Here is what I do when I work with wood. I have built circular roofs with balsa and other crazy looking structures in my times, but each time the biggest pain for me was painting it when done... well, actually, as for a lot of things, I started to do it backwards, and guess what? IT IS MUCH EASIER :P
Ok, when I say "paint", I really mean "drench it with home made wash" (but it does not as professional).
So, first, you make youself some washes. No-one wants to use top of the range £2 or £2.50 per 17ml bottle washes designed for miniatures when a £2/1,000ml DIY deal works just as well:
I could go on about how to make it, but as "TheTerrainTutor" has done a cracking youtube tutorial, I will re-direct you to him, I would be saying the similar thing.
The ONLY Small tiny thing I would say is: Do not use dish-washing liquid, but use Dish-washer Rince aid instead (less bubbles!)
A guide to making easy terrain washes - TheTerrainTutor
A Guide to Making Pro Terrain Washes - TheTerrainTutor