IS THERE ROOM FOR THAT ROOM?

So you’re thinking of building an addition in that unused piece of yard. Should you call in an architect?  Maybe.  But before you hire a professional, you may want to do a little legwork first to make sure your idea will comply with local zoning laws. You’ll save time, money, and arguments with the neighbors by ruling out unworkable schemes at the outset.

A typical plot plan. The heavy black lines are property lines.
The dotted lines indicate the setbacks.
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First, call your zoning department to find out the setbacks and height limits for your property. Remember, just because you have some empty ground doesn’t mean you can put an addition on it. Every residential property has a setback on each side—an area in which you’re not allowed to build. When requesting zoning information over the phone, give the zoning official your street address or, better yet, your Assessor’s Parcel Number (it’s on your property tax statement).  The zoning officials may require a day or two to return your calls, but be patient. Don't even start thinking about an addition until you have all the setback requirements in hand.

A typical city's table of setback requirements.
Every city is different, so don't make any assumptions.

Next, if you have the original blueprints for your house, look for the sheet titled site plan or plot plan—it's usually the first sheet of the drawings. It will show the distance from each side of your house to the property line. If you don’t have the blueprints, you may have received a small 8 1/2” x 11” size plat map with your deed when you purchased the house. The plat map will show the size of your property, although it won’t show the house.  If you can’t find this little map, the Tax Assessor’s office can provide you with a copy for a small fee.

The site plan or plat map will give you the basic dimensions of your property, as well as indicating potential problems. Beware areas with dashed lines labeled R.O.W. (right-of-way), reserve, or easement. These areas may contain public utilities such as sewer lines or overhead power lines, or they may be reserved for future utilities. Even though  you own the property, you usually cannot build on these areas. You can pave or landscape them, but the utility company nevertheless maintains the right to remove anything that’s in their way in order to access them.

Here's the buildable area that remains
on this simple rectangular property. Your existing
house will already have used up most of it;
what's left is where your addition will have to go.

If you’re thinking about a second-story addition, guesstimate the height of the completed addition and make sure it doesn’t exceed the local height limit. Take a look at the neighboring houses: If none of them have second stories, there may be a good reason for it. Height limits generally aren’t a problem, but check anyway. You know that old saw about making assumptions.

After you’ve determined your setbacks and height limits and checked for R.O.W.s, reserves, or easements, subtract these areas from your property. You can do this on paper or by actually measuring from your approximate property lines. What's left is the buildable area.  Don’t be disappointed if there's a lot less room to build than you thought. A good designer or architect can usually work around a tight site, and it’s better to have a realistic idea from the outset rather than wasting a lot of time on an impossible scheme.