Caulking Help!

[s219]

I am finishing up my generator shed (full details to come) and put on an exhaust chimney yesterday. It's a typical arrangement that would be used for a gas hot water heater or furnace, with a metal cone, pipe, storm collar, and cap, all galvanized steel. I caulked around the cone/pipe joint and collar/pipe joint yesterday afternoon when temps were mild. I used DAP Alex Plus caulk, which I have had great luck with over the years.

Well, rain arrived earlier than expected last evening and has been a lot heavier than expected (I should not be surprised -- we've gotten swamped over the last few weeks). This morning I see that the caulk has partially washed away and run down through the joints along the pipe and is dripping inside the shed. Obviously it never had a chance to tack up at all.

It's supposed to rain all day, as temps drop from the 50s to single digits overnight. I am thinking I will try to wipe up all the wet caulk when I get home from work this evening, before the mess freezes up. Then we have a couple days well below freezing, then warmup into the 40s on Thursday just in time to bring more darn rain.

Any suggestions for a caulk product that I can apply which will be more rain resistant? Looks like my next opportunity to caulk in above freezing weather will be Thursday with temps in the 40s, but "chance" of rain moves in that evening and exists for three days after that.

I can possibly throw a tarp over the chimney to try and keep it dry, but who knows if that will really protect it enough if we get heavy rain again.

 

[ray66v]

Sounds like you used "B" vent, double walled pipe?

They make silicone in silver color, for calking galvanized pipe.

I recently bought some at Lowe's.

You can use any color you have.

Latex calk should not be used for anything, other than sealing gaps in wood.

 

[/pine]

You're sealing roof penetrations with calking?...did you use vent/pipe stack boot flashing's?

Hard to find a sealant that works in really cold WX...you might find some self adhesive rubber roofing patches...or some scraps of torch-down bitumen roofing...(can be applied with small propane torch)

 

[randy41]

the caulk doesn't cure very fast when its cold out. i use the plastic roof repair stuff. the black gooey stuff. it works best when its warm out too.

 

[Baby Grand]

^ copy what randy said.
Make sure you wear clothes that you don't mind getting black smudges on.
That stuff is worse than the silver colored anti-seize stuff.

Boot flashing, as /pine mentioned, will make the job a long term survivor.

Look forward to seeing what you came up with - will there be pictures?
We have an old dog house that I've been thinking would just about fit over the Trailblazer.
Do you need to vent it so it doesn't overheat?

 

[s219]

You're sealing roof penetrations with calking?...did you use vent/pipe stack boot flashing's?

Yes, there's a boot that was lapped in under the shingles. The only places needing seal are the joint where the pipe passes through the boot and the storm collar that sits right above that. Very small gap really.

 

[s219]

Sounds like you used "B" vent, double walled pipe?

They make silicone in silver color, for calking galvanized pipe.

I recently bought some at Lowe's.

You can use any color you have.

Latex calk should not be used for anything, other than sealing gaps in wood.

Yes, double wall.

 

[tcreeley]

Get your flashing right. I use silicon caulk- even below freezing- works fine, water resistant. Use hi-temp silicon caulk for metal chimneys.

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[s219]

^ copy what randy said.
Make sure you wear clothes that you don't mind getting black smudges on.
That stuff is worse than the silver colored anti-seize stuff.

Boot flashing, as /pine mentioned, will make the job a long term survivor.

Look forward to seeing what you came up with - will there be pictures?
We have an old dog house that I've been thinking would just about fit over the Trailblazer.
Do you need to vent it so it doesn't overheat?

Yes, I have tons of pics with all the work, including electrical and fuel. This is a water cooled diesel unit, so we have one large vent louvre lined up with radiator outflow, then another in opposite corner for inflow. Plus, heavily vented soffits for general ventilation.

 

[/pine]

Yes, there's a boot that was lapped in under the shingles. The only places needing seal are the joint where the pipe passes through the boot and the storm collar that sits right above that. Very small gap really.

OK I understand now thanks...

I recently had to wait on the weather to replace a skylight dome because of the (sealant) curing temperature required...it should be listed on quality sealant tubes...

in a pinch where regular calking would suffice (heat wise etc)...duct tape can be used...I used it to make temporary step flashing ...(and it sticks in cold weather)...

good luck...