Metalbests roof support instl help

[brider]

I'm looking at the S-4 instruction sheet for the Metalbestos roof support kit, and have some basic questions that really apply to any similar installation:

Do I install the roof support, THEN determine what length connector I need from the stove collar to the ceiling support?

The instructions say " twist lock additional lengths of chimney to top of assembly pipe to required chimney passes through roof and at least 2 feet higher...". This is verbatum from the instruction sheet, I assume it is just saying to NOW install the required height of chimney pipe. My question is the "twist lock" statement; do all chimney pipes have a twist-lock feature?

 

[fossil]

Dunno all the answers, brider, just givin' yer post a bump. When I put in my shop stove, the adapter, support box and chimney were already in place, so I just had to set the stove in place and assemble the rewuired connector pipe arrangement. With a slip fitting incorporated in the run, it was straightforward. The pro installer who put my Lopi in completed the support box, roof penetration, and chimney before he installed the connector pipe up from the stove. Chimney piping...all I can tell you is that Simpson Dura-Vent twist-locks together, with no additional banding or clamping. I gather that there are other brands that might connect together differently. Rick

 

[BJ64]

I'm looking at the S-4 instruction sheet for the Metalbestos roof support kit, and have some basic questions that really apply to any similar installation:

Do I install the roof support, THEN determine what length connector I need from the stove collar to the ceiling support?

The instructions say " twist lock additional lengths of chimney to top of assembly pipe to required chimney passes through roof and at least 2 feet higher...". This is verbatum from the instruction sheet, I assume it is just saying to NOW install the required height of chimney pipe. My question is the "twist lock" statement; do all chimney pipes have a twist-lock feature?

I can help!

I just did an install the other day which required some research in chimney pipe. Twist lock feature depends on the brand. Desa brand double wall pipe pushes and sorta snaps together (6-inch inner diameter by 10-inch outer diameter, non insulated, instead has 2-inch air way between the inner and outer pipe). Rick mentioned his brand was twist lock. I can vouch that MetalFab and SuperVent brands also twist lock. SuperVent pipe has a simple little band to keep the joints from coming untwisted. According to how I read the book, SuperVent's band is only required on connections above the roof line but can be used on all connections.

I used the SuperVent pipe.

For clairfication - I am defining the roof support as the black device seen above the stove that attaches to the ceiling and looks sorta like a simple light fixture.

Install the roof support first.

In the case of using SuperVent - set the first joint(s) of pipe into the roof support. At this point just install the entire chimney if you want and be done with all the roof work. Put the connector pipe adapter in place. It will twist lock in from the bottom of the roof support which is above the stove. Put the stove adapter on the smoke outlet of the stove. Put on your Super Man cape and scoot the stove in place (don't forget to tie your shoes). This will show you how much connector pipe is needed.

MetalFab pipe is similar. I just don't know how the connector pipe adapter goes on. I am led to believe that the roof support has the connector pipe adapter made into it.

At this point I wish to recommend one joint of telescoping connector pipe in addition to any standard lengths if needed. Some telescoping lengths are good from 30-some-inches up to 68-inches. It makes installing the connector pipe a quick, easy, and neat looking job. If you need to dissconnect the pipe, for cleaning as an example, the telescoping pipe makes that job so much easier as well.

Also, remember to ask if a stove adapter is needed for your connector pipe.

Also again, check the stove manual. It may have a minimum length of pipe required to produce enough draft to operate. My Lopi Leyden required 15-feet of pipe. I assumed this length was measured from the stove top to the chimney top. In any case i have 6-feet of chimney pipe towering over the house. My wife declared it to be a lightning rod. My kids what to install a blinking light on it.

I just hope I don't have to chase bats out of it.
https://www.hearth.com/talk/threads/23282/

 

[BJ64]

Just bumping the topic to see if it needs more input on the matter.

 

[KeithO]

Install the stove first, or at least determine exactly where the stove will be located in order to meet clearance requirements. Then evaluate options for placement of the chimney above the stove (assuming a ranch style house) in relation to roof truss locations.

"Chimney" refers to Class A insulated pipe, not air gap, nor stove pipe. The Chimney has to be UL listed to type 103 HT which requires that it be able to withstand a 2100 degree F chimney fire twice for a certain duration of time while meeting surface temperature requirements. Usually, class A pipe has a clearance requirement of 2" to combustibles. If it is a 6" class A pipe, the OD will be at least 8" taking the insulation and double wall into account. So adding 2" per side for clearance the total diameter of clear space required for instalation is 12". It is no secret therefore why the ceiling support boxes start with a 12x12" dimension. For obvious reasons, if your roof trusses are 16" on center, that 12" ceiling support box will only have a bit of wiggle room between the trusses. Most homes have 24" truss spacing so there is typically a bit more wiggle room, but never much more than +- 5" from the center between 2 trusses. For this reason, and because of that fact that a straight chimney is less expensive, less complicated to install and simply work better, it is better to choose the best chimney location for the straightest simplest install. Then take up whatever offset (if any) in the single or double wall "stove pipe" (not chimney) from the ceiling support to the stove.

Many types of class A have a bayonet style coupling between pipe sections. In general, these fit pretty well (accurately) and the band clamps are much nicer than screws for fastening the sections together. No drilling holes, and no additional points for water ingress. Typically, you use an attic radiation shield to keep insulation the requisite 2" away from the chimney.

If you have more questions, just ask

I'm looking at the S-4 instruction sheet for the Metalbestos roof support kit, and have some basic questions that really apply to any similar installation:

Do I install the roof support, THEN determine what length connector I need from the stove collar to the ceiling support?

The instructions say " twist lock additional lengths of chimney to top of assembly pipe to required chimney passes through roof and at least 2 feet higher...". This is verbatum from the instruction sheet, I assume it is just saying to NOW install the required height of chimney pipe. My question is the "twist lock" statement; do all chimney pipes have a twist-lock feature?

 

[brider]

Just got back to this thread, thanks all for the great help/advice.

I've spent the last 2 days researching the Selkirk (Metalbestos) website and downloading instruction sheets that were MISSING from the big "kit" I bought with the stove. I had panicked a little bit a few days ago when I first looked at the parts, most with no part numbers, and realized there was a WHOLE BUNCH of missing info. Now that I've studied it, it's a really straightforward procedure. I bought a 6' length of galvanized duct from HD, stuck it in the stove vent collar, and painstakingly ran a level up 4 sides to get a plumb sketch of where the 6" hole pierces the roof (it's a cathedral ceiling).

BEFORE I and 3 other guys wrassled the stove in place, I plotted out the location of the stove on the floor, took the dimensions of the stove and location of the stove collar (from the manual), and ran a plumb bob up to the ceiling to get a centered location between joists. With the stove in place and markings on the ceiling, it looks like one of the sides of my 12 x 12 box will be an existing joist, DEAD NUTS, so my positioning could not have been more perfect. WHEW!

Cut the first undersized hole in my ceiling tonight. I feel better now.