How to remove stain from wood furniture

Q. I am hoping you can help us. We have beautiful piece of oak furniture that has mold on it. Our cleaning lady was using a damp rag to clean the furniture and didn't dry it and placed books on top of the wet area. We now have an area exactly underneath the book that is black. Is there any way to remove this without damaging the wood any further?

A. Either the book was left on the spot for quite a long time for a dark spot to develop or the book cover was black and some of the color bleached out onto the piece of furniture.

If the dark spot is from the book cover, lubricate the spot with a bit of paint thinner and rub the spot with 0000 stainless steel wool following the grain of the wood.

If the dark spot is from moisture penetration of the wood grain over time, first try the same treatment, but if unsuccessful, rub the stain with Briwax and 0000 stainless steel wool.

If unsuccessful, try oxalic acid next. You will need a very small amount of the crystals, which you can buy in paint stores. Oxalic acid is very caustic, so wear gloves, eye protection and old clothes. Mix the crystals to saturation in warm water in a plastic or glass container; never use metal containers or tools with oxalic acid. Apply it to the stain with a small brush. Let it do its bleaching work. Then wipe off the residue with a clean cloth dampened in white vinegar and dispose of it environmentally.

And if that didn't do the job, the next step would be to buy a commercial bleaching agent and follow instructions on the container.

These treatments may remove any finish on the piece of furniture and leave a lighter colored area. The top may have to be refinished. You may need the services of a professional furniture refinisher.

Q. I am a designer north of Boston. I have recently renovated a 1960s ranch. We are under contract with our buyer and her home inspector claims we do not have proper venting.

Background: The width of the house is 48 feet (divided in half with 24-feet deep on the left and 28-feet deep in the right) approx. 1,248 square feet total.

• The original roof was not vented other than gable vents at each end.

• We stripped and replaced the roof. While doing so we added a ridge vent along the 24-by-28 half of the house.

• We also extended the overhang along the front of the house to incorporate and remove the roof over a bay window, while doing so we added strip soffit vents 2 inches by 8 feet along the entire 24-foot length coupled with the pink baffles - (same half as new ridge vent).

Note: Over the bay section ONLY is closed cell spray foam. The remainder of the house is fiberglass with R-30 in the attic.

• We have closed off the gable vents.

Our roofing contractor felt this scenario would provide sufficient air flow. There is no evidence of any mold or ice dams in the attic or perimeter. Do you feel we have sufficient air flow?

A. Thank you for the five photos, four of which look like they are of pre-existing conditions. The renovated house is beautiful.

Adding a ridge vent, which I hope is externally baffled to direct wind over the ridge, reduces the risk of snow and rain penetration and increases ventilation in strong winds, as well as continuous soffit venting and closing off the two gable vents was the right approach to the best natural attic ventilation.

But, as I understand it, the only change to the 24-foot deep section on the left, was the removal of the gable vent. Because I see no gable vent on the 28-foot deep half of the house, there must have been a connection between the two attics. So now that the gable vent has been removed, how is the attic of the narrower section ventilated? No ridge or soffit venting were added. Is this what the home inspector is referring to?

In extending the front roof to cover the bay window as part of the main roof, the extension has a shallower pitch. I assume that nothing was done at the change in the roof pitch that is interfering with the air flow, including the area over the bay window having closed-cell spray foam. Otherwise, there is no effective ventilation. Hopefully, there are no other obstructions to the air flow between soffits and ridge.

You refer to pink baffles. Are they only at the rafter seats while the R-30 fiberglass is laid flat between the ceiling joists, or is it a cathedral ceiling? If the latter, the roof rafters must be hefty for such a small house if you were able to use R-30 and baffles between them. If the pink baffles are made of flimsy foam, the pressure of the expanding fiberglass may crush them, and if they do not vent the full width of the rafters, ventilation is restricted. I wonder if this is also what the home inspector is referring to.

Ventilation is one of the factors to a healthy attic, but the most important one is the tightness of the conditioned space to prevent convection of warm, moist air into the attic. Convection is what often results in mold and other problems.

You mention there is no evidence of mold or ice dams, but the finish photo you sent me shows no evidence that anyone is living in the house. It may take one or more winters in a house lived in full time before ice dams develop and more winters than that for mold to develop in an attic.

Q. We have a similar problem to the person whose garage door will not work when the sun reached the sensor. Our door does open using the button on the garage wall. The difference with our door versus what the issue was in your recent column is that our garage door does not get sun exposure. So what could the problem be?

A. I assume you mean the garage door does not respond to the clickers in your cars. If this is the problem, the clickers may need new batteries.

If that is not the issue, consider calling the garage door company that installed the doors, if you know who did, or call any garage door company handling your brand of door opener. They may be able to reprogram the clickers so they communicate with the door opener in the garage once again.

• Henri de Marne, a former remodeling contractor turned columnist and consultant, is the author of "About the House with Henri de Marne" (Upper Access Publishing). He continues to take questions from readers for this column and his website, www.henridemarne.com. Email questions to aboutthehouse@gmavt.net.