Call in a professional to take on cracked table

Q. We have a table from India. It has developed a crack one-eighth inch wide and 12 inches long on the top. I believe this is due to humidity changes. I'd like your recommendation as to how to fix it. The crack has been there for three years and has not gotten any bigger. Thanks.

A. The best solution is to take the table to professional furniture restorers.

You should call one of these companies to see if someone can come and look at your table and advise you on how to repair the crack. However, the table most likely will have to be taken into the shop.

Q. I have a house with a hip roof (5/12 pitch). Four years ago, I had the insulation in the attic improved and found out the soffit vents were never opened; they were put over solid boards.

When I needed a new roof, I had Airvent Edge vents (www.airvent.com) installed along the whole perimeter of the roof about three feet up from the eaves to provide intake ventilation. The roof has about 15 feet of ridge vent installed for exhaust. In the winter, I am getting moisture in the attic. Doing the calculations, the problem appears to be not enough exhaust area (see attached drawing and calculations).

I wanted to utilize passive vents near the ridge vent to provide more exhaust area. I was told that this will create a bypass - the same as gable vents and ridge vents. If I go to a power ventilator fan, I have been told various things to do about the ridge vent - leave it open, close it off because of the bypass effect.

What is the best solution? I have seen many instances with higher (steeper) pitched roofs where they use ridge vents plus static round or square vents. Are they able to do that because of greater distance between intake vents and exhaust vents? I would appreciate any help that you could give because I am getting conflicting statements.

A. The major cause of an attic's condensation is the convection of warm, moist air from the living spaces finding its way into the attic.

This can happen from a variety of small openings: cracks in ceiling and wall materials, separation of drywall tape, recessed or surface-mounted ceiling fixtures and fans, access panels (known as scuttle holes) or folding stairways to the attic, etc.

You didn't say when the new roofing was installed. Was it at the same time as the increase in the insulation or some years later? Was the ridge vent already in place, or was it first installed with the new roof? These are important answers to know in order to come up with an accurate diagnosis.

If you are sure the moisture in the attic is a recent event that developed since the insulation was increased, it may be due to the cooling of the attic. This would cause an increase in the relative humidity (RH) of the attic's ambient air, since colder air cannot support as many water molecules as warmer air. The previously warmer attic may have kept whatever small amount of moisture convected into the attic from condensing on rafters and sheathing. Large amounts of convection would not have been kept in check.

I do not believe the moisture problem is caused by the differential between air intake and exhaust. It is better to have a greater net free ventilation area (NFVA) intake than exhaust.

If the passive vents you are thinking of adding are just below the ridge vent, they should not create a bypass, but this would look very unattractive. A better solution would be to install Air Vent Inc.'s VenturVent Roll or RidgeVent 20 on the roof hips, starting at the peak and terminating 5 or 6 feet down. This should increase the exhaust without causing a bypass as long as you don't carry the hip vents too far down.

I would not recommend a power fan; they can have deleterious effects on heating and air conditioning of the living spaces.

But the first thing to do is to look for all possible convective paths. Sealing them would likely solve the moisture problem. If the problem turns out to be a major source of condensation, which should be controlled to avoid more serious problems over time, you may want to consider an infrared thermography/blowdoor test performed by an experienced practitioner. This will help detect all convective paths and make it easier to seal them.

Q. After finally getting someone to do a minor kitchen remodel, which was not very carefully done, I have now gotten the living room painted and am ready to hang pictures.

We did see how thick the plaster walls are (I think 1½ inches or more), and a contractor said they are the better type of plaster walls - the kind that won't bow or anything like that.

The house is a 1950s ranch. We never had plaster walls before, so I am afraid to mess them up and have gotten a couple different stories on how to hang pictures.

I purchased a stud finder, but it doesn't seem to work on these walls; we used the thick wall setting.

However, the one painting that weighs perhaps 20 pounds needs to be in the center of a short wall, so if there are studs, there might not be one in the center.

Should I be using something special? And I think we need to drill holes first, right? The person who framed the heavy painting said to use two hooks. She gave me heavy-grade picture hooks, but I'm not sure if it makes sense to use two as they'd have to be pretty close together.

I should mention that behind the wall we are starting with is the garage wall, which does have electrical wiring in it. The lines are not "inside" the wall, but are encased in metal tubes in the garage. There is only one outlet inside the house on that wall, and it is low to the floor. I'm on hold until I hear from you.

A. Here is an old trick for hanging pictures on plaster walls: Put two Scotch tape X's about two inches apart where you want to hang the picture. Place the heavy hooks against the tape with the point of the nail in the center of the X's, and drive the nails in gently while pushing hard on the hooks to prevent the flaking off the top coat of the plaster.

The person who framed the picture was right: two hooks should be used, and they should be on exactly the same level.

Q. I have questions about some concrete work that was just done. You've probably answered these questions before, so please bear with me.

I had a new concrete walkway poured in the beginning of May. I noticed the concrete was starting to crack in the contraction/control joints. I believe this cracking is normal. These cracks seem minor now. In our area, the weather can get very cold with the snow and ice. I'm afraid with the freeze-thaw cycles in our area, these cracks will become bigger in time. Should I caulk these cracks?

Also, when should I seal the new concrete? I was told by other people that the fall would be a good time to do this. Would you have any recommendations for a penetrating concrete sealing product?

A. Control joints are there to control the normal cracking of any concrete work. It is usually not necessary to fill them with anything. But if you choose to fill the cracks, you could use the right size backer rod and carefully press it in the joints with a wooden stick, without breaking its fragile skin. Push it in to a depth not to exceed the width of the cracks. The purpose of the backer rod is to keep the caulking bead no deeper than the width of the crack and to allow the caulking to stick only to the opposite sides of the crack. It should not stick to the bottom of the crack or any other material on the back of the caulking bead.

Follow this with a polyurethane caulking compound, which you will probably have to buy in construction specialty stores. You are unlikely to find polyurethane caulking in hardware stores (they usually only carry silicone, latex and butyl compounds), but you may be able to find it in Home Depot (where I found Sika brand polyurethane), Lowe's or other big-box stores.

There are two kinds of concrete sealers, and you are wise to select a penetrating sealer. Before buying the sealer, spray water on the concrete. If it is absorbed into the concrete, you can use a penetrating sealer, which is a one-time application.

But if the water forms beads, the sealer is unlikely to penetrate the concrete. In this case, you may want to consider a topical sealer, which will need to be reapplied every year or two.

You should be able to buy sealers in construction specialty stores, building-supply stores, some hardware stores or online.

• Henri de Marne was a remodeling contractor in Washington, D.C., for many years, and is now a consultant. His book, "About the House," is available at www.upperaccess.com. His website is www.henridemarne.com. Email questions to henridemarne@gmavt.net, or mail First Aid for the Ailing House, Universal Uclick, 1130 Walnut St., Kansas City, MO 64106.

© 2015, United Feature Syndicate Inc.