Tiny House Roofing

bySavannah Dodge/February 15, 2021

TINY HOUSE ROOFING

When designing your house (of any size) you must determine what you want your tiny house roof to look like and how you intend for it to function. Are you going to be adding solar panels, do you want a green roof or rainwater catchment system? You must consider how your roofline is going to affect the interior space, how will it shed snow and/or rain? Do you want it to look modern, funky, rustic, traditional, ETC? Do you want a sunlight or clerestory window? These are all of the questions we must ask you at B&B Micro Manufacturing before any construction actually begins on your tiny house roofing.

SHAPES

As I am sure you have noticed, roofs take form in a variety of ways. From the traditional triangles atop a rectangle that we drew as kids, to the innovative shapes of modern architecture. Roofs allow for the design of your structure to blur the lines between form and function. Adding yet another layer to which you can express your creative vision. Below we outline a number of rooflines to provide you with inspiration for your own tiny, small, or traditional structure. B&B Micro Manufacturing has a wide range of rooflines for each signature model as well as our past builds for you to choose from.

SHED

The shed roofline is one of the most popular within the tiny house community. It is a simple ‘less is more’ design, that allows for flexibility in both form and function. With one simple slope in any direction, the shed is able to shed snow and rain effortlessly *pun intended*. It also can provide a great base for those solar panels you’ve been dying to invest in!

See our Portable Luxury Restrooms to the left

GABLE

One of the most classic rooflines to be seen in the global history of architecture is the Gable. Dating back to Ancient Greek architecture with the creation of pediments supported by columns, to the facades of the Italian Renaissance, all the way to the founding of America within the Northeast. With its triangular shape, the Gable provides both structural and visual strength to any structure.

See our Green River Small House to the left

GAMBREL

The Gambrel is much like a continuation of the Gable. Where the upper triangular portion has a lower slope ratio in comparison to the one below which becomes steeper. Oftentimes also referred to as the Barn Style roof.

HIPPED

At first glance the Hipped roof might closely resemble the Gable … however, instead of being sloped on only 2 sides like the Gable, the Hipped is sloped on all 4 sides.

MANSARD

What the Gambrel is to the Gable, the Mansard is to the Hipped. Just like the Gable and Hipped look similar to one another, so do the Mansard and Gambrel. Yet the same differentiation between the Gable and Hipped is the same way to differentiate the Mansard and Gambrel … there are 4 sides, instead of 2.

BUTTERFLY

The butterfly roof is a popular one among modernist individuals who are looking for something aesthetically enticing. Composed of two angular planes that intersect one another to form a valley, creating a visual representation of butterfly wings. For those looking to have an environmentally conscious home, this is the perfect roof for you! The angularity of the roofline allows for larger windows, rainwater catchment systems, and a great place to put your solar panels.

See our Silver Lake signature model to the left

SKILLION

Skillion is almost like a reversed butterfly, where two different angled roof lines converge together at a 90-degree wall. This converging wall can be tall or short and usually hosts clerestory windows!

See the interior effect within our Ashmere signature model – shown to the left

SALTBOX

If the Gable & Shed had a baby, it would be the Saltbox. With one side extended to have a longer slope, the saltbox is able to increase the interior space of the home while simultaneously using fewer materials.

FLAT

Flat roofs are not commonly recommended on Tiny Houses, but if you choose to pursue this route, B&B would recommend using a closed cell spray foam to insulate the roof and an EPDM Rubber to create a seamless waterproof barrier for a roofing material.

See our Wheel-Pad model to the left

PITCH RATIO

Once you have decided on the shape of your roof, you must now determine that pitch (aka. the angle). So get ready for some fun refreshments on geometry and trigonometry!

12:12

The 12:12 ratio is a way to determine a roof pitch through its rise and run dimensions. To accurately describe a rise and run, think of a gable roof being cut in half to form a right triangle. The rise and run are depicted through the straight lines that create the 90-degree angle (the rise is vertical & the run is horizontal), while the hypotenuse represents the slope. The angle between the slope and the run is the pitch. (See the image to the left as a visual representation of this diagram … Span = Run x2 (entire width of the roof) & Diagonal = Slope)

Rise / Run is the pitch’s ratio

So for example, a 12/12 ratio (where both rise & run = 12) *our Green River Small House as seen next to the Gable roofline, is a 12:12 ratio*

If you wanted a LESS steep roofline you could use the ratio of 4:12 (where the rise = 4 & run = 12)

If you wanted a STEEPER roofline (think of an A-frame house) you could use the ratio of 18:12 (where the rise = 18 & run = 12)

Determining the Slope Measurement

So we know the rise and the run, how do we get the measurement of the slope?

Pythagorean Theorem: A2 + B2 =C2

A = rise .. B = run .. C = slope

Determining the Angle of the Pitch

Using Trigonometry’s sin, cos, & tan you are able to determine the angle of the pitch.

tan(theta)=a/b, you can solve for theta (the pitch) using just the rise and run

sin(theta)=a/c, you can solve for theta (the pitch) using just the rise and slope

cos(theta)=b/c, you can solve for theta (the pitch) using just the run and slope

MATERIALS

You know what you want your roof to look like, you know how to calculate the pitch … So what material is it going to be?

STANDING SEAM METAL

One of the most widely used within the tiny house community, Standing Seam Metal roofs are lightweight and durable. With a variety of color options, this roofing material allows for a higher degree of customizations, an attribute that is highly prized by tiny dwellers alike. Another benefit to standing seam metal roofs is the fact that they are designed with hidden fasteners. Providing another layer of protection against rain, snow, ice, and wind (as ice commonly builds up around fasteners, standing seam eliminates this cause for concern).

** Many metal roof warranties require a minimum of a 2:12 pitch ratio, keep this in mind as you design your tiny house roofing system! **

See our Hoosic signature model to the left

ASPHALT/FIBERGLASS SHINGLES

Asphalt/Shingle roofs are one of the most widely used in building as a whole. Tiny Houses on Wheels can/have & will use this option, however, there are a couple of drawbacks that you must consider first. While Asphalt/Shingle roofs are incredibly accessible and affordable, they are also quite heavy and have been known to blow off when traveling down the highway at 60+ mph.

See our Green River Small House to the left

CORRUGATED METAL

Corrugated metal, like standing seam metal, is both lightweight, and durable. It is also more affordable in comparison to standing seam, however, to fasten this roof you must drive a screw directly through it … essentially allowing for a hole in your roof.

Other roofing material

(not to be used for THOW, as they are too heavy and/or will not hold their own against the wind)

WOOD SHINGLES

Wood shingles provide a beautiful and unique roof design that can last anywhere from 20-40 years. However, wood is also highly affected by the numerous outdoor elements a roof must endure. From insects such as termites, warping from the hot and cold weather as well as the natural growth of fungi.

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TERRACOTTA TILES

Terracotta tile roofs have become a staple in hot and dry areas like Arizona and New Mexico for their beautiful aesthetic and durability. Resistant to the elements such as fire, wind, and rot terracotta tiles also provide incredible thermal properties, reducing heat loss and gain. However, they are very heavy, expensive, can break easily should something fall on them, and are not the most water-resistant/snow friendly. (Which is why you do not see them in the northeast)

COMPOSITE PANELS

Composite panels are factory-made consisting of aluminum/steel facing with a polyurethane core. Allowing for a single product to be used during the building process, reducing the construction timeline, labor costs, and greenhouse emissions. They are also incredibly customizable and durable, all of which makes them too expensive for the majority of buildings.

COPPER

If you’ve ever been to Boston, you’ve seen the beautiful copper patina that surrounds all of its streets (also think .. the statue of liberty). Copper is an amazing material as it actually becomes more durable as it ages, naturally creating a protective barrier that makes it turn from this wonderful orange color to an everlasting green .. This is what is called a patina. However, like composite paneling, copper roofing is incredibly expensive.