wood burning fireplace exterior vent

[CHARLIE VAN FLEET]

hey all

does this fp external vent look right thru roof

thanks
charlie

[A.D. Miller]

hey all

does this fp external vent look right thru roof

thanks
charlie

CVF: It all depends upon whose product it is. Here is one example:

http://www.duravent.com/docs/instruct/L119_Jan09.pdf

[H.G. Watson, Sr.]

No it doesn't "look right".

Wood burning FP or stoves should have a Class-A Chimney (UL 103HT). Class-A Stainless Steel Chimney has a 2" clearance to combustibles (chimney fire can reach +2,000 degrees F).

NFPA 211 might be helpful, it is available for free viewing on-line. Cold climates, chimneys mounted on an outside wall should be enclosed. Exterior chases reduce condensation and creosote formation, and enhance draft.

It is exposed for a significant developed length where winter design temps (colorado) before being hot spot boxed by the soffit. The exposed and apparently closed soffit appears in direct contact with the Chimney, there should be a radiation sheild there which also maintains clearance from combustibles. The blocking on the siding which is painted appears to be combustible and within the 2" minimum zone Metal strapping is usually used. I do not see support on the roof. The gutter seems very close in contact clearance to the exterior Chimney wall also.

For an example of a similar exterior installation and detail on the soffit radiation sheild see
Typical Installations of the EXCEL chimney (http://www.icc-rsf.com/en/icc/Typical_Installations_of_the_EXCEL_chimney)
exterior installation diagram.

Drafting problems and hot spots appear likely. Altitude/climate considerations. Down below the "flat" top of the chase around the firebox looks reverse sloped drainage/flashing/water-snow-ice-debris collections appear likely. B-vent even with SS liner shouldn't be used for solid fuel.

[Bob Harper]

Charlie, as with all appliances, you really need to record the make, model and serial number for all your answers. However, a few notes:
If this is a woodstove, it would need to comply with the local codes and the listed instructions and this chimney would need to meet UL 103HT.

If it is a factory built fireplace, it needs to meet codes and listing but instead of 103HT it would use the chimney tested and listed for use with that fireplace. Usually, that means that mfrs. own brand of air cooled chimney. Newer hybrid stove/ fireplaces may specific make, model and size 103HT chimney.

I agree with HG on questioning those clearances. Also, that doghouse flashing may or may not meet with the listing. If the listing requires the chase to breathe, it may be sealed too tightly. I highly recommend a Level II inspection.
Bob

[Mike Truss Guy]

One thing I would say is if the vinyl siding starts to melt it's probably too close to the wall no matter what the manufacture's specs say about clearances. ;)