Repainting timber which has an unknown existing paint finish

[James Harris]

Simple query: what preparation is required to repaint interior wood that has a preexisting paint finish?

The problem is that I don't know whether the existing paint is water-based or oil-based. Is there any way to tell and does it matter? Stripping off all of the old paint is not an option. The new paint has at least to some degree to go on over the existing paint.

I don't need the finish to be anything fancy. A basic job would be perfectly adequate for this. I just want the new paint to stay put and not to flake off over the years.

As a suggestion how effective would the following be regardless of the existing paint?

1. Give the wood a basic sanding to break the surface.
2. Clean with sugar soap.
3. Paint with undercoat
4. Overpaint with new water-based paint

Any recommendations welcome.

James

[stuart noble]

If 1 is thorough, I'd skip 2, and make 3 an acrylic primer/undercoat

[Rick Hughes]

My sequence would be different ...

1 Sand lightly to abrade surface and make it 'matt'

1. Wipe down with Meths on a cloth ... fully degreases and removes all dust (could just dust down with clean brush if not that worried about finish)
2. Undercoat
3. top coat

If wood is dirty - wash with sugar soap ... to remove dirt & any polish etc. I had to do that on first house I bought, the previous occupant was heavy smoker all wood work had a coating of tar ... horrible stuff. Took pictures off the wall and difference in colour was amazing. Her lungs must have been blocked solid.

[Nightjar]

On 10/04/2014 18:19, Rick Hughes wrote: ...

I gave up trying to clean the ceiling of the public bar of a former pub. In the end, after five washes with sugar soap that were still coming away brown, I put a suspended ceiling in below it.

Colin Bignell