Turning your attic into living space involves the same sealing and insulating tasks described for unvented attics. It also involves structural factors.
Many attic floors are not designed to handle the added load of furniture and active human bodies. Check with an engineer and your building department to determine whether you need structural improvements. A worst-case scenario could require you to beef up your framing and foundation. If you’re lucky, your home is adequately constructed for your planned conversion.
New Utilities for a Converted Space
Adding new heating, cooling, ventilating, lighting, and plumbing involves similar issues, whether you’re converting an attic, garage, basement, or porch.
Have an HVAC pro determine whether your existing equipment has enough capacity to heat and cool the new room. If you have a forced-air system with adequate capacity, you may only need to add new ducts and fans. Once the new equipment is installed, have a professional balance the airflow for the entire house.
If your existing equipment doesn’t have enough capacity to serve your conversion, it may be cheaper and more effective to add a self-contained heat pump/air handler that can provide heating and cooling in a single, easily maintained unit. For a smaller converted area, a portable A/C or heater, or a ductless mini-split heat pump, may suffice. You might add a baseboard heater or window unit A/C, but keep in mind that the low initial cost of some stand-alone equipment may be more than offset by higher energy consumption, and therefore higher operating costs.
If you’ll be adding more electrical outlets, consider including a new 20 amp circuit, with wire run to any points as needed. If a bathroom, wet bar, or kitchen is part of your conversion, consult a plumber before developing detailed floor plans. All wiring, ductwork, and plumbing should be in place before you insulate or finish the walls, floor, and ceiling.