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.
Mechanical. Your furnace, water heater and electrical panel all work based on your home’s square footage and the number of fixtures you have. When you increase the size of your home, you have to revisit all of these systems.
Electrical panels are typically upgraded to 200 amps, and HVAC systems can be replaced, added on to or have new zones added, depending on whether they are forced-air or radiant systems. Hot water can be delivered in a number of ways — from tankless heaters with recirculating pumps to tank systems and separate on-demand systems just for a master bathroom. You could consider adding an energy-efficient system too, such as ductless heat pumps, geothermal heat pumps and solar-assisted hot water or photovoltaic panels.
Chimneys. When you add a story to your home and have a masonry chimney, you need to eliminate the chimney 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 to a natural gas fireplace.
It’s also possible to save a wood-burning fireplace and remove a separate mechanical chimney by replacing older equipment with new energy-efficient units that can vent horizontally (instead of vertically). The space that a mechanical chimney took up can also become a convenient chase for ductwork, plumbing or electrical to run to the second floor.
Windows, doors and siding. The key elements of the building envelope become big question marks with second-story additions: Should you match them? Start over? Do half and half? 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 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.
Roofing. Part of the demolition process for second-story additions is removing the entire roof system. A contractor experienced with these kinds of remodels will have protection systems to keep rain out, but it won’t be feasible to live with them.
A project of this size nearly always requires vacating your home for the duration. But you’ll get to move back into a home that’s doubled in size and is 100 percent ready.