Q. We live in a Campanelli ranch with a slab basement. Our water stopped running last winter. Frozen pipes? We cannot see them. What do you suggest?
PENNY G. MCKENZIE, Lynnfield
A. This is a good opportunity to educate readers for later this year when the weather turns cold again. You can call in a plumber with a pipe-thawing machine, also known as a Hot-Shot kit. The machine can thaw water pipes up to 175 feet long quickly and effectively by using low-voltage, high-current electricity. It can thaw iron, polymer of vinyl chloride (PVC), cross-linked polyethylene (PEX), or copper pipes buried in the ground or concealed in walls.
Q. Our master bathroom is over our garage, which makes for a very cold room every winter. A pipe out there has frozen several times, so we had our contractor add insulation to the garage ceiling around the pipes. We still have the problem and have not been able to identify the pipe causing it.
Now we leave the water running in the two sinks and the shower when the temperature falls below 30 degrees. You have mentioned in previous columns that this does not really work.
You have recommended the installation of electric heat cables on vulnerable pipes. Can this be done inside a wall? Is that safe and up to code? We used to have heat cable on a roof that worked well in preventing ice dams. Is this similar?
WENDY & PETER
A. Electric pipe-freeze-protection cables, also referred to as heat-tracing cables, raise the temperature inside the pipe and can be used in a wide range of applications.
There are two kinds of pipe-freeze-protection cable: self-regulating and constant wattage. The constant-wattage cable is designed to maintain a higher temperature and uses more electricity than the self-regulated, which requires a thermostat and generally turns on when the surface of the pipe is 40 degrees.
I’ve installed self-regulating heat cables made by a company called Warmup. Self-regulating heat cable has a special conductive core between two internal bus wires. The heating cable will increase its wattage per lineal foot in response to the cold. Smart, right?
TIP: Make sure the self-regulating cable is installed on the bottom of the pipe. It is important to wrap the heat cable with pipe insulation. Pipe insulation greatly increases the cable’s efficiency and helps to prevent heat loss. Use aluminum-foil tape to cover and attach the heating cable to the pipe.
Installing a heat-tracing system is not only cheap insurance, but it is a proactive and cost-effective way to protect your investment.
Q. I live in a 1920s Cape with no attic and not much insulation under the roof, if any. One winter, I had ice dams with a bit of water coming in the kitchen (where the roof is almost flat). I immediately hired two guys to break up the ice dams, and I got through the rest of the winter with no more inside water. I did buy a roof rake and removed as much snow as I could throughout the winter. My roof was old and took it hard.
That summer I replaced my roof with regular shingles, not architectural ones. The roofer put 6 feet of ice and water shield under my roof. Do I still need to rake off the snow?
A. I’m concerned that the roofer put only 6 feet of ice and water shield on your “almost flat” roof. Are you positive? Flat and almost flat roofs should be covered with rubber, so I’m betting that you have at least a three-pitch roof, which is the minimum code will allow in asphalt-shingle installation.
Still the roofer should have completely covered your section of low-pitch roof and continued up the steeper part a minimum of 3 feet. I tell people all the time that ice and water shield is cheap insurance.
I can’t tell without looking at your home whether you’ll need to rake off the snow. If the roofer is reputable and competent, then I’m guessing this job was done right and you’ll be fine without doing so.
Rob Robillard is a general contractor, carpenter, editor of AConcordCarpenter.com, and principal of a carpentry and renovation business. Send your questions to email@example.com or tweet them to @globeaddress or @robertrobillard.