How to Convert a Flat Ceiling to Vaulted

A vaulted ceiling creates a sense of openness and space in a home. Even though the footprint of the home remains the same, vaulting a ceiling with trusses makes the house feels larger and airier. When combined with skylights and windows, a vaulted ceiling introduces more natural light to the home.

Flat ceilings (approximately 8-foot-high) built on a conventional truss system can, in most cases, be expanded upwards. Typically a project tackled by a contractor, the cost to convert a flat ceiling to a vaulted ceiling can run you $18,000 to $35,000, adding major resale value to your home. But with a little engineering know-how and some solid carpentry skills, this project can be tackled by experienced DIYers. Make sure to secure a permit to vault a ceiling before starting, and consult an engineer who can advise you on structural safety.

Basics of Creating a Vaulted Ceiling From a Flat Ceiling

Whenever a home’s structural element is removed, another element must replace its function. Every part of a roof truss is crucial to the structural integrity of your home and must be attached to a load-bearing wall. Creating a vaulted ceiling means removing parts of the roof trusses. So, the removed pieces must be replaced in other ways. You can also remove ceiling joists when raising your ceiling, but you'll need to install temporary supports until the final structure is sound.

Structural Safety

One method of vaulting includes removing all pieces of the roof truss except for the rafters. To compensate for the missing pieces, the rafters are supported along their sides by two-by-ten boards that are nailed to the rafters—a process known as sistering. Adding two-by-tens to the rafters not only provides more structure, but also allows space between the roof and ceiling for insulation and light installation.

Sistering the rafters isn’t enough, so collar ties, or collar beams, must also be added. Collar ties are short studs that run horizontally from rafter to rafter, yet are located much higher and closer to the roof ridge than the ceiling joists. Essentially, the collar ties perform the same function as the removed joists, but on a smaller scale. These structural supports will always need to be put in place if you're raising a ceiling into the attic.

Roof Ventilation

Vaulted ceilings need to be appropriately vented to assure no heat builds up between the underside of the roof and the finished drywall. You can do so by installing soffit vents and gable vents to allow fresh air to move in and circulate. Soffit vents need to be installed in each rafter bay, making sure there is an intake and an outtake vent. Two gable vents on each side of the peak will also assure proper airflow and keep your roof dry.

VAC Ducts and Electrical Wiring

You'll also need to consider the ductwork and electrical rewiring when raising your roof. Both projects should always be tackled by a certified professional so that the end result functions properly and safely. You may want to attempt to move wires yourself, but to assure you pass inspection, it's best to hire an electrician. Additionally, a larger HVAC system may be needed to both heat and cool the larger open space. An HVAC professional can advise you appropriately.

Existing Chimneys

In most cases, existing chimneys don't pose a problem when vaulting a ceiling. Just make sure the part of the chimney that was originally housed in the attic is finished. If it was not, you'll need to add this expense to the overall cost of the project.