Whether you live in an urban townhouse or country cottage, all homeowners share a similar desire for more space, specifically another bedroom. Many times, however, building out or onto the home's current framework isn't feasible.
The not-so-obvious solution is to build up, into the home’s attic, where an already existing footprint provides an instant roof and subfloor, two huge expenses of any rebuild. After that, the amazing attic remodel can begin.
Here are the need-to-know costs and considerations of the complete attic-to-bedroom conversion:
“Rule of 7”
The average cost of an attic renovation is between $40,000 (low end) and $80,000 (high end) depending on whether the space needs retrofitting to meet official building codes of structural integrity, safety and efficiency. Whatever you put in, however, will be handsomely rewarded, as a recent National Association of Realtors report claims you can expect to “recoup up to 62% of investment.”
The first step is to make sure your attic satisfies the “Rule of 7,” which mandates the space be 70 square feet in size, with no less than 7 feet in any direction. So, even though a 5-by-14 foot space equals 70 square feet, it doesn’t qualify as one of those lengths is under 7 feet.
Also included in this rule is the requirement that at least 50% of usable floor space have a ceiling height of 7 feet or more.
Another strict code of attic renovation mandates at least 8% of usable floor area must be glazed, as in contains windows. Additionally, at least half of those windows must be openable to provide an exit in case of fire.
The cost of window installation ranges from $3,000-$20,000, depending on a number of factors, including the shape and pitch of your home’s roof, whether you choose dormer windows or skylights, and the style of window pane and framing.
While one of the most expensive parts of the remodel, the addition of windows to your attic is essential for providing natural light, ventilation, creating a sense of expanded space, and an escape.
Building codes require that live-in attic spaces be able to maintain a temperature of 68 degrees Fahrenheit at any given time. The first step to achieving this is sealing all and any cracks, gaps, and creases between window units, doors, walls into unfinished parts of the attic, ceiling fixtures, the chimney, light switches, and so on. After that, homeowners may decide to regulate temperature via a low-cost option of ceiling fans and window AC units, which run $500 for two units.
The more substantial option is to install a fully-functional HVAC system complete with heat pump and ductwork, which can run up to $6,000.
A critical component of temperature control is proper insulation, which not only benefits the attic space, but the entire home’s overall resistance to mold, moisture, pests, water vapor, and sound. A high-quality, high R-value insulation -- options include batt, barrier, blown-in, or spray-foam -- runs between $600-$1,800 for 200 square feet, and has one of the highest rate of investment of any structural upgrade (107% ROI in 2017).
A basic roof inspection, which averages $250, must precede any attic renovation, as worn shingles or deteriorated flashing are certain to cause leaks into the lower living area. Costs beyond that will depend on the type of issues found. Inside, it’s recommended the roof be supported by A-shaped rafters over the less-substantial W-shaped trusses.
Depending on the severity of mold issues, remediation can cost between $1,500-$10,000 for the most critical cases (although you may have none).
Putting in drywall, installing trim and moldings, painting, and any other treatments will cost between $900-$2,800.
Ordinarily, an attic floor is built to hold dead loads, as in stationary furniture, boxes, and storage. First and foremost, the new base must be reinforced with added joists and insulation to support moving weight. The most obvious option for optimal sound absorption is carpet over a plywood subfloor: $1,500. More expensive options include hardwood and laminate wood alternatives (upwards of $3,000).
Building regulations require that all living attics be accessible from the lower level via a staircase. The pull-down rope ladder isn’t code compliant. Also, the staircase must provide a minimum of 7 feet in headroom the entire walking length of the stairs. A traditional straight-run staircase will eat up the most square footage, but is the least expensive option at $550-$2,800. A more convenient, space-saving option is a spiral stairwell, in forged iron, steel or solid wood ranging from $2,000-$6,000.
If you decide to add a fully functional bathroom to transform your attic into an in-law suite, expect to pay an average $1,500 to retrofit plumbing. Also, choose to build the bathroom near the existing DWV system to reduce demolition needs.
The final step to converting your attic from a dark cave into a bright bedroom is electricity. Expect to pay between $2,000-$3,000 to cover the costs of installing a new electrical panel to support the increased load and mounting any recessed lighting, ceiling fans and other fixtures.