April, 2016
Insider Tips
Inspection News and Views from the American Society of Home Inspectors

Insider Tips for Smart Inspectors


Tip #16 Three-Way, Two-Way or One-Way Switch?

Home systems have some strange terminology. Why are the two light switches that control one light fixture called a three-way switch? You know–the kind with a switch at both the top and the bottom of the stairs. Sometimes it’s up/switch off and sometimes up/switch on.

The name relates to switching the power line back and forth and having an extra wire and connector. Electricians call this a three-way switch, and it takes a smart electrician to wire this properly.

You may not care about the details, but you should care about the switches and what they control. Here is the quick tip: You can identify the type of switch by looking at the marking on it.

Single-pole switches, with one switch controlling one light, are marked with an “on” and “off ” position.

A three-way switch has no marking because there is no consistent on or off position. The on-off can change depending on the position of the second three-way switch. Take a look at the switches in your home. You may be surprised with what you have overlooked.

Tip #17 Caulking the Wide-Open Spaces

So you filled that wide gap in the exterior trim with the best caulk you could buy and the next year it had pulled away from one surface, leaving a large gap. Or you tried to fill a wider gap and the caulk just fell in the hole. What went wrong? No backer rod.

Before professionals fill a large gap with caulk, they bridge the wide opening with a stiff foam backer rod. The backer rod is wide enough so friction holds it just below the gap’s surface. The rod supports the caulk applied in an hourglass shape with a height-to-width ratio of about 1:2.

Why? Caulk needs to expand and contract as surfaces move. The hourglass shape allows the caulk to bond to only two surfaces; the narrower section easily expands and contracts with movement. Caulk should never completely fill a space. It should never be applied to three sides or an unbridgeable wide gap or it will quickly fail. Caulk can’t expand and contract when it is pulled in three directions or when the cross section is too thick.

You will find backer rods in larger paint and hardware stores. It is sold in lengths like rope and it comes in various diameters. Choose a diameter that is wider than the gap to be filled and force the rod into place with a blunt tool or putty knife. H