Rain Screen Beetle Kill Siding

The abundance of beetle kill pine here in Colorado makes it a very affordable and sustainable building material. Most pine species are considered soft and often are riddled with knots, so while it can be used untreated for rustic furniture or trim indoors, untreated pine is not known for its durability outside. Which got me thinking…

How could I incorporate this inexpensive, readily available material into my newly framed 7,200 cubic foot man cave as a siding application?

Traditional lap siding and vertical board and bat applications set the material directly against the building paper which leads to bending, warping, cupping and cracking as the siding material is weathered unevenly. Beetle kill pine, milled down to manageable lap siding thickness, would surely fall apart over time as knots pop out and cracks develop.

What if rough sawn 1×6 beetle kill was attached to furring strips to hold the material off the wall, with gaps between the boards it would allow it to breath on all sides, right? When it rains, the whole board gets wet. When the sun is out, the whole board dries out. The obvious drawback is the additional waterproofing and flashing needed to make the surface behind the “rain screen” watertight. But with the beetle kill being so cheap, and with an abundance of free labor, I decided to give it a try. Ladies and gentlemen…may I introduce to you…The Rain Screen Experiment.

After painted cement panel siding was applied over the house wrap, the rain screen areas were flashed with metal, then 6″ adhesive flashing with the black, 30# building paper over that.

With the 3/4″ furring strips anchored securely to the frame, the rough sawn pine boards were cut to length and sealed with two coats of a stain/sealer. It should be noted that the pine was originally purchased from the mill after a spring snow storm and the material was, shall we say, damp? So we stacked the boards on stickers and allowed them to dry for several months.

And here is the finished appearance. The cement panels cost about $1/s.f. for the material, the beetle kill pine was about $0.60/s.f. but with the flashing factored in it was also about a $1/s.f. The upside of this project is that I was able to side our garage for very little money. The down side was that it took an embarrassingly long time to finish. Oh well, as I tell my clients, there are three major components that dictate the course of any project, money, time, and quality. You can only control two of them, so choose them wisely! In this case I opted for a quality finish on a tight budget, the schedule flew out the window a long time ago.

With the siding complete the experiment begins, how will this material hold up over time?