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What to Consider With a Second-Story Addition

Adding space to your home at the second or even third story can capture views, maximize square footage on a small lot and let you locate all the bedrooms on a single level. However, all that space can come at a high cost. A second story can greatly impact the rest of your home, which often means structural reinforcement on other levels.

Here’s what to consider before adding another story to your home.

Whole-house impact

The design and function of a second-story addition will have a ripple effect on the rest of your home, everything from finishes to mechanical work to structural work. A good design will make the second story look like it was always intended, so take the necessary time to ensure the addition favors your curb appeal and your home’s functionality.

Structural requirements

A second story with occupied rooms will weigh much more than your old roof system, so engineers need to calculate how much weight the main-floor walls and foundation will carry and how to hold that weight up. Second stories require structural support, including adding plywood and steel connections at main-level walls and down into the foundation to meet code requirements. This is particularly important in areas with seismic risk and with older homes.


A new staircase usually means taking a bite out of your existing main-floor rooms, which can impact the use of those rooms and the traffic flow. Sometimes it’s a no-brainer, like over existing ones going to the basement. But sometimes, a little creative thinking is required.


When you add a story to your home and have a masonry chimney, you need to eliminate it or build it up (with brick or a metal flue) to above the roof level. This can be a simple decision, particularly if you never use your fireplace or want to convert it to a natural gas fireplace.

Windows, doors and siding

If structural work at the main level requires removing half of the siding, you may wonder whether or not the whole house should have new siding. If main-floor windows and doors are tired, rotting, don’t meet the energy code, or are simply out of style, should they all be replaced? Making these decisions early in the process is key. Going back to order windows for half a house when the project is already started is sure to cause delays.


When engineering requires old siding and sheathing to be removed from your home’s exterior, it also presents the chance to install new insulation. Homes built in the 1950s tend not to have insulation in their walls. Installing fiberglass batts or even rigid insulation in the studs is a great way to improve the energy efficiency of your whole home.