Room Additions that Work

p 2002 By Janet Short

Designer for Wayne Short & Co., Poteau, OK

            Adding a room to your existing home is a great way to get that extra space your family needs without having to relocate and go through the major upheaval of building a whole new house. Before you start buying lumber or signing contracts, here are some of the things to be considered.

            In the scheme of your existing home, where will the addition best be located?  Existing patios, porches or carports are favored places to enclose.  The advantages are obvious: there’s a doorway already, a floor and sometimes a roof.  However, there are also problems inherent with this plan.

Patios, porches and driveways usually don’t have the same footings under them as the house.  If these areas are going to be converted to living space, the footings must match the rest of the house and be “tied in” so that one part of the foundation isn’t moving about and causing cracks in the walls and leaks in the roof.

An engineer, architect or home designer can help you find out if the foundations will work or determine what will have to be done to make them work.  If there is no reinforcement in the existing concrete slab or floor, it may be easier and cheaper to start with a new slab.  If that’s the case, it can be built most anywhere that the roofline allows.

The roofline can be one of the trickiest parts of designing a room addition. The new roof needs to match the existing one, not only in materials but also in design.  The existing pitch or slope is most always matched.  If your home has two different roof pitches they should be noticeably different – never almost alike.

In most cases the width of the new room cannot exceed the width of the main body of the roofline or it will cause the new roof to stick up above – like a flag announcing, “I’m added on!” 

If you have a covered patio or drive-through it will already have a roof.  It must be weather-tight and able to receive insulation. A drip or two may not have mattered on weather-resistant patio chairs ¾ but now this room will house more vulnerable furnishings.

Another consideration, of course, is the building easements.  There will be some restrictions as to how close your addition can be built to the edge of your property.  Property deeds have plats or plot plans attached to them and the person who helps you design your room addition will need to see a copy of this.

If there is going to be plumbing in the new room, pipes and drains will need to go under the floor.  Concrete-reactive materials must be sleeved to prevent corrosion. If you use a septic system, it may need to be enlarged or expanded to accommodate the addition of a hot tub or washing machine. These are a few of the many things that must be taken into consideration when your design is drawn up. 

Heating and air conditioning loads will need to be calculated.  If the new space is very large or has a lot of windows, an additional HVAC system may be required.  In our hot, humid summers, a commercial-type window unit or through-the-wall unit can be a real comfort-saver.  Some of these will also provide enough heat for a medium-size room.

Last, but just as important as everything else, the new addition to your home should be aesthetically pleasing.  Ideally, the style and materials ought to match the existing home. 

Styles are often hard to define.  What one architect calls Victorian, another may label as Queen Anne.  But a trained eye will see that arches and fascia sizes and other style elements must match exactly, whatever the name.

If materials cannot be matched (as is often the case) it is best to use something totally different.  For instance, if your brick color can’t be found, you might want to use redwood siding or a contrasting rock on the new addition, rather than creating what looks like a mistake.

A thorough set of building plans will take all these points into consideration. Specifications will spell out all the details of materials and appliances to be used.  Many architects and designers also offer to inspect your job as it is being built, catching mistakes before they are “sealed in concrete” and helping to avoid conflicts between the homeowner and the contractors.

 Adding on to your home, as you can see, entails most of the same steps as building a new one, but on a much more manageable scale.  It’s your home, one of the largest investments of your lifetime.  If you allow plenty of time for communication with the architect or designer and give lots of thought to what you really want, your room addition can make your home a more livable place!