Why Tiny House Roof Thickness is Important (Explained)

Choosing a roof for your tiny home can become a project itself.

The type of roof your tiny home has emphasizes the character of your home as it’s one of the first features people will notice.

Not only are there numerous different styles of roofs to choose from, but there are also various materials and pitching methods.

But it’s important to remember the main purpose of your tiny house’s roof, which is to protect the interior of your house, your personal belongings, and your family from the elements. 

One resounding question we’ve seen while researching tiny house construction is what should my tiny house roof thickness be?

The simple answer is it depends, and it depends on quite a few factors.

Tiny house roofs can be made of various materials, which dictates the thickness of your roof.

Below, we go into depth about figuring out how thick your tiny house roof should be and why it’s so important to get right.

How thick are tiny house roofs?

The thickness of tiny houses ranges because of different pitch styles, material choices, and overall preference of thickness.

A minimum thickness of 18mm is recommended, with the average thickness being about 2 and ½ inches, but can run between 3 and 5 inches.

The thinner your roof is, the more likely you are to face insulation issues.

If you do choose a thinner roofing material such as metal, it’s smart to give the pitch an incline to help water drain off your roof.

What determines tiny house roof thickness?

The thickness of your roof will depend on the structure of your tiny house, the materials you choose for your roof, and the pitch.

A typical tiny house is 12.5 feet high and 8.5 feet wide, and between 20 to 23 feet long. A tiny house can technically be up to 30 feet long and still fit into the tiny house category, but keep in mind the longer your tiny house is the harder it becomes to tow.

Tiny house roofs are nearly all made up of the same key components: rafters or trusses, and sheathing, and shingles. 

Rafters and trusses are the structural support beams that create the pitch of your tiny house and support the weight of your roof sheathing and shingles. 

Rafters will vary in size and thickness, depending on the pitch and the span of the roof. The general rule of thumb is that your roof should have at least 2/12 pitch, which means that for every foot of run your roof should rise 2 inches.

For tiny houses on wheels, it’s recommended to go for a 4/12 pitch, as your house may be parked on slopes or slanted pavement, and this will ensure water can’t pool on your roof.

You of course can choose to go shallower or have a flat roof, but they require a little extra work to execute perfectly. 

Trusses are not as thick as your rafters, but they have the ability to hold heavier loads than rafters can. They are made of engineered wood.

The exact dimensions of your trusses will depend on your roof’s makeup and needs, but generally speaking, trusses can support a roof load as much as a 2-8 rafter. 

The sheathing is the material that will go on top of your trusses or rafters. The standard thickness for sheathing is about ½ inch, and it is almost always made of wood.

If you choose to have a thicker rooftop, your contractor may recommend a ⅝ inch thick sheathing material. 

Adding shingles to your rooftop can add both weight and thickness, especially if you choose to overlap the shingles for design purposes.

The average thickness of shingles is around 3/16 but varies depending on the material you use. But for shingles, being aware of the weight is more important than the thickness.

While double layering of shingles is acceptable, triple layering is usually not recommended, as it adds a significant amount of weight to your tiny house’s roof and there’s a stronger chance of the wind knocking your shingles loose.

Why roof thickness is important for tiny homes

The tiny house roof thickness is important because it will dictate quite a few things.

A thicker roof will help your tiny house withstand harsher climates with bad weather spouts, and offer better insulation.

Thicker roofs provide a better barrier from rain, wind, and snow, and the thickness could help prevent serious damage from occurring. 

For example, if there was a leak in your tiny house’s roof, a thicker roof could help prevent erosion of insulation, as well as mold build-up in your insulation and your ceiling.

It’s important to understand just how much your roof will weigh, this will be heavily dependent on the thickness of the materials you choose for your roof. 

A thicker roof can also almost guarantee longevity.

As stated above, it’s hard for the elements to penetrate your home when you have a thicker roof.

Well it’s harder for them to damage a thicker roof because there’s a lot more holding the thing together. It may cost you a little more upfront, but investing in a thicker roof can save you money down the line.

How do different roof pitches affect thickness?

There are many different roof pitches to choose from for your tiny houses, with some being better suited for you and your lifestyle and others not making sense.

Most tiny houses tend to have either a flat roof, shed roof or gable roof.

For instance, if you’re looking to add a rooftop garden to your tiny house, you will want a flat roof, but you’ll also want it thicker than most flat roofs to prevent any damages from constant use.  

Regardless of the pitch you choose, certain styles of pitches will affect your tiny house roof thickness. This is because there are materials that must be used with exact pitch heights due to their weight.

Aluminum and steel shingles and steel through-fastened panels are an example of this, as they need to be used on at least a pitch of 3/12.

Summary

Tiny house roof thickness is an important factor in keeping your property safe and secure.

It’s important to understand how much weight the frame of your tiny house can handle before moving forward with any roofing plans.

The thickness of your roof will rely heavily on the strength and size of the rafters or trusses installed during construction, as this will dictate the thickness of the sheathing and shingles you can use.

A thicker roof helps ensure your house is extra protected from the elements. If you live in a climate that’s more prone to harsh rain and snow, it may be in your best interest to invest in a thicker roof for your tiny house.