Home Home Design How to Build a Mansard Roof – Steps to Constructing and Preparing

How to Build a Mansard Roof – Steps to Constructing and Preparing


Commonly considered a hip roof, the mansard roof – sometimes called the French roof – was a popular style roof centuries ago. The mansard roof may not be as popular as it was in the Victorian era, it is still well known across the country and is still a very popular roofing choice among homeowners.

What is a Mansard Roof?

A mansard roof is a type of roof that has four sides and two sections. The two sections are actually a lower and an upper section. The lower section of the mansard roof consists of a very steep vertical slope on each one of the four sides of the roof while the upper section of the mansard roof insets from the roof’s edge with a near vertical rise.

Why Choose a Mansard Roof?

The primary reason that homeowners choose a mansard roof is because it creates additional living space on the inside of the home just under where the roof is constructed. In addition, it creates a very unique, delicate appearance to the exterior of the home.

Preparing to Build the Mansard Roof

The mansard roof may be complex overall, but the framing of this style of roof is not. Not only will homeowners save time in building the frame for the mansard roof, but money will be saved.

  • Start with a floor plan. You should never start any project without a floor plan. A local roofing company would begin with a floor plan, so you should as well. You can add elevations and make changes to the floor plan to create your own style preferences. If you aren’t doing this alone, this part would be performed by an architect or builder.
  • If you are tackling this project on your own, you will need to take measurements and factor in several different aspects (such as weather considerations) before creating the final design of the mansard roof for the home. If you are working with others on this project, the person that would perform this part of the job is known as a structural engineer.
  • When choosing materials for your mansard roof, you will consider your budget, how long you are aiming for your roof to last before replacement, the area’s climate, etc.
  • Before actually performing the build, be sure to contact your local city hall or code office for requirements for the building. You will need to set up inspection dates and obtain specific permits, as outlined by your city or county law.

Steps to Constructing the Mansard Roof

  • Prepare for construction.
  • You will start by nailing common rafters on the initial ridge board. You will then raise this ridge board to nail in opposing common rafters. The bird’s mouth line should line up with the top plate of the wall, which is when you would nail the outside rafters. You will continue to do this along with all four sides of the mansard roof.
  • You will then continue to nail the common rafters until finished.
  • Nail the ceiling beams and then lay the sheathing.
  • The upper section of the mansard roof is built with vertical rafters being set inside the ridge board. You will want to brace this area with common rafters not just on the inside but the outside as well.
  • Collar ties should not be nailed on as well as fascia prior to sheathing the roof. Sheathing should then be nailed to the common rafters. Flashing should be put down around the vents and valleys.
  • Now, it’s time for the undercoating to be put down as well as the shingles and any architectural accents.

Mansard Roof Design ideas gallery