[acg]

Hi,

We are building a wood-fired salt kiln. We have some descriptive information for cutting and building through the shed roof, but we have not come across good pictures. We'd love to see pictures from underneath and above if possible. We're looking for how you support the cut out and also, flashing methods. We are in western Oregon and get LOTS of rain and need to prevent it pouring down the sides of the chimney.

Thanks

acg

[Seasoned Warrior]

I live in Northern California and while we don't get quite as much rain as you do we still get a fair amount. I don't have pictures immediately available but this should not be a problem for any competent sheet metal fabricator and most towns have at least one or two. My town has about 4000 people and we have two sheet metal shops. My chimneys have two rain sealing components. The first is a roof jack (technical construction term here) and the roof jack sits on the roof and tapers up to the chimney keeping a distance from the combustible parts of the roof and is designed so that there is a flat piece that sits on the roof plane and then a tapered funnel-like piece that goes up to the chimney. Since the roof jack doesn't fit tightly enough to seal the chimney there is a storm collar that fits on the chimney and looks a little like a funnel that attaches to the chimney and extends beyond the roof jack so that any rain runs down the chimney, runs onto the storm collar and drips onto the roof beyond the opening in the roof jack.

I've attached a photo of a typical installation. You can see the roof jack sitting on the roof and covered with the shingles and then the little hat brim shaped item above the roof jack is th storm collar. I'm out of my area and can't get you a photo of my exact set up but this should give you a basic understanding of the system I use. Let me know if I can e explain further.

Best regardes,
Charles

Attached File(s)

•  roof jack.jpg (18.63K)
  Number of downloads: 16

[acg]

Thanks,

We are building a fire brick chimney through a metal roof. I guess I should have been more specific.

I really appreciate your time and input.

acg

[Seasoned Warrior]

 Cricket.jpg (98.67K)
Number of downloads: 11

acg, on 03 October 2010 - 05:16 PM, said:

Thanks,

We are building a fire brick chimney through a metal roof. I guess I should have been more specific.

I really appreciate your time and input.

acg

A steel roof and a brick chimney makes a bit of a difference. You still don't tell us if it's a standing seam roof or a corrugated roof but I've attached a detail. In this detail it is a standing seam roof but it could be readily modified for a corrugated roof. with a corrugated roof you'd need to make a small well caulked gutter at the base of the cricket and use a closure strip (a type of seal for corrugated roofs) to divert the water from the corrugations. The closure strip wold keep the water from backing up through the high corrugations. If you need some specific advice send me a picture of the roof where the chimney penetrates.

Best regards,
Charles

[acg]

Seasoned Warrior, on 03 October 2010 - 09:05 PM, said:

Cricket.jpg

acg, on 03 October 2010 - 05:16 PM, said:

Thanks,

We are building a fire brick chimney through a metal roof. I guess I should have been more specific.

I really appreciate your time and input.

acg

A steel roof and a brick chimney makes a bit of a difference. You still don't tell us if it's a standing seam roof or a corrugated roof but I've attached a detail. In this detail it is a standing seam roof but it could be readily modified for a corrugated roof. with a corrugated roof you'd need to make a small well caulked gutter at the base of the cricket and use a closure strip (a type of seal for corrugated roofs) to divert the water from the corrugations. The closure strip wold keep the water from backing up through the high corrugations. If you need some specific advice send me a picture of the roof where the chimney penetrates.

Best regards,
Charles

[acg]

Hi Charles,

Thanks so much for your persistent in helping us. The illustration will help for the outside. We have to reinforce the inside where we go through the rafters. Do you know if any good construction site we could look at.

Thanks again for all of your help

act

[Seasoned Warrior]

acg, on 08 October 2010 - 11:34 AM, said:

Hi Charles,

Thanks so much for your persistent in helping us. The illustration will help for the outside. We have to reinforce the inside where we go through the rafters. Do you know if any good construction site we could look at.

Thanks again for all of your help

act

Afraid not. But usually you double up the rafters and double frame between the rafters with whatever the size of 2x you use for the rafters.

Good luck.

Best regards,
Charles

[JBaymore]

With a wood kiln, because of the typically higher than usual chimney temperatures, use metal studs for the framing surrounding the hardbrick chimney. Keep your clearnces to ANY combustables to minimum of 3 feet. Design the area for good active airflow around the chimney penetration point. Inspect the area during and at the end of every firing, and also well AFTER the kiln is shut dfown.

best,

...............john

[Seasoned Warrior]

John makes excellent points. I personally like steel but it is usually outside the scope of the skill-set of most amateur builders. My own kiln is under a free standing steel roof (standing seam) supported by steel columns and framed with 4" X 6" steel tubing on 12" X 12" steel colummns I managed to acquire from a salvage yard at very reasonable prices. However if you go the steel route you need to be able to weld to AWS D1.1 (American Welding Society specification D1.1 for structural welding) and build to the specifications contained in the American Institute of Steel Construction, Steel Construction Manual, 13th edition. Both the AWS and the AISC have websites with a lot of information.

Additional information can be found in ACI (American Concrete Institute) publications as well as CRSI (Concrete Re-inforcing Steel Institute) which will show you details of acceptable footings and moment connections for the steel columns. I would strongly recommend that you get the services of a professional, especially if you are going to have to deal with elevated temperatures in the area of the penetration. You will have a lot of weight subject to wind and other kinds of loading and all the connections must be properly designed for the type of structure as well as your particular geographic area.

Good luck,
Charles