Chimney top design

I have a older house built in 1851. I am not the original owner. It has three brick chimneys. A large main chimney with three flues and two single flue chimneys.

One of the single stacks, the unused one, was likely used for a kitchen cook stove and has not been in service since I have been here (12 years). The other single stack is currently being used with my Hitzer 50-93 and works fine as far as draft is concerned.

The single chimney that is unused was not finished off on top with a cap and has only a wooden cap that was put on to keep out the weather. The other two chimneys each have a built up brick support columns which support a slate cap. Those two chimneys are open on only two sides in that the brick is built up as a solid wall on two sides and an open section on the other two sides.

The question I have is I am in the process of building a brick and slate cap for the single chimney that was cap less. I was going to only build up the corners with support bricks thus leaving four sides of the chimney free to breath for draft. I got thinking of my two chimneys built by the old timers and wondered if there was a reason that they designed them with only two sides open for draft. Seeing that I was always day dreaming during school, especially during Bernoullie's principle of fluid dynamics, I am left wondering if I should rethink my design of the cap. Does anyone have any knowledge of this situation? Is the issue minor either way? Albeit I probably will not be using said chimney I'd still like to build it proper. It is not too late for me to add bricks if need be before I place the cap on.

A bit more, both of the chimneys that already have caps are not the same in so far as which sides are open to draft; i.e. the single has an east/west opening while the large main has its south/north side open.

Thanks

P.S. The 'original owner' comment was intended for humor. Hope you caught it.

Townsend wrote:A bit more, both of the chimneys that already have caps are not the same in so far as which sides are open to draft; i.e. the single has an east/west opening while the large main has its south/north side open.

My first thought was that they did it that way due to the prevailing winds and potential for a downdraft...but your last comment shot that theory to pieces. I think the chimney will draft fine with either design, so the choice is yours.

Maybe I'm being picky, but if it were my decision I would try to match the original brick color and replicate the cap style on the other chimneys.

More open area, the better. Caps are strictly to keep rain out. If nothing more, they impede draft. No design that I know of improves draft. You cannot rely on winds for draft.

Here is a picture of the 3-flue chimney on my grandfather's house...must have been put up by the same mason.

Townsend, I'm from coal country, coaldale PA. I'm a mason 41 years. Put a slate cap on your raised corners. Let four sides open for draft. That'l do it. Any more questions pm me. Den

I got it. I've put my share of chimneys up & my suggestion would also be to just lay the slate on the 4 corner bricks. If anything gets screwy, you can always brick up 2 sides at a later date--I suspect that that situation will not arise. Not a bad pointing job my friend.

Thank you all for the replies. I am keeping it open on four sides.

Rob, I did try to match it as best I could but I was going on memory. I agree that the photo looks odd and the bricks are a bit lighter in color. But, I think that shot was not the best representation. Not sure if it was early morning light combined with mortar residue etc. Here is a shot from the ground where most views will occur. I don't feel like redoing it so it'll stay that way.

I appreciate all the replies gentlemen.

Townsend wrote:I have a older house built in 1851. I am not the original owner.

I caught that. Good one

McGiever wrote:

Townsend wrote:I have a older house built in 1851. I am not the original owner.

I caught that. Good one

I been up since midnight and I caught that too -

and the same mason did my parents house - open on two sides with cap

Townsend wrote:I have a older house built in 1851. I am not the original owner.

You fooled me with that avatar!

geeezum, you New England guys--it took ya 21 days.