Constructing A Vaulted Ceiling

Very often homeowners want to change the construction of their ceiling to open up a vaulted ceiling. In many cases a vaulted ceiling will open the feeling of a room and create air and light in a room. However, this is a substantial remodelling project and should be approached with care and the help of a residential structural engineer.

Structural Support

Most flat ceilings hide potentially gorgeous open-rafter cathedral ceilings. However, substantial structural issues must be taken into consideration before beginning any tear-out project in preparation for constructing a vaulted ceiling.

The cross supports for most flat ceilings have the structural function of providing thrust against which the roof rafters stand. If these horizontal cross supports are removed, then the homeowner runs the significant risk of the roof sagging and eventually failing because of lack of cross support. As a result, if you are considering removing a flat ceiling in favor of constructing a vaulted ceiling, first investigate how to brace the roof with an alternative method of supports for the rafters.

A few of the options for alternative structural support include placing a very sturdy, strong center roof beam along the roof peak line and attaching all of the rafters to this center beam. If this method is used, then the roof beam will need to be supported at each end by a column that solidly rests against a firm ground surface. Columns can be supported with a concrete footing or be attached to a steel I-beam that supports the floor or the foundation.

Another alternative structural support which involves substantially more time and effort is to construct entirely new roof rafters that rise closer to the roof ceiling.  Rafters can be designed so that they provide overall support through a series of smaller cross rafters that are combined into each larger spanning rafter.  Not only does this structural design provide significantly more support, but it also adds overall visual interest to the vaulted ceiling.

Sky Lights

With the rafters in place, it is easy to install sky lights at desired locations in the vaulted ceiling to allow additional light to filter into the room. Additionally, newer sky lights have the ability to be opened—either manually with a crank mechanism or with a small electrical motor—to allow for venting of hot air. This feature can be especially attractive if you live in area with extremely hot summers where accumulated hot air at the top of the ceiling can reduce energy efficiency.

Vaulted Ceiling Insulation

There are several different options for installing insulation in a vaulted ceiling. One of the easiest options is to install rigid insulation sheets over the rafters, providing not only insulation but also the structural function of enclosing the roof. Another type of roof insulation is spray foam insulation, although venting space will need to be included unless newer breathable insulation materials are used. Finally, traditional fiberglass insulation works well in cathedral ceilings, although a 2-inch breathing space between the insulation and the roof sheathing must be included with this kind of insulation.