Value of waterproofing solutions depends on customer

Q. We live in the so-called "five sisters" neighborhood in the south end of Burlington, Vt. Nice area, but apparently prone to wet basements. I took your advice and changed the grade on the east and west sides of our house. (The other ends are protected from surface water by being under porches.) That intervention was successful on the west, or downhill, side of the house, but not on the uphill side.

The water enters at the seam where the walls meet the floor, and as the ground outside gets wetter and wetter, water bubbles up through holes and cracks in the fairly thin 80-year-old concrete floor. We had good-quality rain gutters installed all around last fall, hoping to reduce the amount of water falling near the house. That may well have helped, but not enough, as the basement flooded twice this spring.

An added problem is associated with a new bulkhead that was built the year before last. It involved digging a big hole that extended about 8 feet into the back yard, into which the mason poured a slab floor and built walls from split-face (I think they are called) concrete blocks.

The bulkhead leaks extensively right through the concrete blocks and from the seam where the floor and the walls meet. I estimate that the bulkhead leaks now provide about 60 percent of the basement flooding. Obviously, our mason was not especially competent at this sort of thing, but he was a nice fellow, and it was my mistake for hiring him in the first place. I accept that the problem is mine.

I've requested and received estimates from two basement-drying companies. Both companies deal with wet basements by jack-hammering trenches along the offending walls and also out farther on the floor. They place thick, plastic-covered culverts with side holes on top of crushed rocks and cover these channels with concrete. The culverts empty into a plastic bucket that contains a sump pump. This work is quite expensive.

Do you think there is any way to significantly reduce the water that migrates through the walls into the bulkhead? Is there anything else we can do to prevent water from coming up from the ground into the basement? Do you have an opinion about the efficacy of the strategies employed by these basement-drying companies?

Via e-mail

A. It would have helped if the mason had waterproofed the bulkhead's blocks from the outside. I do not recommend that you waterproof the blocks from inside, although it would help your problem. The blocks would fill with water over time, and when the ground freezes, the blocks may crack, making matters worse. Is the grade around the bulkhead sloping away, as you have done on the west and east side of the house?

It does sound as if you have an underground water problem. The proposals you have received from the two waterproofing contractors should work. I have built this system on a few houses when surface grading did not solve the problem during my construction days in the Washington, D.C. area. The question is whether it is worth it to you, considering the expense. You should investigate their warranty thoroughly to make sure that, if their work does not completely solve the leakage, they will work on it at no additional cost to you until they stop it.

Q. Due to excessive water content during installation, my 12 year-old basement and garage floors are soft and they spall easily. There are no moisture problems now. Can you recommend a hardener that might help to keep things from getting too bad?

Hampton, N.J.

A. If by "spalling" you really mean "dusting," a hardener may help. If the concrete is spalling, you need different treatments. Assuming the surfaces are dusting (since you say they are soft), here are several hardeners you can try, but be sure you follow the manufacturer's instructions: sodium silicate, magnesium fluorosilicate, metallic zinc, cement paints, latex formulations, epoxy coatings.

Q. I live in a ranch-style house. Two years ago, I had a new felt tile roof installed together with some of the underlying wood sheeting because some of the wood had rotted. Insulation is in the ceiling between the rafter. There is no insulation to the peak of the roof and the insulation stops about a foot from the eves. I find now on the front inside of the roof in the attic mold is appearing. I do have breather vents on each end of the gables, a ridge vent, and the ceiling of the attic is insulated.

Via e-mail

A. I am somewhat confused, unless you used the wrong terms for the building components of your attic. Does the insulation run between the rafters (the sloping, framing members that make up the roof) to a certain height and then across the ceiling between collar ties? Or does it run between the rafters all the way to the peak of the roof? In the latter case, it seems as if the gable vents would be below the insulation and the ridge vent above. But you may mean that the insulation is between the joists of the ceilings below the attic, in which case the insulation is between the attic's floor joists. (They are one and the same.)

Ridge vents are ineffective if they are not in combination with soffit vents of equal or greater net free ventilation area (NFVA.) Since you are did not mention soffit vents, I assume there are none. In this case, even though gable and ridge vents are not compatible, your gable vents are helping. Without them, the ridge vent would be useless.

Because the insulation stops about 1 foot from the eaves, there is considerable heat loss at the joint of the ceilings and walls below. Since you notice mold, it means that there is also moisture convecting from the rooms below and that the attic ventilation is not effective at the eaves. (Only soffit venting in combination with ridge venting would do that.) When the warm, moist air comes in contact with the cold roof sheathing, condensation occurs and mold develops. The insulation should be carried all the way to the outside edge of the wall plates, and any cracks that allows moist air to convect from the rooms below into the attic need to be sealed. But unless you install continuous soffit venting in the middle of an overhang and close the gable vents, the situation may not improve materially. You may need to get an experienced weatherization specialist to help you with that one.

Q. In a back issue of the Star Ledger, your column mentions a product that may help control pigeons landing on my roof. Please repeat the name of the product and where I may purchase it.

New Jersey

A. You may be referring to BirdXPeller PRO (Programmable Species-Specific) Bird Repeller ($239.) It can be programmed for whatever bird species is a nuisance. Bird-X can be reached by calling (800) 662-5021 or by e-mail at sales@bird-x.com. They are located at 300 N. Elizabeth St., Chicago, IL 60607.