Ask The Crusader!

Michael King...THE HOME IMPROVEMENT CRUSADER!

Brick Fireplace / Chimney

QUESTION
A lot of hot air is coming down my fireplace flue, even with the damper closed. How can I stop it?

ANSWER
Air coming down the chimney is called reverse chimney effect when the air pressure indoors is lower than that outdoors. To stop it, you can block off the firebox opening, making sure it is very tight and well gasketed.

Or, cut a piece of 1 – or 2 –inch Styrofoam insulation in the fireplace throat, below the damper. Still another way is to install a top-of-the-chimney damper on the affected flue. You can’t do this if there is a steel chimney cap up there now. And such a damper, which is controlled by wire going down the flue and into the fireplace, cannot be installed on an automatic heater, such as a gas- or oil-fired burner. Finally, several votive candles or a kerosene lamp set in the fireplace will get the air moving.

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Question
My brick fireplace wall is 10 feet wide and 81/2 feet high. I want to cover the brick with drywall, and then put on a mantel. I am chemically sensitive so I cannot glue strapping to the brick. How can I secure it?

Answer
You could do it one or two ways. Use 1x3's strapping vertically, and secure them with Molly bolts. Drill holes in the mortar and insert the Molly bolt, which will expand in the hole as you drive it in. If you want a bit of insulation on the wall, insert ¾ inch Styrofoam or Thermax between the strapping. Cover with drywall and paint with a safe latex. Or use 2x3's on the wide side, and use 2x2's as a top and bottom plate. Any stud wall will do, and the bottom and top plates can be nailed to the floor and ceiling respectively. The insulation will be thicker in such a stud wall.

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Question
Should I have a masonry sealer put on my brick chimney? If so, then why? My chimney sweep recommended a chimney cap. Why?

Answer
If there are no leaks in the chimney, there is no need for a sealer. Besides, a masonry sealer on a chimney can trap water vapor and water behind the brick, not only causing leaks but causing bricks to chip. Paint will do the same thing. As for suggesting a chimney cap, if there is no water, birds or other critters coming into the chimney and the chimney is operating properly, there is no need for a cap.

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Question
My brick chimney is bulging where it goes through the attic, but not above the roof. What is wrong and how can it be fixed?

Answer
If the bulge is solid and does not move when you really lean on it, there may be nothing structurally wrong with it. The heat of the attic might have caused the bulge, which can happen naturally. Have a mason inspect it. It is possible that the chimney should be rebuilt from the attic floor up. It probably does not have a flute liner, either, and this would be the time to put a stainless-steel liner, especially if the heat with gas.

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Question
My 30-year-old house has a yellow brick fireplace wall that is curved. I saw a program that put joint compound on the brick for a plaster look, but I did not see how they did it. How can this be done? Can I paint the brick?

Answer
If the brick and the mortar joints are relatively rough, the joint compound should stick quite nicely. Why don't you call the TV program and see exactly how this was done? If you want to change the color of the brick, you can paint it (Be sure this is what you want because it's very difficult to remove). To paint, clean with a strong detergent solution, let dry, apply one coat of latex enamel undercoater (Primer Sealer) and finish with one coat or two coats of flat latex wall paint. Remember thin coats work better than thick coats.

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