How to Frame a Gambrel Roof Addition

A home with a gambrel roof.
  • 30-60 hours
  • Advanced
  • 15,000-30,000
What You'll Need
Pre-Made Trusses or Lumber
Chalk Line

If you are planning at home addition project, you will need to look at roofs. There are a number of different styles and types of roofs. One of the best uses of space is the gambrel roof. A gambrel roof is similar to a hip roof but it actually has gables at either side.

Gambrel roofs are the sort of things that you will see on many barns because they make the best use of all the space available. Very little space is wasted in the pitch of the roof because the gambrel roof addition is so wide. Fitting your own gambrel roof addition to your barn or home isn't that complicated. As long as you follow a few simple steps you shouldn't have any problem doing this.

Step 1 - Plan

Work out how many trusses you will need to cover your roof. This will depend on how big the building is that you are building. The roof trusses should be spaced 16 inches apart so it's quite easy to work out the number required using a calculator and some simple mathematics.

Step 2 - Make Roof Trusses

If you decided to purchase pre-made roof trusses then there's no need to bother making them at this stage. If, however, you want to make your own then use the number and nails to create the correct size roof trusses for your home. 2x6 inch lumber will work well for roof trusses if required.

To make the first roof truss, lay out the pieces of lumber on a level piece of ground. Use stakes to hold the pieces of lumber where they are supposed to be and to prevent them from moving.

Step 3 - Cut Lumber

Use chalk to mark the positions where the lumber needs to be cut. Make sure that this roof truss has all of the right angles to build your gambrel roof. Once you have made the first truss you will then be able to use this as a template to make cutting and making the other roof trusses very simple.

Step 4 - Assemble

Once you have made the right number of trusses it's then time to fix them to your house by using 8 penny nails. Strap metal can be used to offer the trusses more stability if required.

All of the braces then need to be attached to the trusses using the nails. Dogleg braces are secured using a 2x6" board to stiffen the structure up.

Step 5 - Position

Once the trusses have been assembled they can then be lifted into the right position. Make sure that all the trusses are completely level before they are nailed into the joists of your floor.

Step 6 - Cover with Plywood Sheets

Cover the trusses using 3/4 inch plywood sheeting. If you live in an area of the country which experiences heavy snowfall then you must use thicker sheets to cope with the extra weight.

Step 7 - Waterproof

Now waterproof the plywood sheets so that water cannot cause damage to the plywood sheets.

Step 8 - Frame Windows

Any windows need to be framed so that they fit properly into the Gambrel roof. Then all that's left to do is enclose the ends of the roof and cover the surface of the roof in shingles.