Mastic or duct tape for a dryer's vent line?

Posted: November 25, 2005

Question: I just read your advice on duct tape and mastic. Should I not use duct tape to join the pieces of my clothes dryer's vent line? Is mastic the thing to use for that also?

Answer: I think you'd be better off using duct tape - the kind for sealing heating, ventilation and air-conditioning ducts, not the cloth-backed variety - rather than mastic, which is better for sealing duct seams.

Duct tape is flexible and tears off the roll easily. I prefer the tape to mastic because, though many basement laundry rooms aren't exactly pretty, mastic looks ugly.

Q: I have hot-water heat that is gravity-fed. The water is pumped up to the attic and then is gravity-fed to the radiators in the house. I have the main pipe well insulated, but have purposely left the branches uninsulated.

My reason is that keeping the attic a little warm would keep the upstairs warmer, and would also make the shingles last longer. Is my thinking wrong? Am I wasting fuel? Should I insulate the branches?

A: The attic should be insulated in a way that keeps it cold and the floor below it warm. Escaping heat will cause any snow that falls on the roof to melt, and can create ice dams. Insulate those pipes so the heat stays in them and remains at a high temperature when it drops back into the radiators.

Oh, and having the attic warm rather than cold will make the shingles deteriorate more quickly.

Q: What are the best ways to baby-proof a house?

A: If you want to know how easy it is for a baby to get into things, get down on your hands and knees and crawl around. What you can reach will surprise you. One of the first things I did after my second son arrived and started wandering was to add balusters to the deck railings to make it impossible for him to get his head between them. There should be no more than four inches between balusters.

Here are some other precautions to take:

Store hazardous items out of harm's way: knives, medicines, household cleaners, even shaving cream and deodorant, all of which can hurt the baby.

Keep small appliances unplugged and out of reach, hide plastic-wrap products on high shelves, and cover garbage cans with tight lids.

Limit access to the garage or basement, either with gates that fit snugly into areas at the base of the stairways or by making sure the doors to those areas remain closed and locked. Stay away from accordion-type wooden gates (another place a little head might fit through); use plastic gates with mesh panels.

Plastic insulator caps that plug directly into electrical receptacles keep little fingers out of sockets. But it would be better if you made sure all the receptacles were in working order and replaced as many as possible with ground-fault circuit interrupters, which cut the power immediately on contact with moisture.

Under-the-counter spring locks prevent cabinet doors from opening fully. Drawers are tougher to deal with, so it is best to keep dangerous items out of lower ones.

Q: What is mercaptan?

A: That's the rotten-egg smell added to odorless propane or natural gas to make you aware of a leak.

If you smell it, there's a problem somewhere. Leave your house quickly and call the local gas company.

Q: What kind of clear protective finish can I use to coat my outdoor steps? They are made of mahogany and were coated with some kind of clear finish when installed. It didn't wear well. After one season, the finish was worn off.

What would you recommend that would be durable and wouldn't change the color of the wood?

A: Marine varnish would be my best guess, but remember: Nothing lasts forever, and you will have to redo the work periodically, just like a wood deck or a boat.

Q: Is it possible to paint white vinyl inside windows? I have one, and I would like it to be brown, with a wood look.

A: Although some vinyl windows are paintable, most aren't. Check with the window manufacturer.

Have questions for Alan J. Heavens? E-mail him at or write to him at The Inquirer, Box 8263, Philadelphia 19101.

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