Question regarding smoke jacks

[Ray Dunakin]

When a smoke jack is used on a roof with an uneven surface, such as tiles or corrugated metal, how do they usually fit the "flange" at the base of the jack to the surface, without leaving gaps?

So far the photos I've seen don't make this very clear due to the angle of the photo, and the distance. In fact I'm looking at one right now, which shows a smoke jack on a corrugated metal roof. It looks like it's just sitting on top of the corrugations -- I can't see any attempt at preventing rain from getting under it from the "upslope" side.

[eTraxx]

Ray. When I was a youngster I lived in a house that had a tin roof (corrugated). Every so often I was sent up to the roof to fix leaks. I had a bucket of 'some kinda' black tarry-like substance. It was something made for fixing leaks .. which usually meant 'taring' around the nails that secured the corrugated metal to the wood underneath. (the 'nails' had a collar of lead that 'sorta kinda' sealed against water when hammered down). Just based on me .. on top of the roof with a bucket of tar and a stick to spread it .. I would have simply 'schmerred' the tar around the smoke jack joint. Thats' what me .. a 15 yr old would have done .. not necessarily what the professionals would have used.

[marc_reusser]

Ray, dont know about smaller smoke jacks, but metal stacks that I have seen on old corrugated industrial roofs often had a square/rectanguler sheet mateal flange. flashing at the base of the stack where it protruded out of the roofing. whenever possible this flange would lap over the lower piece of corrugated, and extent to lapunder the upper piece of corrugated. I have also seen corr. ruufing pieces notched at stacks and chimneys to specifically provide this type of coverage.

WHere no joint is near, and the lapping the flashing under is therfore not possible, I have seen the use of a diverter lip/edge at the piece above the stack location. This way the majority of the water run-off coming towards the stack was diverted....then at the stack, flashing itseld there was likely a asphaltic or bitumen type of sealer used as Ed notes.

There are other ways this can be done and flashed,...but this would likely all depend on the type of constructio/structure you are representing )IE. what was it used for..and how much did the owner want to spend or care).


M

[Ray Dunakin]

Thanks, guys!

In this case it's on an old shack so I probably don't need to be too particular about it anyway.

[NORCALLOGGER]

Ray,
Depending of course on the wealth of the installer there were/are a couple of better ways to do roof flashings.

The easy/cheap ways have already been discussed.

The correct ways however were/are.

Use a section of the roofing, corrugated, box rib, whatever and build/solder the jack into the roofing section then
cut the sheet and slip your jack into the pattern in the required place.

For tile, slate, concrete tile etc. use a lead skirt on your sheet metal jack.
The lead will roll and conform to the contours of the tile.


Don't claim to be an expert but have built and installed literally thousands of
roof jacks on all kinds of roofs through the years.
Later
Rick

PS
Just occured to me, if you go back and look at my Marion Shovel thread
you will see in the last pictures the roof jacks made with the corrugated skirts.