Englander 32-NC: Earthbound home stability?

[s57nomad]

A cathedral ceiling support box gets hung between the rafters. It solves a couple issues because it can be hung plumb and is the trim + support, all in one. This is in lieu of the roof top support bracket, trim collar, and finishing collar.. Download the Duratech installation manual for more details. Note, the order is missing a storm collar. Also, save receipts. The DVL stove adapter is not needed for several stoves and a sloppy fit. In many cases the DVL pipe itself fits a lot better.

View attachment 343996

The hearth base needs at least an R=1 rating. What are the construction details for this?

I see now about the Cathedral Ceiling Support box. That is a more sound option. I do see the installation instructions now online and have downloaded them. I can remove the drywall and frame for the support box no problem.

Hearth base construction shall be:
- Steel studs on edge measure 3-5/8" tall (3-5/8" open space under Durock framed 12" on center for support)
- 3 layers of 1/2" Durock (plus thinset mortar)
- 1 layer of 1/2" ceramic 6"x6" tiles (plus that thinset mortar

All constructed will raise the stove off of the floor 6".

 

[s57nomad]

I'm so very glad for everyone's professional knowledge and input! I knew we had a ceiling gap of at least 12 inches to the roof sheathing above, but in fact we have 40 inches. I am so very grateful that this forum has helped me look further into the installation. I am a student of life forever!

It looks as though the installation of a ceiling support box is in order. According to DuraVent a shield or top cover will be needed for the Ceiling Support Box, though the space is unoccupied there is some blown in mineral insulation. I attached the excerpts for reference from the manual and also noticed the mention of Rockwool being used to fill the support box. Am I headed the right direction.

Thank you again all!

 

[s57nomad]

Student of Life right here! MY Perspective and pay attention may not be real strong tonight nor yesterday. 😆

 

[begreen]

Wow. Good thing to check first. The deepest cathedral support box is 36". It may need an extension to carry it up the underside of the roof. This will also act as an attic insulation shield. Be very sure that it is vacuumed clean before dropping the chimney pipe in place. It also sounds like an extra length of chimney may be needed depending on satisfying the 10-3-2 requirement above the roof.

 

[s57nomad]

Wow. Good thing to check first. The deepest cathedral support box is 36". It may need an extension to carry it up the underside of the roof. This will also act as an attic insulation shield. Be very sure that it is vacuumed clean before dropping the chimney pipe in place. It also sounds like an extra length of chimney may be needed depending on satisfying the 10-3-2 requirement above the roof.

Indeed! Absolutely glad we checked!

Yes the 36" support box will suffice. The DuraVent DuraTech installation guide states in "8-A":

"For a 6” Dia DuraTech Chimney system,
if the unoccupied space is immediately
above the square or round support box (if
used), the support box may be used as an
Insulation shield, using the included collar to completely cover the support box. If desired, non-combustible insulation may be inserted into the Support Box as described in step 3-A. Important: Ensure support box height is appropriate to cover current/future insulation
height."

Found on page 10 of the installation manual. All other references in the above photos were from the manufacturer installation guide.

I'm just thinking out loud here. Does it appear that I can use the 36" Cathedral Support box with the cover so long as any insulation will never touch any exposed pipe, so long as I reside here. No insulation to go over the top few inches of this box with the insulation cover installed EVER. I could in fact and would prefer to put the Rockwool ceramic insulation into the box to mitigate heat, cold, and condensation in the support box (states in 8-A of guide under step 3-A. Is this all agreeable?

3-A reads on page 9 of the installation manual:

"When installing a Support Box into a
roof, non-combustible insulation adhering to the specifications on page 4 may be added to prevent cold/outside air intrusion and limit condensation on the surface of the Support Box. Cut the insulation into squares as shown in Figure 9a, or wrap the pipe with an insulation blanket and fill in the corners as shown in Figure 9b. Do not compress the insulation more than 25% or you may adversely affect the thermal resistance of the insulation. Non-combustible insulation is allowed up to the top edge of the Support Box, but not go past the edge where it can fall out or come in direct contact with combustible materials."

 

[s57nomad]

Insulating the support box on page 4 reads:

"NON-COMBUSTIBLE INSULATIONS

Non-combustible insulation is tested and
approved through UL for use within the
clearance to combustibles distance between a passthrough leading to the exterior of a building, and only as described in these instructions. The non-combustible insulation used must be listed / compliant with ASTM E136/ULC S114 as non-combustible, have a melting temperature above 2000°F/1100°C, be water resistant with low mositure absorbtion and be acceptable to the AHJ. Acceptable insulations include those made from stone
(aka “rockwool” or “mineral wool” insulations).

Note - Fiberglass insulation is NOT
approved!"

I have Rockwool board for this purpose. Pictures attached.

Certification for the Rockwool 80 also attached for certification as it meets the ASTM E136/ULC S114 requirements.