Homeowners Clinic Expert Q & A - May 2005

Professional Engineer Norman Becker solves readers' dilemmas ranging from remodel electrical boxes to the interference between a furnace and a dryer vent.


I bought new light fixtures for my bathroom, but when I removed one of the old fixtures I found there was no junction box. There is no stud near where I need to place the junction box I would like to install. Please help.



You should be able to install the light fixtures using an old-work electrical box (also known as a remodel box). It's sold at hardware stores, home centers and electrical supply stores, and is available in any number of rectangular and round configurations. Your choice depends on whether you're installing a switch, an outlet receptacle, a group of switches or a ceiling light. We show a rectangular box that can be used to install a switch, a receptacle or a fixture in a wall. (For more information, see the National Electrical Code.)

Unlike a new-work box that is attached to wall studs (and is installed when the house is built), an old-work box is installed after the house is built. It attaches directly to the drywall, provided the drywall is in good enough condition so that it can support the box and electrical equipment attached to it.

To install the box shown above, hold it so its face is against the wall and trace the outline of the box body with a pencil. (Don't trace around the box flanges.) Then cut around the line with a drywall saw. After removing the waste piece of drywall, pull the electrical wires into the box and set the box into the hole. Then tighten its two screws. Doing this pulls the box's clamps against the back of the drywall, fastening the box tightly in place between its flanges and the clamps. Next, make the light's electrical connections, install the light fixture's mounting strap to the box and mount the fixture to the strap.

The box shown is typically used for installing switches, and outlet receptacles, but it can support a wall fixture up to 6 pounds, according to the manufacturer. The box has a small opening but its extended depth gives it a large volume (20 cu. in.). This allows plenty of room for cable and electrical connections, and makes it especially handy for electrical installations in a tight spot.

When installing this or any other junction box, follow the manufacturer's instructions and make sure that the electrical power to the circuit is turned off. The work that you do must conform to current electrical codes.

Before starting, check with your local building department. Some municipalities allow homeowners to make minor electrical modifications, but others require that an electrician do the work.

For more information on old-work junction boxes, visit Carlon's Web site at www.carlon.com.


How do I figure out the square footage of my roof to determine the number of squares of roofing I will need?



Roof area can be measured from the ground or from the roof itself. Direct measurement is the simplest and most accurate method. A roof area generally is made up of rectangles and triangles. Odd shapes such as parallelograms and trapezoids can be subdivided into rectangles and triangles. The area of a rectangle is length x width, and the area of a triangle is one-half base x height.

However, to take a direct measurement of the roof requires you to walk on it and that can be dangerous, especially if its slope is steep. If you go up on the roof, be extremely careful. Many things can cause you to lose your footing: loose shingle granules, shingles that tear free when you step on them, or debris such as acorns and pine cones that can roll under your feet.

The difficulty of calculating the roof area from the ground is that you must determine the slope or pitch of the roof so that you can calculate its length. The problem is further complicated if it is a roof with dormer projections and intersecting planes. Still, you probably can make a rough estimate.

A third option is to stand a ladder against the side of the house and feed the blade of a 25-ft.-long tape measure up the roof (the horizontal length can be measured from the ground). This might work on a small roof. On a large roof, it's likely that the tip of the tape will snag on a shingle the farther it is extended.

Once you know the area of the roof, you can calculate the number of roof squares needed.

For readers unfamiliar with the term, a roof square equals 100 sq. ft. You divide the roof area by 100 to determine the number of squares needed. Then, ask your roofing supplier for the number of shingle bundles needed per square.

SIMPLICITY LEGACY XL 4X4 This tractor is a recent addition to the new and growing field of subcompact garden tractors. These machines share the compact size of a garden tractor and many of the high-end capabilities of a full-size compact utility tractor. The model we tested had 4wd and a 60-in.-wide midmount mowing deck. We ran the machine for a full mowing season and were impressed on nearly every front.

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Tractor Specs
1280 lb.
51 in.
Tractor Width
44 3/4 in.
81 in.
Mower Width
60 in.
0-9 mph

It cut 6-in. dry grass uniformly and discharged grass in a wide, even pattern. For a torture test, we cut an old hayfield, where the grass was about 16 in. high. The Legacy cut most of it in one pass without complaint. A second pass finished the job.

The adjustable seat was very comfortable, the controls and gauges were well designed and logically placed. The fit and finish, and service accessibility were superb, and the tractor was fairly quiet while mowing (89 dBA). The only fault we found was with the cruise control, which performed well only on flat ground. The tractor sells for $9375 and the 60-in. mowing deck costs $1630 at Simplicity dealers. Many other attachments are available. For more information, go to www.simplicitymfg.com.--Steve Willson


Would it be advantageous to have a battery-operated sump pump instead of the normal electric-powered pump? I have both. The battery unit is for emergency use when power fails. Why not go with the battery full time?



Batteries eventually run down, even when they are not powering an appliance. Homeowners should check their sump pump's battery periodically, but most fail to do so. You certainly don't want to find out that the battery has run down when the water level in the sump is rising.

Even when the battery-operated sump pump is used only for emergency use, you should check its battery regularly and make sure it's charged. The best way to test it is to pour water into the sump and see whether the pump can remove it.


My girlfriend owns a home built in 1893. All of the switches are the pushbutton type. I have had no luck finding replacements for them. I need both single-pole and three-way switches. If you could find this information for me, I would really appreciate it.



You can buy the pushbutton switches from Classic Accents. Call the company at 800-245-7742 for a product catalog or visit www.classicaccents.net. The single-pole switch HD1 costs about $13 and the three-way switch HD3 costs about $16. Shipping varies depending on the order size, but probably will be an additional $6 to $10.

Pushbutton switches were used in a majority of American homes in the first half of the 20th century. Classic Accents' switches have been designed to work with existing and new wiring, and have been duplicated right down to the synthetic mother-of-pearl inlay on the buttons.

NO MATTER HOW many woodworking clamps you own, sometimes none of them is right for the job--especially when small parts are involved. One solution is to use masking tape. Prepare the parts so that they fit together without forcing them, then apply a light coating of glue to both surfaces. Join the parts and apply a strip of masking tape over the joint, stretching it to apply pressure. With a long joint, use strips of tape every 2 or 3 in. Once the glue cures, peel away the tape and gently pare off any squeeze-out with a sharp chisel.--Neal Barrett


A contractor installed the air inlet and exhaust vents for my new high-efficiency furnace immediately above the dryer vent, which he then removed. He advised me to vent the dryer elsewhere. I want to vent the dryer out the same wall about 8 to 10 ft. away from the furnace's air inlet. Is this far enough away to avoid pulling in exhaust fumes from the furnace?



Readers unfamiliar with this issue should be aware that the slight depressurization that exists in a house can cause exhaust to enter a house even by such unlikely means as a dryer vent.

Although you didn't mention which high-efficiency furnace you have, the 8- to 10-ft. clearance that you suggest probably will work. One set of instructions I looked at for a high-efficiency furnace required 6 ft. between the air inlet/exhaust and a dryer vent. You should check the installation instructions for your particular furnace.

Check your local building codes for required clearance. The codes take precedence over manufacturer's instructions, although in many cases they may be the same.

MY KIDS, Peter and Carolyne, love this playhouse that I made based on plans for a shed in POPULAR MECHANICS (go to www.popularmechanics.com/groundskeeper). The playhouse has two floors, a spiral staircase, windows, a deck, a double door, and a split Dutch door with a serving ledge that the kids use to play post office. The footprint is 7 x 8 ft., so I used 2 x 3s and made most of the studs 12 in. on center to get more floor space. The doors are made of glued 1 x 6 pine with "Z" crossbracing. The carpeted second floor has a couch and a chair. The kids play pirate ship on the deck. The vinyl siding and the shingles match my house's. It took me about a month (and $1500) to build. It's the playhouse I always wanted.--Jeffrey Strobel, Wyoming, MN

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