Bricks, Masonry, Asphalt and Concrete - Chimney Plans?

Posted this over in Fireplaces & Chimneys but not a lot of action there.

I want to build a simple chimney for a woodstove. Something like hollow 12x12 (or so) cinder block with the flue pipe running up the center, and a cleanout. Does anyone have a link to plans for something like this? My Google search was unfruitful.

Did you check home depot and lowes for books also your library. They did make a 16X 16 cement block unit that a clay flue fit into. Dont know if you can find it there. Are how about a metal flue for the stove there . They have them for wood stoves.

ED ;)

Did a little searching since I could not find anything before when you posted in Chimneys. This may or may not help but it covers a lot of types of installations. Good luck.

http://www.hearth.com/what/installstove.html

Haven't checked for books yet - thought I'd start here first. The 16x16 block hollowed for a clay flue is exactly what I'm talking about. The only thing I'm not clear on is how to incorporate a cleanout at the bottom.

Check your local codes and insurance requirements before doing any chimney work for woodburners.

Some insurance companies will only insure masonry chimneys (no metal in any form) that have been looked at. Others have varying degrees of requirements.

Local code or requirements also vary widely.

Chimney construction can be a sophisticated as you want it and depends on what you will be burning and how hot you want the fire to be. When you are just burning a rediculous amount of fuel continuously you can get away with a lot. Cooler, efficient fires that are used infrequently require a better chimney since the chimney performs better when it is continually kept warm.

You probably are considering either an 8" round or 8" square chimney flue. Use refractory mortar between the flues.

Surrounding this, you can use a chimney block or brick. The chimney block is usually about 16 3/4 inches squre and has an outer wall that looks like the cores of a 4 inch block. Try to use lighweight concrete to save your back and get a better chimney.

I assume you are in a cool area, so having a space between the flue and other masonry is needed for expansion. Never put solid mortar between the flue linner and the brick or chimney block. An gap is needed to prevent the expanding hot flue from splitting the cold masonry exterior. Some concerned masons even fill the gap with insulation such as vermiculite or perlite (not foam). This helps keep the flues warm and maintain a draft when you have a low fire in a cold climate. This decreases cresote build-up.

You should use a flue tee or a "thimble" where the horizontal metal pipe enters the chimney. Leave the bottom of the tee or vertical flue open so the ashes and creosote droppings can fall down to be collected.

Install a clean-out door at the bottom of the chimney so you can clean out the droppings that accumulate. The droppings will be ash or creosote that never got carried up and out of the chimney or they may be pieces of creosote that collected on the cool flue and fell off as the flue heated up. Also, you will get the droppings whenever you clean the chimney.

It is scarey to see how much potential chimney fire fuel you can collect at the bottom. Avoid fuel with a lot of sap and moisture. This compounds the problem.

The adove was for a chimney that has an exposed area at the base to give you access for a clean-out. It is not a pretty sight when you don't have a clean-out and have the bottom 8 feet of a filled area below the tee literally explode and remove a portion of the building before the fire got to the rest.

The creosote creates an acid when it comes into contact with moisture (rain or condensation) that can rust metal unless it is good stainless. Galvanized screws will disappear when the acid eats through the zinc that is scraped off during installation if you use a tin chimney.

For local information I think Peerless Block in St. Albans makes block and probably sells chimney material. Other good sources would be local brick or masonry supply outlets. They usually sell the flues, mortar and clean-out doors.

For other technical masonry information, go to the NCMA (National Concrete Masonry Association) site. Look for the technical information or TEK Notes. You will have to hit an identifying state to go through a member's access point. I assume they want to know where the hits are coming from.

Good luck!!

Dick

Thanks for the comprehensive reply. What you describe (with the chimney block) is what I'm looking to do. I'm familiar with woodstoves, having had one in a log house I used to own, and a pellet stove in another. I also used to cut my own wood and do my own chimney cleaning and maintenance, so know all too well how much creosote can build up. I plan to burn only hardwood that has seasoned for at least a year. A pellet stove would surely be easier I know, but the wife doesn't like them.

My current house is a block and stucco rancher with a walkout basement, located in the Eastern Panhandle of West Virginia. It has oil heat. I want to add a small woodstove (probably an airtight) in the finished basement and run the chimney outside up the back wall of the house where it won't be seen (though I may later face it with fake stone or something). There is no intent to heat the whole house this way, just to make the basement family room and my wife's art studio a bit warmer. I want a full masonry chimney, probably with the 8" square flue.

I'll certainly consult a local pro before starting this, as a couple of construction details are still unclear to me. First, I presume I'll need a footer of some sort? I thought maybe just digging down to below the frost line (28" here) and pouring a small slab would work. Since the basement is a walkout, I wouldn't have far to dig. Also, it's not clear to me exactly what would support the flue pipe. I know the tee would be supported somewhat where it passes through the block and into the house, but I can't imagine that'd support the weight of the entire flue.

Well, I checked Lowe's and Home Depot and neither had any books to help out with this. Are there no plans for something this simple?? Do masons just build as they go?

I am not surprised about Lowes and HD, since they know a lot about the stuf that burns, but little about masonry.

I would try to find a local masonry supplier since they would be looking for a customer and know about local requirements.

Sorry about leading you toward the western frontier for a supplier. If you are in the far eastern end and can't find a local supplier try calling either Supreme Concrete (office in Hagerstown and a plant in Winchester, VA) or Hagerstown Block in Hagerstown, MD and Marshall, VA. They probably have some dealers and can tell what chimney block are locally available.

Good luck.

Dick

OK, thanks. There's a couple of masonry places in Frederick MD (where I work) so I guess I can start there.