Think of roofs as hats over the spaces of working, learning, living and playing. Roofs, first and foremost, keep us dry. They shed rain and snow away from buildings. A roof is part of an enclosure system that closes and protects people from animals, insects, and weather. Roofs differ around the world in their material makeup, pitch, or slope, and response to climate. Look at the Vernacular Architecture Journey8 to see how houses are shaped and covered differently in different biomes.
For example in tropical areas, roofs are pitched to shed rain. In artic areas, sloped roofs shed snow. In desert areas, roofs are flat to catch rain and to shield from the heat of the sun. Roofs are also different on different building types. Churches look different than homes, schools, office buildings, and factories. Roofs shapes are different depending on the structural type used. Available construction materials and local traditions of making create cultural connotations to roof structures. Local and national building codes also determine roof forms in urban areas. Roofs also shelter transition spaces like porches and open-air pavilions. Botanical gardens and greenhouses have glass roofs that let in the sunshine. Tents and canopies have awning material overhead and are light and transportable. Planted roofs or green roofs reduce urban heat island effect, prolong the life of the roof, absorb stormwater, produce oxygen, harvest native species and are beautiful! Solar roofs have solar panels or solar shingles that collect the energy of the sun to create electricity or hot water. Roofs are are expressions of local construction.
Keep a roof overhead!
Activity 1 – Gable Roof
One of the most common roof types is the gable. It has two sloped sides that rise to meet over a ridge beam. These roofs cover a repetitive truss structure and consist of a wooden truss (if in a house), a layer of plywood, insulation, a moisture barrier, and a metal, shingle, clay tile or slate roof. Variations in pitch, or slope, of the gables are regional as well as vernacular. A 1 to 2 pitch results in a 45-degree slope. A 4 in 12 slope is less. A Flemish roof rakes higher.When two gable roofs meet, they create a valley or sloped drainway. A valley is an area of a roof created when two roof lines intersect with each other at different angles. Draw and label the parts of a gable roof noting its pitch, or slope. Add a photo or drawing of typical pitch roofs and label their types.
Activity 2 – Hip Roof
A hip roof roof slopes on all its sides, leaving no gable ends. The “Hip” is created when the two sloping sides intersect coming together in a third sloping angle. A hip roof usually slopes on all sides. Draw a hip roof from above and then in section showing typical construction.
Activity 3 – Gambrel Roof
A Gambrel roof is much like a Gable roof, except it has a shallow slope attached to a steep slope creating a roof with two pitches on each side of the main center beam. A Gambrel is also called a Dutch Barn as it was a common form of barns in the Netherlands. Sometimes dormer are placed in the 2nd floor of a front-facing gambrel roof allowing for larger upstairs spaces. Draw a house with a Gambrel roof and draw a section through it.
Activity 4 – Butterfly Roof
The Butterfly roof is like a gable roof but reversed. The peak of the roof that is usually the highest is now the lowest creating a roof where rain flows down towards the center of the roof instead of out towards the exterior walls.
Activity 5 – Vaulted Roof
A vaulted roof has a semicircular arch structure repeated to form a linear vaulted space. Vaulted roofs are popular for large halls, train sheds, green houses, and basilicas. They were originally made with brick arches, then heavy timber, then cast iron, and now with light steel or aluminum framing. Hoop houses and metal Quonset huts also create vaulted spaces. Draw a vaulted roof in axonometric and then in section.
Activity 6 – Mansard Roof
The Mansard roof originated in Paris, France when building owners added additional floors for rooftop apartments on existing buildings. The mansard roof goes by additional names- the French roof, Curb roof,etc.; it has multiple sides with many slopes in a hip style roof. The lower portion of the roof usual consists of dormers or windows with a ceiling above them. Draw a French building with a mansard roof and draw a section through the mansard roof with a dormer.
Activity 7 – Domed Roof
Domes are half and quarter spherical spaces formed by rotating arches around a central point. Some domes have an added cupola on top of the dome that lets in light in the center. Others like the Pantheon in Rome have an oculus or circular opening or eye to the sky. Domes cover special spaces in government, library and church buildings. The interior side of the dome is infilled with decreasing trapezoidal shapes that diaphragm or hold the structural ribs in place. Does your city have any domed buildings? Some domed structures have interior domes, acoustic domes, visual domes, and exterior domes, stacking them from the inside to the outside. Draw the section of the dome of the Capital Building in Washington, DC.
Activity 8 – Is there such a thing as a flat roof?
A flat roof is a roof that visually looks horizontal or parallel to the ground. Flat roofs appear in areas that have little precipitation, or in urban areas. In fact, all flat roofs are sloped to remove precipitation. They have built up roofs that drain to interior roof drains, wall drains, or exterior gutters. Flat roofs are subject to freezing and thawing of snow and ice which works against the weather seal. Over time all ‘flat roofs need to be resealed.’ Flat roofs, though, can be inhabited if structured to carry people and plants. Flat roofs in urban areas, if they do not have plants or solar panels, often serve as roof gardens, patios, and party decks. Even roofs that are not inhabited are now painted silver or white to reflect, instead of absorbing, heat. Find a high place and look out over your city. Take a picture and identify all of the roof types you see.
Activity 9 – Green Roof
A green roof is a flat or gently sloped roof that planted with native plants. Look at NEXT.cc’s Green Roof Journey and find a roof that needs a green roof! Find or design a green roof on a building you know!
Activity 10 – Solar Roof
A solar roof is a roof pitched to the south that has solar panels, photovoltaic cells, or solar shingles to collect the radiant heat from the sun and transfer it to the generation of electricity. Draw solar panels or shingles on the house you like in your neighborhood.
- Flat roofs are flat.
- A roof that has tops a building and adds additional living space is often called a
- A hip roof slopes in _____ directions
- A circle spherical roof is a
- A roof protects people from the weather.