Home repair: Reflective shields prevent radiator heat loss
Q. My house is two-by-four frame construction with solid-brick outside (brick with no holes in it when cast). So from the inside of the room, there is at least one inch of plaster on lath nailed to a two-by-four stud with Homasote board on the exterior side, followed by about a one-inch air gap and then the brick. As the radiators sit now (inside the wall), there is a reflective shield on the exterior side of the radiator. Once I move the radiators fully into the room, insulate the wall behind them, and leave a two-inch air gap between the interior finish of the wall and the radiator, are you suggesting that a reflective shield be placed on that interior wall? Not a bad idea!
A. Yes, why not? Can you reuse the ones behind the radiators now? What material are they made of? Copper would be the most attractive but also the most expensive if you have to get new ones. Reflective shields will prevent radiated heat loss through the exterior walls while increasing the radiation toward the inside space. It is best to have a small air space between the interior finish and the shields to eliminate conductive losses. You can obtain that air space with short pieces of plastic tubing — a half-inch will suffice. I hope that the 2-inch-by-4-inch walls are insulated.
Q. In a recent column, you stated that Sikaflex-1a polyurethane caulking needs a week to fully cure or it will turn a dirty yellow/pink. Because I don’t care about the color, how long would it need to stay dry to cure well enough to seal? I’ll settle for discoloration and tough adhesion.
A. Forty-eight hours should be sufficient.
Q. Attached are three photos of ice dams building up on my roof. Photo 001 is the wood-stove chimney. I have not experienced any roof leaks there since I had diverters put up, but there is about eight inches of ice buildup, mostly on the northwest side. Photos 006 and 007 show the oil-furnace chimney, on the south side of the house. I have been having leaking problems there. As you can see, there is a lot of ice buildup and icicles backing up into the soffit and vents. It’s coming down through the partitions to the kitchen, downstairs closet and basement. There is a lot of ice built up and lots of icicles coming off the west side of the first-floor roof, too. I do have gutters all over the roof.
My house is a 1975 tri-level home. I’m only guessing that 3-1/2-inch R-11 insulation was used in the attic, as that is what is in the basement. In 2001, we had insulation blown into all the attic space — both levels. I don’t know how much was put in, but the contractor assured me that it should solve the problem of ice buildup. You suggested that the homeowner have an infrared and blower-door energy audit done. Who do I contact to have this done? Do you have suggestions as to a solution?
A. Heavy levels of insulation do not alone stop the formation of ice dams. The biggest source of heat loss into attics is convection. Warm, moist air leaks into attics through access panels, folding stairways, can lights, bathroom and kitchen fans, separation of drywall tape, electrical switch and receptacle boxes, and any other hidden holes in walls through which wires and pipes run. These must be sealed or done away with to stop the flow of warm air that melts the snowpack. A blow-door test and infrared thermography will identify these convective paths and point out what needs to be corrected. Call Efficiency Vermont, (888) 921-5990, for the names of contractors certified in this technology and remediation.
Q. I have read a few of your case studies and other online sources that point back to your expertise. I was wondering if I could trouble you with another case. I purchased my current house in northern New Jersey just over a year ago. It is one of many identical ranch houses in the neighborhood with cathedral ceilings built in the 1960s. What caught my attention: Icicles were hanging from underneath the soffit in the cold fall/early winter without any precipitation. And large icicles were hanging around the kitchen area. I do remember a softer feel in walking the roof in the summer, also above the kitchen. From my research, I understand that this type of non-vented roof is called a “hot roof” and could be dangerous.
How did the roof last as long as it did? Am I the only one in the neighborhood who has this problem? How do I fix it (on a budget)? I know the costliest method would be to remove the existing roof and redo it correctly with venting, but are there any other alternatives?
A. The icicles are caused by severe condensation on the roof sheathing running down and coming out through the soffits. The cathedral ceiling is probably insulated with fiberglass and, if the ceiling is finished with wood, there is a lot of convection through the joints between the boards. The longevity of the roof is probably due to its plywood sheathing, which was the material of choice in the 1960s. Of concern is the condition of the rafters, which may have developed worrisome rot and are weakened. It is important to determine the extent of the damages by opening a small section of the roof or ceiling below. Whatever is found will determine what needs to be done; and there are several choices. Unfortunately, whichever fix you choose will entail a considerable expense. Once you have ascertained the damages, write again and I’ll try to run through the options with you.
Q. I am a longtime reader of your column and a 73-year-old architect. Your advice to readers is well respected and appreciated. But your advice to the reader who has a nine-room brick house leaves me wondering: Why would you give advice to close up the openings in the sidewalls of the attic? These openings were most likely there for natural attic ventilation and may be the only ones in the attic. The purpose would be to ventilate the attic in both summer and winter. Therefore, they should not be closed in the winter, because their purpose is also to let water vapor that escapes through the ceiling (with or without vapor barrier) vent out to the atmosphere. There was no mention of eave or ridge vents in the reader’s inquiry. And if these wall openings are the only openings in the attic, condensation will build up on the underside of the sheathing and rafters, then drip down on the ceilings below. Needless to say, this would create an environment for the growth of mildew, mold and damage to the building.
There is also a second reader’s question about having installed a ventless natural gas heater in the garage. It is extremely dangerous to have a gas heater in a garage, where it could cause an explosion if the auto leaked any gas or fumes. I would have advised him to shut the heater off and replace it with a unit that receives combustion air from the exterior atmosphere and is a sealed unit designed for garages and vented through the outside wall. I hope you can review your advice and give the readers a clarification on these matters.
A. Your e-mail got my attention, and I looked back at the question from the Pennsylvania reader. I deduced from his question that he has access holes in knee walls of a finished attic room into a crawlspace, which would cause the heat loss he was concerned about. I located my personal reply to his letter and called him right away. You are correct; the holes are louvered and screened gable openings, and they should be left open. Fortunately, he hadn’t done anything about it yet but was getting ready to have the work done. You read his question correctly, and I didn’t. As to the ventless gas heater in the garage, I thought that my answer pointing out the dangers of unvented appliances in a confined space was enough of a warning. I didn’t think of the potential for an explosion because modern cars have such a tightly sealed filler caps. But you are right again; I should have pointed that out as well. Thank you for your valuable input.
Q. My daughter bought a house that has had some problems. The latest is this: A bathroom in the master-bedroom suite has a radiant heating floor and a big tub. During late autumn, we realized that this bathroom is constructed on posts sunk into the ground, and the pipes are exposed on the underside of the floor. We can see them if we go outside and look up under the house. The wash basin, toilet and shower pipes have been OK through the winter, but the pipes going to the tub have frozen. We have hiked up the heat and are hoping for the best, but we need to fix this problem when the snow goes. Should we fill that area under the house with insulation? Like a spray? Or what other options would come to mind? Thank you so much for any ideas that you might have.
A. Strange that someone would leave pipes so exposed in areas of freezing weather. The easiest fix, assuming that the area under the bathroom is open, is to enclose it with an insulated skirt, much like what is done under mobile homes. An insulated access panel should be provided for periodical inspections. Be sure to cover any bare soil with 6-mil plastic to control soil moisture.
DEAR READERS: I recently attended a two-day conference presented by Efficiency Vermont titled “Better Buildings by Design” that focused on improving energy efficiency of both residential and commercial buildings. This conference is an annual affair dating back several years, and each year, the workshops are instructive and presented by speakers of many disciplines from all over the world. These speakers bring us exciting perspectives into the continuing search for ways to save energy while improving our buildings and our impact on our planet.
In 1999, an act of the Vermont legislature created Efficiency Vermont to help Vermonters reduce their energy costs, and protect the environment. The law took effect in 2000, substituting a uniform and comprehensive set of services for those previously provided by most Vermont electric utilities. These services are paid for by an energy-efficiency charge on ratepayers’ electric bills. Efficiency Vermont certifies contractors to provide the audits and the services needed to improve the energy efficiency of residential, commercial and industrial buildings. The program has been so successful that other states have taken notice and have contacted Efficiency Vermont to help them set up similar services.
I have attended the majority of these conferences over many years and always come back feeling more energized and able to perform my work, knowing that I have updated my knowledge of these important issues. Although these workshops are aimed at builders, contractors, architects, engineers and other building professionals, they are worthwhile for the public, so that homeowners can understand the complicated and interwoven pieces of the ever-developing energy we all use, as we are all responsible for using it.
Ÿ 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.
$PHOTOCREDIT_ON$© 2011, United Feature Syndicate Inc.$PHOTOCREDIT_OFF$