint on a car), if it is varnish it will do the same. Both of these and wax will dissolve in alcohol, and it would most likely feel tacky if it did start to dissolve.

Ditto what Redhawk said.  

Just to be devil's advocate...  Does it matter if it's been treated or not?  If it looks nice, leave it be.  Just a thought for what it's worth....

Have you considered insulating the floor, and perhaps putting a new ceiling in place to cover the insulation?

The little house we have bought is in Bulgaria, family and work commitments mean  not returning until April time.  I was asking for information about the wooden ceilings and possible treatment because we need to take the plywood off to:
make sure its not covering any "nasty's" such as woodworm.
make sure the ceilings are "sound".
we like the wooden ceilings and feel that uncovered/free from the plywood the timber will be able to "breathe".
With any luck no "treatment" other than a good clean will be needed.
We will also need to install an internal staircase because like most Bulgarian village homes the two levels have separate entrances.
Than you all for the advice so far.

That sounds somewhat similar to the ceilings in this house: Wooden floor, then a gap filled with dirt, battens below that holding it in place. Then a gap (here are the beams that hold the floor up) and another layer of battens with wire attached that holds straw that in turn holds the plastering.
The lower layer of battens, straw and plaster was removed, exposing the second layer of battens (and increasing the room height by 15cm). Unfortunately they were not exactly pretty and had gaps between them.
The gaps were filled with clay putty and the resulting surface leveled out using more clay. Finally one (at some places two) layers of white linseed oil paint were applied.

The whole process requires a lot of work and time, but the result is impressive.