The 5 Most Important Things to Consider:
1. Location of Stairs/or Existing Stairs to Code
Often the hardest thing to do when adding a second story is to find a location for the stairway. If there is an existing stairway to the basement, a new stairway may be located above the existing stairs or perhaps an existing small bedroom can serve as a new stairwell. Steps can be no taller than 7-3/4". Some existing attic steps are 8' tall or more.
2. Floor System Adequate?
Most ceilings are framed with 2x8 lumber. Most floors systems need to be 2x10 to meet code and not be bouncy. It is important to check before assuming that the existing ceiling can be the floor. Raising this 2nd floor system 2-3" will also affect the stairs.
3. Foundation Adequate?
The existing foundation should be checked to see if it is adequate to hold an additional floor if adding a second story. It is not an issue if you are just finishing the existing space. Beware of basements or crawl spaces that have been dug out lower than the foundation footings. Additions are still possible but an engineer may have to design foundation structural elements to make the addition possible.
4. Insulation Requirements?
The best insulation for an attic is the open cell spray foam. Adequate R value can be achieved in less space. If you use traditional fiberglass batts, an air space needs to be left between the roof and insulation requiring the rafters to be enlarged or furred down.
5. Heating and Cooling?
It takes approximately 1 ton of air conditioning to cool 600 square feet of living space, even more if it is directly below a roof or above a garage (bonus room). Don’t count on our existing system to handle the extra heating and cooling load. Be sure to allow a place for a heat pump and ductwork or use a PTAC unit (similar to a motel HVAC) to condition the space.
Harbour Towne Construction