The Big Three Contractors and their natural order


March 26, 2000|By Karol V. Menzie and Ron Nodine

THE CONCEPT of a tabula rasa -- a blank slate -- is usually associated with philosophy or psychology, but it's a useful concept in thinking about dwelling places and building or renovating them.

When you buy a new house, you're getting a partial blank slate; you choose from models offered by a particular builder, and from a series of finishes the company offers. You can get a more blank slate by having a home designed by an architect, but your site will always affect the design.

When you buy an old house, the slate has been scribbled on and erased many times. You can erase it, or erase some of it, but you're going to be stuck with some historical baggage.

There's no place this is more prevalent -- or more important -- than in determining how and where the new systems will be installed.

There is a standard sequence in the industry for how this should be done. Of what Ron calls the Big Three Contractors -- heating-ventilating-air-conditioning, plumbing, and electrical -- the first one to get to work is the HVAC contractor.

There two reasons for this: One is because ductwork is the hardest thing to conform to a given space and, because of that, it is the first thing that has to be considered in the planning stage.

Where will the air handler (furnace) and condenser be located? How will the ductwork be distributed to allow air to flow to the places it's needed throughout the house? Typically you would want your supply registers near exterior walls and particularly near windows. The return air vent should be centrally located in the house and the thermostat should be near the return air vent.

You will probably need chases (enclosed vertical boxes) and bulkheads (enclosed horizontal boxes) to conceal the ductwork. In most houses you will have to run a trunk line to the basement equipment down at least one side, then the smaller supply lines can cross the room in the ceiling between the joists. How these lines are placed can have a significant influence on the design of the space. For example, if you have a chase at one end of a wall, you may want to put an identical fake chase on the other end and put an entertainment center and/or bookshelves between them, to disguise the real chase.

Once the ducts are in place, the next step is plumbing.

While water lines can run almost anywhere, drain lines, like ducts, may be difficult to configure, partly due to building codes. The hardest thing to place will be the 3- and 4-inch sewer pipes and vents. All open drains must have traps in them to prevent sewer gas from entering the dwelling, and all pipes must drop at least a quarter inch per foot run. Allowing for the drop, and maybe for the trap, will sometimes require a lowered ceiling or a bulkhead in the room below.

The plumbing and ductwork must be coordinated with each other before work is begun to avoid problems. Otherwise the duct man will, without fail, install his duct right where the sewer line has to go or the plumber will put his sewer line where the duct needs to be.

Electricians have the most flexibility: They can work around almost anything. However, you still need to include them in the planning stages to avoid conflicts. Say you're planning to have some recessed lighting in the kitchen below a bathroom. You need to know that it probably won't fit in the same framed bay as the ductwork or the sewer pipes. So you may need to rethink the layout of one room or the other to get your recessed lighting where you want it.

When you are planning the bulkheads and chase for the ductwork, keep the plumbing and electric in mind. They will both need a way to get to the basement to tie in to the existing service connections.

Ron Nodine owns American Renovator Inc., a Baltimore design-build remodeling firm, and former president of the Remodelors Council of the Home Builders Association of Maryland. Karol Menzie is a feature writer for The Sun.

If you have questions, tips or experiences to share about working on houses, e-mail Ron at Or write c/o HOME WORK, The Sun, 501 N. Calvert St., Baltimore, MD 21278. Questions of general interest will be answered in the column; comments, tips and experiences will be reported in occasional columns.

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