Is It Cheaper to Build a Gambrel or Gable Roof?

Stick-Framed Rafters

• Whereas a gable roofline consists of two flat planes, one on each side of the roof, the gambrel roof has four separate planes. The top slope of a gambrel roof features a slight slant but the second plane is a much steeper slant. If the builder is stick framing the rafters, not only will a gambrel roof require more lumber, the builder must figure additional angles for cutting and framing. The lumber cost to build a gambrel roof is slightly higher than that of a gable roof, but the labor cost to for the gambrel roof could be up to twice as high because of the extra work.

Pre-Engineered Trusses

• The alternative to stick framing is the installation of pre-engineered roof trusses. If you opt to install roof trusses, the gambrel roof will likely be slightly higher, because more lumber is used to construct the truss members. Labor cost to install the trusses, however, should be comparable because the trusses come pre-assembled and both are set in place with a crane and require similar installation techniques.

Roofing Cost

• The cost of shingles and roof sheathing for a gambrel roof may be nearly twice as much as the cost of roofing materials for a gable roof. Because a gambrel roof extends lower over the sides of the house or barn, however, you won't have to buy as much siding to finish those two exterior walls. Labor charges are higher to install the shingles on a gambrel roof. The steep lower gambrel roof planes are treacherous for workers and might require the use of scaffolding for safety. Installation will likely be slower, at least on the lower planes, which adds to labor costs.

Other Considerations

• While a gambrel roof costs more than a gable roof to build, it offers more square feet of usable living space if you want to finish the loft or attic area. Much of the attic beneath a gable roof is useless once the interior ceiling slopes lower than 6 feet. If additional living space is important, you’ll have more if you build a gambrel roof.