Chimney flue addition - mortar or cement?

[Bob]

I would like to add a chimney tile to the top of a chimney. This would probably involve setting the tile on the bricks with a little mortar, and tapering up the outside an inch or two from the outside of the brick chimney. A chimney sweep said to use cement mix to do this. The tile supplier said to use mortar mix. It seems to me the mortar makes more sense, but I would be interested in more opinions.

Bob

[Tim J. Johson]

You are probably getting mixed messages, because, well, it is a mixed message. I am not sure what you are asking, but if you are asking about adding to the outdoor crown of the chimney, a cement-like mix specifically for chimney crowns is usually what is recommended....thus the cement comment. Mortar is recommended for other parts of the chimney.

And, there are a number of different types of mortar. Type S gives pretty good compressive strength and great bonds and is usually sought for tall, unsupported chimneys.

Type N is usually used for general chimney work.

Crown mix is a concrete product, with other stuff mixed in (I don't remember what...), but it primarily just sits on top of the bricks and protects the "crown" of the chimney.

Anyway, I would recommend that you find a local firm that supplies concrete blocks and mason supplies for your area....look in the yellow pages under the concrete headings and drive over in person and present your question to someone at the counter who knows what they are talking about. They should know the answer, as well as have the stuff on hand that you need....you may pay $5-$10 more than at Home Depot, but you will get the right stuff.

BTW, as long as you are there, might ask about waterproofing your chimney. It will add years to the life of it....

[Bob]

Thanks. I appreciate this information.

Bob