Seal off air leaks in attic for better insulation

Q. We have a 100-year-old house with no soffits. We have a new roof with new sheathing and 30-year shingles. We installed heavy-gauge metal about 18 inches up from edge of roof; weather shield was used liberally in valleys and edges. And they put the spongelike ridge material on, for air-venting help. The only other venting is a couple of small square vents on the ends of the house near the peaks, but not nearly enough for proper venting. We have about 12 to 16 inches of blown-in insulation in the attic. We still get quite a bit of ice buildup and are considering either more blown-in or spray-foam insulation on the underside of the roof itself.A. Since the roofers installed an ice-and-water protective membrane at the eaves, there was no need to install an unsightly metal ice belt as well. And with the installation of the new roof, that would have been the time to use a special eaves drip edging that provides soffit venting in houses without overhangs. I would not recommend spraying foam between the rafters onto the roof deck; insulation belongs against the heated areas. Before you add more cellulose, make sure that there aren't convective paths allowing warm, moist air from the living quarters to flow into the attic, raising its temperature enough to cause the snow pack to melt and turn into ice at the eaves. These paths are the worst offenders, which can be the entrance to an attic stairway or its access panel, recessed light fixtures, wall switches and receptacles - if the wires to and from come or go through the attic, plumbing vent pipes, joints between different materials that are not completely sealed, etc. Once you have made sure all these potential sources of warm-air leakage into the attic are sealed off, you may find that you have enough insulation and need not increase the existing ventilation, even though it is not very effective. If it turns out otherwise, you may add more blown-in insulation.Our 1967 brick ranch originally had 2 inches of Johns Manville kraft-faced fiberglass in the walls and in the attic. I find that very few people have heard of the 2-inch type, but it is printed right on the kraft facing. In 1973, I added another 31/2 inches of unfaced. Two room additions in 1980 and 1993 have 6-inches of kraft-faced. The attic floor consists of 2-by-6 framing, so the insulation comes to the top of the joists. The joists' tops are exposed, but about two-thirds of the attic is covered with 7/16 OSB flooring. Textbook recommendations say to pile on the fiberglass to achieve anywhere from R-49 to R-60 levels. This would effectively eliminate the flooring, unless I take the radical step of adding to the framing. I've thought about putting a layer of rigid foam, like Owens Corning FOAMULAR, which I've been told is not a vapor barrier, on top of the OSB and adding another layer of OSB. The 2-inch FOAMULAR is rated R-10. I've thought about taking up the older insulation and adding newer, higher quality stuff like Johns Manville R-21, which is 51/2 inches. I'm waiting to hear from a company that installs open-celled foam, which I understand is very expensive. We are pretty well air-sealed. All windows and doors have been replaced, and we have two, nearly new high-efficiency furnaces/AC units. A. Two-inch thick fiberglass is what we used to refer to as "masonry insulation" in the old days. It was not commonly used after the 1950s. It is very unusual to find this little insulation in attics built in the late '60s. I assume that you did not add insulation to the walls, as this would have required opening them up. However, you can increase the wall insulation by having cellulose blown in by an experienced contractor, who will be sure not to exceed the density of the dense-pack, which could blow the wall finish off. This will effectively squeeze the 2-inch thick fiberglass and improve the R-factor of the walls from R-7 to R-12 or so. But is it worth the cost? The recommendation to insulate attics to R-49 or above is not very realistic in most existing attics, and not easy to accomplish where there is flooring and storage. You certainly can add unfaced fiberglass in the unfloored areas to whatever level you wish, but it doesn't make sense to remove what you have to replace it with new fiberglass with only an improvement of R-2. Keep in mind the law of diminishing returns; the first few inches are the most effective insulation. To increase the insulation in the part of the attic that is floored will require a lot of work and expense for little gain. The two-thirds of the floor covered with OSB represents a very small part of the total square footage; the walls are the weak part of your total envelope.I have 21-year-old Andersen High-Performance double-hung windows. The windows allow quite a bit of air leakage between the panels, and several cords are broken. Should I replace the windows with more energy-efficient models or have the windows repaired? Are the newer windows significantly more energy efficient?A. Andersen windows installed in the 1990s should not be performing that poorly. Would air leakage occur because the sash locks are either not used or need adjusting? The cords can certainly be replaced. Call Andersen's main office in Bayport, Minn., (800) 426-4261, and ask them for the name of the nearest repair service.There is a large crack below the bottom of my front porch step, which I put a "concrete patch" on in the past only to find it cracked into pieces several months later. Can you please tell me how I should properly repair this crack to avoid having any problems in the future?A. From the photos you sent, it is obvious that it is a very difficult crack to fill. The concrete walk stops at the base of the last step, so there is a void below the steps. Using a flashlight, check to see how deep this void is; it may need to be filled with a cement slurry that you will need to push in with a stick until it is completely filled. Once it has cured, try again to fill the crack with a product like Thorocrete. There could also be movement during the winter that may break whatever repair you make, unless you can successfully fill the void and not tie the repair to the walk.The concrete floor in the workshop was painted over 25 years ago and is showing its natural concrete (color) throughout this area. I would like an easy (if any) solution to repainting or improving the looks of it. I am somewhat fearful of using strong chemicals because the furnace is located in that same area. I sweep this floor and sandlike particles come up where there is original concrete flooring. The rugs were put down to keep these particles from becoming airborne and to eliminate tracking through the house. A. The photos you sent show a difficult problem. This is why I do not generally recommend painting concrete basement floors; it is best to stain them if plain, bare concrete is not acceptable. Unfortunately, you would have to remove all the old paint to get down to the original concrete before you can attempt to stain the floor. But you seem to have another problem. You mention that when you sweep, sandlike particles come up; this is known as "dusting," which is caused by one or more of several mistakes made during the pouring or finishing of the slab. This may be why someone painted the floor years ago in order to attempt to control the dusting. The problem with that approach is that the paint could not bond satisfactorily to such a weak surface. Unless you can live with what you have, the best solution is to have a concrete contractor wet-grind the surface and apply a top bonding coat. It will be expensive, but there are less pricey alternatives, such as carpeting or the installation of vinyl tiles.I have a 250-year-old house that has a foundation made of stone with no mortar. Occasionally, I get assorted critters coming through the various cracks and holes that have formed between the stones along with moisture. What options do I have to seal the walls? A. If the joints between the stones are clean and deep enough, you can work in some mortar. They probably have some soil or sand in them, so you may have to brush them clean so the mortar mix can adhere to the stones. You must be prepared for an unsuccessful repair, as it is difficult to do satisfactorily. Foaming the joints is another option. bull; Henri de Marne was a remodeling contractor in Washington, D.C., for many years, and is now a consultant. Write to him in care of the Daily Herald, P.O. Box 280, Arlington Heights, IL 60006, or via e-mail at henridemarne@gmavt.net.#169; 2010, United Feature Syndicate Inc.