Is there a way to prevent people from throwing stuff down a rooftop sewer vent?

September 17, 2007 2:14 PM

Is there some sort of cap that can be put on a rooftop sewer vent to prevent to people from throwing stuff down it? My roommates and I recently endured a prolonged plumbing disaster (other people's sewage bubbling up in our toilets and tubs, flooded hallways, bailing out tubs and toilets with garbage cans at 3 a.m., etc.) and we are eager to avert a future crisis. The plumbers finally discovered large pieces of wood in our pipe, which we can only assume were thrown down from the roof, since they seem impossible to flush. There is easy access to the roof of our four-story building, and we're not interested in having some drunken putz foul up our plumbing again.
posted by zembla3 to Home & Garden (9 answers total)

This supplier may serve? The cap must still allow it to vent though.
posted by A189Nut at 2:20 PM on September 17, 2007

A cap would work, but I probably would just use chickenwire. I used to have problems with birds and squirrels getting into my chimney flue that had a cap on it. Screwed some chickenwire securely onto it and voila, no more problems. And it only cost a few dollars.
posted by wile e at 2:23 PM on September 17, 2007

You might just email this guy. I'm quite certain he knows the answer.
posted by ikkyu2 at 2:28 PM on September 17, 2007 [9 favorites]

Something like a chimney cap would do the trick.
posted by jjg at 2:36 PM on September 17, 2007

I suspect your best bet is twofold: first, a chickenwire cap or similar to keep out nature's best, and second, extend the pipe so that it's at least eight feet tall (and reinforced in some fashion) so that it can't be reached without a ladder -- that'll put off all but the most determined folks, I should think.
posted by davejay at 2:45 PM on September 17, 2007

If davejay's answer isn't enough (and it should be, unless the vandals in your area are exceptionally dedicated) wrap the top of the (tall) pipe in razor wire and/or paint it with this.
posted by Crosius at 3:34 PM on September 17, 2007

Basically you need something that will cover the top of the pipe, but let air in and out and not be easily removable by a drunk putz.

I'd drill a hole through the pipe and through something bigger, like a metal can, so that when you put a bolt through the whole deal there is about an inch of clearance all the way around the pipe and about an inch and a half of clearance between the top of the pipe and the bottom of the can. Bolt it all together and then mash the last few threads of the bolt just enough that you can't get it off without some serious effort.
posted by Kid Charlemagne at 3:50 PM on September 17, 2007

You have to wonder if whoever did it had heard some version of ikkyu2's story and wanted to check it out for themselves.

The sound effect the site adduces seems fairly realistic:

The board dropped.

dink denk
dink denk
dink denk

CHONNNNNNNNNNNGGGGGGGGGGGGGGGGGG.

the 'denk denk' would be the sound when the two by four glances off the sides of the pipe; it's a double sound because when the leading edge of the board hits the pipe the board rotates quickly and the trailing edge hits too; the 'CHONNN...NG' would happen when the board finally wedges itself into the resonant pipe far down its length where the pipe changes direction. At that point, the lower end of the board would be fixed violently into the pipe, and the upper end would be more or less free to vibrate madly against the side of the pipe the way kids used to make plucked teeth of a comb vibrate against notepaper.
posted by jamjam at 5:01 PM on September 17, 2007

All you need is a U Bend or a pair of street elbows (or a street elbow and a regular 90). They'll give you a 180 on the top of your stack and people won't be able to drop things in. Anything they can stuff in that'll fall into the pipe should be able to continue all the way to the main sewer. Plastic fittings just glue onto plastic pipe. If you have a lead or cast stack you'll need to get a clamp on fitting and for copper you can go clamp on or soldered fitting.
posted by Mitheral at 8:02 PM on September 17, 2007