Downdraft!

Ron Howard hasn't made a movie yet that dares to explore a condition as threatening as Downdraft! Downdraft! is the unfortunate occurrence that occasionally happens with a composting toilet where the breeze blows down from the top of the vent stack, wafting across the lovely forested outdoor area with the needling scent of urine.

The jokers that make these toilets can't keep their documentation straight and range from telling you to be sure to get your vent pipe as high as the highest point on the roof to suggesting that it be 8 feet higher than that point. If you take a gander at the photo above, you'll see how our stack rises up past a relatively low point of the sloped roof, making the 8-foot extension I added to the original stack, ridiculously tall. All of that is bound to the edge of the roof with a couple of brackets, but should a strong wind get blowing, I fear it will snap, taking some as yet undetermined amount of roof with it. If you dig deeper in the assorted literature, you might find mention of using guidewires to support the vent piping, though I'm not sure how to effectively attach that to the pipe and surrounding trees.

Thankfully, the pipe itself is thin PVC and quite light, though that doesn't make it easy to find. The wizards at the toilet company figured they would use piping designed for central vacuum systems, the kind you might have heard about from the 50s, where the lady of the house (or the maid) can plug into the central system from any room with just a vacuum hose attachment. These pipes usually come in 8-foot lengths and ship for a load of money. Or you can call all over the region to track down a place that still stocks this stuff, which is what we did.

While they're at it, the toilet people charge a premium for their composting material, a simple mix of wood shavings and peat moss, again costly to ship and hard to find. But if you call around to wood mills, you might find them willing to give you all the planar shavings you can haul away for free, the buy the peat moss separately and mix. For about 6 bucks, you can have as much material as would cost you 50 bucks from the toilet people, thus avoiding throwing your money into the barrel (the new "flushing your money down the drain").