Paint or Stain?

RWC siding? Please define your terms rather than using regional abbreviations.

I've been using site-applied (all sides) solid color latex stains on wooden siding (from KD planed spruce to rough-sawn hemlock). Two coats offers almost as much color and opacity as paint, is a good deal more durable and long-lasting than semi-transparent stains, but never requires scraping like paint in order to refinish.

Stain will rarely have the longevity of paint because it has less resin/binder, but the UV resistance of a finish is directly proportional to the amount of pigment (just like with human skin). However, a good stain job will outlast a poor paint job because it will not blister, crack, craze or peel. And it just slowly fades until aesthetics requires a recoating.

Robert - Thanks for the input.

RWC = Red Western Cedar, FC = Fiber Cement

WRC = western red cedar

hey robert and all:

what are your thoughts on NO stain or paint on roughsawn hemlock siding? we're looking for a rustic, raw wood look... but how much will durability suffer? the assembly would be installed rainscreen style, so allow drying/moisture drainage... thanks.

Forrest,

Wood is a living thing, and ages quickly if exposed to the elements without protection. Even that wonderful Cape Cod cedar shingle gray is merely wood that looks like an elderly farmer's face: cracked and wrinkled and marked by the ravages of time.

And it's a self-stoking cycle. UV breaks down the cell walls of the wood while the swelling and shrinking from moisture cycles warps and cracks the wood, dirt and dust and smoke and pollen collect in the broken cellular structure, these organic materials absorb moisture and contribute to freeze-thaw damage, which further opens the surface and accelerates the deterioration.

On an unconditioned barn, this may not matter very much. But on a house, it does, and siding can be expensive to replace. This is why I always recommend an opaque stain, no exterior siding wider than 6" (more likely to split and warp), and horizontal lapped rather than vertical orientation for better drainage (though with a rainscreen that makes less difference).

And, by the way, I've never built a rainscreen. I find it unnecessary except in the most severe rain and wind zones, wasteful of materials, problematic to integrate with flashings and WRB, and can create a space for insects to nest or fire to travel.

Forrest:
I have to agree with Robert 100%. Trees have bark for a reason, our use of protective coatings is to emulate that protective skin.

I personally don't have a lot of field experience with stain vs. paints but I've been looking into alot recently as I am residing my own home. For the most part I am following Robert's advice and using a solid color stain (but with a drainspace). According to my research w/ product literature and speaking to manufacturing tech people each siding choice has properties to be aware of. With Western Red Cedar its tannin bleed so make sure the products you use account for this. On some of my D&Btr Red Cedar siding I will be sealing the knots with shellac and on other part I will omit this extra step. (I can get back to you in ten years w/ the results : ) ) Fiber Cement is more dimensionally stable but its issue is PH, although I know less how to take precautions with this.

I imagine if you use a factory applied finish you still need matching product to paint your cut ends and clean up dirt marks that are bound to happen in installation.

Unpainted siding is possible with the right design in the right conditions. I've seen two examples of 1" thick poplar board and batten siding that has aged beautifully for over two decades. These were both designed by an architect who understood how to manage rainwater. Both buildings are in the woods in Central Minnesota and are protected from full sun (except in the winter) so experience mild UV degradation.

I've also seen in books wood siding torched to a charred black finish with interesting affect. This is purportedly a technique in traditional Japanese building.

I once lived in the woods of Maine with a chainsaw-wielding nun who was raised on a farm and finished the buildings with used motor oil. Perhaps better recycling than disposing of it, but I don't expect the drips were much good for the surrounding soil.

Speaking of Rainscreen / Water Penetration issues you may want to review these You Tube video animation on Rainscreen Stucco:
http://www.youtube.com/watch?v=lgCbk76f3-E

Manufactured Stone Veneer:
http://www.youtube.com/watch?v=O3TTRmk-2Uo