Chase ventilation in SS lined masonry chimney?

[mossycup]

I just found some interesting info on venting the top flashing or top plate region when installing a stainless liner into manufactured chimneys.
In our case, we are installing damper block off plate as well as a top plate that holds the pipe in place. I am insulating the single wall liner (outside wall chase) and was planning on using silicone on all the top connections; plate to clay tile, pipe to plate, etc.

Without any way for the air around the liner to move in and out of the chase am I inviting condensation and dampness inside the clay tile, or even draft altering conditions?

 

[Renovation]

Hi Mossycup, and welcome.

My understanding is that venting won't affect your draft, but yes, would help condensation, water leakage, etc, to get out of your chimney.

I'm guessing wetness in there would be more of an issue in the off season. I'd also guess that masonry would be pretty tolerant of dampness, but why take a chance? I've seen an installation guide that specifies slots or a spacer between the top of the chase and the cap, with the cap overhanging so water drips away--that's what I suggest.

HTH, and good luck!

 

[mossycup]

I kind of wondered if this might be the case in the summer. Although it's brick and is tolerant of high humidity I figured it would keep any excessive condensation from accumulating inside, leading to degradation over the years.

 

[Renovation]

I kind of wondered if this might be the case in the summer. Although it's brick and is tolerant of high humidity I figured it would keep any excessive condensation from accumulating inside, leading to degradation over the years.

Yep, that's what good building practices are about--not finding out 15 years from now that something is wrecked for lack of a simple preventative step.

There's also the possibility that moisture could freeze and crack the brick, yada yada yada. Why risk it!

HTH, and good luck!