With any project you estimate, everything you count or don’t count is relative to the project’s costs and how much profit your company will make. Calling a project “residential” doesn’t guarantee you will make money. Therefore, do not approach residential jobs casually.

Estimating residential work is not very different from estimating commercial work. You should apply the same takeoff methods, approach and counting disciplines; you should segregate your takeoff by systems, drawings, areas and, of course, bid form items. Analyze your labor and direct job impacts, handle your vendor quotes and prepare your bid proposal the same way you would any other project.

One primary difference is in the materials you use, which can also affect your labor hours. Residential projects typically carry a different specification for materials than most commercial projects. Although, typically, these items are less expensive, never assume they are cheap or easy to install just because the materials are specified as “residential.”

When is a box just a box?

Specifications are meant to be interpreted. Often, the engineer merely tells us the outlet boxes need to be stamped steel or plastic, made by this brand. Rarely do they give us specific part numbers. Now, the last I looked, there were about 20 different types of plastic boxes you could use on a residential project. They range in price from 35 cents to well over $10. At the bottom of the price range are simple, basic boxes with no special features. At the top are higher quality, adjustable boxes with built-in wire connectors and device brackets. The labor to install these boxes may not vary too much, but the adjustable boxes could require more labor during the trim phase as they may need to be, well, adjusted.

But let’s focus on the material cost. It’s a matter of simple multiplication. If there are a 100 boxes and your estimate carries a $2 box, that’s $200. If the specification calls for a $5 box, you have a $300 bust. Not so bad. But what if there are 500 boxes or 2,000, which could easily be the case on an apartment and condo project? Suddenly your $3 bust becomes a serious issue.

The boxes are one material item. If they are specified to a higher quality, it is likely other materials are, too. To achieve an accurate estimate, you must use materials that meet the specification and, hopefully, the same materials that will actually get used in the field by your company’s electricians.

Estimating myth No. 2368: residential lighting fixtures are faster to install

Here’s another place you can get yourself into a pinch: fixture labor. Knowing how to correctly labor lighting fixtures is critical. Never assume a downlight is a basic downlight, or a sconce is simple to install. Today’s modern homes can have very expensive, complex lighting fixtures—especially larger, custom homes. Fancy fixtures don’t always arrive at the job site assembled and may have decorative glass. Be aware of this and add special handling labor to those fixtures.

Since lighting fixtures are in practically every room of the house, if you don’t apply the correct amount of labor to them, you will lose money. Of course, apply too much and you could lose the bid. (Estimating is so fun!)

That’s a huge cable you’re pulling there!

I recently visited a friend’s nearly finished house. As I walked into one of the bedrooms, I noticed a huge orange cable hanging out of a wall outlet. This cable was at least -inch in diameter, if not larger than an inch. As I looked at it, I realized it was carrying a couple Category 6 data cables, a coax for CATV, a couple speaker wires and a couple small control cables. I somewhat jokingly asked, “What’s this for?” He replied, “Everything!”

I started thinking about this cable and how things are changing with residential work. It used to be just plastic boxes, Romex, telephone wire and coax. I thought about the time it takes to install, how much it must cost per foot, what size staples or straps you need to secure it, how big a hole to drill through the wood studs and fire-blocks, and about fire seal and what size conduit it would require, that is, if conduit were required.

Since I have mainly worked on commercial jobs most of my career, I have not had to think about (nor did I know about) this cable. If I had simply seen the catalog number on the plans, would I have realized how large it was? Would I have researched it and tried to find out? Would I have factored the labor for it correctly? Well, I think I would have, but what about you?

To be continued …

SHOOK is the president and chief estimator for his estimating company, TakeOff 16 Inc. He has worked in the electrical construction industry for more than 23 years. Reach him at 707.776.0800 and sfs@TakeOff16.com.