Q&A for How to Build a Hip Roof

The four exterior walls of buildings with a hip roof usually tend to be load bearing walls. These walls are supporting the roof rafter ends, bearing their weight load.

A hip roof design refers to a roof where the roof sides slope downwards from a middle peak, with the rafter ends meeting the exterior walls of the house. Each of the four sides of the roof slope downward, there are no upright or vertical parts, no gables, etc., on a hip roof. The hip roof can have all four sides the same measurement or two long sides and two short sides. The slope of a hip roof tends to be the same for all four sides. More information can be found about the shape and design features of hip roofs in Wikipedia’s article on hip roofs, then you can return here for how to build yours!

A hip roof has roof panels on all four sides, while a gable roof has only two. The gable roof (also known as a pitched or peaked roof) is ideal for ease of snow removal but is prone to lifting in high winds and needs bracing if it’s used in areas that have high winds and hurricanes. Hip roofs tend to be stronger than gable roofs but there is an increased cost in building a hip roof as it’s a more complicated structure that requires more building materials and effort. While hip roofs are stronger and more wind resistant, they can be prone to leaks due to the increased level of joins required, so care must be taken to provide proper water protection at all joints.

A Dutch hip roof is a combination of both the hip roof and gable roof features. It is sometimes also referred to as a Dutch gable roof, precisely because it contains both roof style features. The gable portion of a Dutch hip roof is usually placed at the end of the roof ridge and sits on top of the plane of the hip roof. It’s a little hard to imagine this just by reading words, so it’s a good idea to do an image search for this roof, so you can picture it with ease.

This will depend on the length of the rafters. Consult the span tables.

Yes, if the common rafters are 10 feet or longer it is a good idea to put collar ties on.

Every 4 inches or to your local building code specifications. Be sure to consult your building code as to what type of fastener is required or recommended (ring shank, screw nails, etc.).

Figure the length of the plywood and appropriate that to the square footage of the house.

Typically 5/12 (every 12" have a 5" rise) but other factors like wind, rain, snow come into play. A 5/12 pitch may handle 10" rainfall zones but may not be enough for southern rains of 20+ inches or melting snow, which will typically need 30 degrees or a 7/12 minimum roof pitch. Check your resources for local rainfall, snow accumulation, and wind zones to select the best pitch.

To find the length of the ridge you measure the length and width of the building to and from the building line. Subtract the shorter wall length from the longer wall length and add 1.5 inches for the ridge beam.

There's this formula to figure out how much plywood you will need. Add the areas of all the sides together to get the total area of the roof. Measure a sheet of plywood sheathing and multiply its length by its height. Divide the area of the whole roof by the area of one plywood sheet to figure out the number of sheets you’ll need.

It depends on the roof pitch. Use a quality carpenter's square and refer to the table inscribed on it (instructions for use of this table are included with any new square).

Expansion foam. You can get it at any hardware store. You can cut/shape it as needed once it has cured. Just spray it in the area you wish to block off until it is filled, let it cure and then clean up any excess.

I have seen this done in older buildings where ceiling joists are put in place on the wall head; the bottom side of the common rafters are then fixed to the ceiling joists and the space between the joists/rafters is filled in with brick, mortar, cement etc. Make sure to use the correct damp-proof course to create a barrier between the timber and the cement. Alternatively, a wall plate/headbinder could be fixed around the head of the wall and then doubled up, allowing an easier fixing for ceiling joists, rafters, joist hangers, etc.

If this is your first one, I would recommend screws so you can easily remove them if you make a mistake.

Go with 2x6, think snow load and the weight of workers laying/replacing the roof.