Attaching the Duratech anchor plate & sealing chimney to exterior frame

Hello. Should I be applying the entire tube of RTV High Temp Silicone to attach the anchor plate? Should I smear it all around and over the edges as best I can?

Regarding the anchor points, the directions clearly say to NOT use anchor screws (tap-cons), but I noticed they have been used or recommended by others on this forum, or is it not applicable to the Mattone Cupola ovens as the 2 coats of stucco will be enough?

Also, for the outside of our oven, we are building a square frame enclosure with an “A” frame roof that will be finished in stone veener. What is the best way to seal around the chimney stack as it exits thru the center of the “A” frame roof to avoid any moisture from entering? Would Rutland Furnace Cement be a good product to use in this case?

Hi Andrew,

You’ll end up using most of the adhesive. Following the instructions and applying to both chimney and plate, I found the tube was almost empty when I was done. The goal is to make a smoke-tight seal (almost like a gasket) so you do need to apply it liberally. I actually ran a bead around the edges to complete the job and keep water/ice out of the plate.

Applying TapCons was in the original instructions. @BrickWood took it out because too many people were applying them too enthusiastically and breaking the mortar of their chimney caps. You can still use them provided you drill the anchor holes carefully and straight down (no wiggling). They have been problematic in the past so my advice is to use great caution if you do use them.

As for your A frame, yes, that would be a good product. You can also use a small batch of the heat resistant mortar as long as you waterproof it.

Good luck with your chimney!

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