My previous blog was about adding a second story addition above a garage – somewhat difficult but not too tough. A more complicated project is to add a partial second story addition (i.e. a second floor) to an existing house. This type of project includes many of same challenges associated with going above a garage plus others unique to building above an existing living space (without wrecking the space below).
When adding a partial second story addition to an existing house these 7 things are critical to remember:
1) Determining the location of stairs up to the new space.
This is a planning and math exercise. Each person involved in this should be double checked by someone else on the team before the project is started.
2) Protecting the space below from inclement weather after the house roof has been removed.
Not much needs to be said here except that a plan needs to be in place on how the first floor will be kept dry while there is no roof on the house.
3) Protecting the drywall ceiling below from collapse during and after roof removal.
Once the roof rafters have been removed and the carpentry crew starts working on installing the new second floor, the possibility of the first floor ceiling collapsing or someone accidentally falling through the ceiling increases dramatically. Temporary walls may be needed on the first floor to prevent ceiling collapse.
4) Relocation of utilities in the existing attic (ductwork, wires and plumbing vents).
In the design phase for adding a second story addition, solutions to extending or eliminating existing attic duct work, wiring and plumbing vents need careful solutions. Nothing could be worse than having no place to run the sewer gas vent other than the middle of a room. By the way: duct work includes existing bathroom venting and cooking ventilation – don’t forget about determining how these will be effected.
5) Extending fireplace and gas furnace chimneys.
The code has very specific requirements for fireplace and gas furnace chimney height and proximity to windows. Forgetting to pay attention to these could lead to costly overruns.
6) Determining the impact of the additional weight of a second floor on the existing structure below.
The architect, structural engineer and contractor all need to work closely here. The architect for design, the structural engineer to make sure the building can handle the load and the contractor to provide cost and ease of execution input. Some solutions may look intuitive but may be budget busters. So all three team members need to buddy-up on this.
7) Analyzing the impact of the new space on the existing mechanical systems and what upgrades are needed (plumbing, HVAC and electric).
The special trades need to involved early in the design phase to assist the architect and contractor on what changes are necessary to the existing mechanical, plumbing and electric. The remodeling contractor needs to provide input to the special trades as to how their (special trades) solutions affect cost and execution. Many times the first round of solutions are not the final. After all trades talk there are typically modifications to how the HVAC, plumbing and electric will be installed.
These 7 critical things to remember are not even close to all that must be remembered when adding a second floor addition to an existing house. But hopefully they will help you avoid some of the more expensive oversights.
Once again, thanks for reading our blog. I hope the content is valuable – I am striving to provide real answers to real remodeling challenges so once you start down that road you are doing so with your eyes wide open. Please feel free to comment or leave questions via the links below.