Around the house: Converting wood fireplace to gas, and fixing a crumbling chimney

Dear Ken: I have a wood-burning fireplace that I want to convert to gas. What are the pros and cons? How much should it cost? - Nancy

Answer: Wood burners like yours send most of the heat up the chimney. By contrast, their modern, energy-efficient cousins - sealed gas log fireplaces - keep much more heat inside the house by circulating room air through a venting system around the firebox.

The most expensive part of the installation is running the gas line from an existing pipe into the fireplace. This is best left to a professional gas contractor or plumber who will buy a permit from the city and get the requisite inspections. They'll also hook up the gas log you provide.

Two other components are required by the code. A small, hold-open clamp must be installed on the fireplace flue damper - up high inside the chimney - to allow fumes from the perpetually-burning pilot light to escape. You'll also need to buy a set of glass doors to keep room air from escaping up the chimney when the gas log is idle.

Gas piping costs vary a lot, depending on how far the pipe has to be run. Figure on several hundred dollars. The gas log set will cost $200 to $500, depending on the size.

Dear Ken: I recently hired a local company to repair the chimney. The cap was falling apart, and the top layer of bricks was loose. The estimate was to relay the bricks. When they got up there, all they did was tuck point. Should I be concerned? - Mitch

Answer: Tuck pointing is the way we replace mortar between bricks that has sloughed off. We use a special pointing tool, or sometimes just a gloved finger, to shove mortar back into the cracks. Loose bricks that can be pulled off the chimney should be reset with that same mortar by troweling on a new layer and then setting them back in place. In your case, the terms are sort of interchangeable. For instance, some bricks may not have been as loose as they thought. As long as they guarantee that all the bricks are tight and secure, no problem.

Incidentally, the mortar cap atop a masonry chimney often can be repaired rather than replaced. All of these caps develop weathering cracks, but they can be filled in with clear rubber silicone over many seasons before the cap must be replaced.

Dear Ken: Our house has a steel beam running the length of the basement. It has begun to twist in the middle, and the steel jacks underneath are angled. A contractor suggests straightening the beam, then welding solid pipe from the jacks to the beam itself. Is that an OK fix? - Glen

Answer: This is a fairly common problem. Steel beams and their posts carry their maximum designed load only when they're plumb (straight up and down). When the folks who install these systems are in a hurry, they can get some posts slightly off center on the bottom of the I-beam. That introduces a rotating force that can eventually start to twist the beam. The contractor may be able to simply remove the load temporarily, straighten the beam, then reinstall the posts, centered, the way they should have been in the first place.

Welding a fixed steel pipe in place would be a last resort. Why? It will prevent future adjustments if the posts start to shift or settle.

Dear Ken: Our basement flooded, and now the bricks on the fireplace have a water mark. How can we clean it? - Andy

Answer: Use a stiff bristle brush and scrub with some diluted (powdered) dish washing soap or TSP (tri sodium phosphate, a strong cleaner you can get at the hardware store). If you still see a stain, try an acid treatment, using white vinegar and the same brush. Brick is pretty porous, so don't be surprised if you can't remove every last bit of the residue. But these treatments should help it fade away.

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