Insert installation debris

Ctwoodtick

Minister of Fire
Jun 5, 2015
1,154
Southeast CT
Over time I’ve had a couple different chimney sweeps install (and then reinstall) my wood insert. First one was a hack job and the second one corrected those issues. Currently, there is a fair amount of masonry debris remaining on the smoke shelf from removal of firebrick and masonry near rear damper along with small bits and pieces of old clay liner that was broken out. Basically It’s a mix of different types of masonry broken up together in a dusty pile up there on the smoke shelf. Would have been nice for installer to have removed but didn’t happen.
Masonry chimney built in 1977, and I’m not sure if any of this masonry could have contained asbestos. Forgive me if this is a silly this is silly question altogether, but I’m wondering if I should remove this debris or just leave as is. Access is a bit difficult with insert in place and I anticipate that removing it will be challenging and a bit dusty on its own. Been running the insert line thus for a few years but just thinking of it now. Thanks.
 

begreen

Mooderator
Staff member
Nov 18, 2005
80,791
South Puget Sound, WA
I'd leave it. Sounds like there isn't a block-off plate in the damper area. Is this an exterior wall fireplace or interior? If exterior, adding one will improve heating.
 

Ctwoodtick

Minister of Fire
Jun 5, 2015
1,154
Southeast CT
I'd leave it. Sounds like there isn't a block-off plate in the damper area. Is this an exterior wall fireplace or interior? If exterior, adding one will improve heating.
Back of chimney is in garage so technically exterior. With the removal of the back firebricks in fireplace, there is very uneven surface to put a blockoff plate in. I like the idea a soft blockoff plate that was recently posted about but not sure if that method would work here. Also I’d want to do a two piece block off so that insert does not have to get pulled.
 

begreen

Mooderator
Staff member
Nov 18, 2005
80,791
South Puget Sound, WA
2 piece is fine. A block-off plate can be done lower down if there's room. It can even be 3 piece with the third piece acting as a patch to cover the area with the removed brick.
 

Ctwoodtick

Minister of Fire
Jun 5, 2015
1,154
Southeast CT
2 piece is fine. A block-off plate can be done lower down if there's room. It can even be 3 piece with the third piece acting as a patch to cover the area with the removed brick.
Thanks for that feedback. Can the silicone ( or what ever sealant used) be used liberally in areas where some gaps exist in the masonry? The back of the masonry firebox where I’d be attaching the blockoff plate is pretty jagged with that layer of firebrick removed ( what is behind the bricks looks like mortar which is pretty uneven). Thanks.
 

begreen

Mooderator
Staff member
Nov 18, 2005
80,791
South Puget Sound, WA
Yes, just not around the actual liner pipe. Wire brush the fireplace surface first for a good seal.
 

Ctwoodtick

Minister of Fire
Jun 5, 2015
1,154
Southeast CT
Yes, just not around the actual liner pipe. Wire brush the fireplace surface first for a good seal.
Terrific. Do you think that foil mineral product mentioned in the other thread could be done in 2 ( or 3 pieces) as well. If so, I’d be inclined to use stove gasket material around liner to seal that area up. Would that work you think?
 

begreen

Mooderator
Staff member
Nov 18, 2005
80,791
South Puget Sound, WA
Metal is better for a solid, mechanical, overlap joint. I am not sure how well the best aluminum tape would stand up from the heat in the cavity above the insert. Looking at the picture of the Roxul foil material around the flue liner, it looks pretty snug. I don't know if I would worry too much with that tight a fit.
 

Ctwoodtick

Minister of Fire
Jun 5, 2015
1,154
Southeast CT
Metal is better for a solid, mechanical, overlap joint. I am not sure how well the best aluminum tape would stand up from the heat in the cavity above the insert. Looking at the picture of the Roxul foil material around the flue liner, it looks pretty snug. I don't know if I would worry too much with that tight a fit.
I will try the sheet metal as block off ( with roxul above) and let you know how it goes. Thank you for the help.
 

begreen

Mooderator
Staff member
Nov 18, 2005
80,791
South Puget Sound, WA
Make cardboard templates first. Much easier to work with and adjust. Once the fit is good use the template to trace the outline onto the metal.