The best kind of roof for a mountain house, or better said the most suitable one, is cavity-vented, insulated, A-frame, high-slope, metal roof that will be able to cope with climatic factors (that are far more present) and be durable enough (which is crucial) for facility in mountainous areas.
Of course, there are many variables that need to be determined in order to rate a roof as the best kind for a mountain house or any other house, what so ever. The above-mentioned variant is, to our opinion, the most effective, i.e. it has the best invested/obtained ratio.
Modern construction makes it possible to overcome the challenges posed to the roof of a mountain house in a number of ways. What exactly are the challenges and what are the solution options, we describe in detail below.
What are the main goals when designing the roof of a mountain house?
The main goals when designing the roof of a mountain house are dealing with:
- The falling snow and ice,
- Freezing rain,
- Sliding snow and ice,
- Water melt and icicle formation,
- Strong winds,
- Windblown snow infiltration,
- Freeze-thaw conditions,
- Obstruction of windows and skylights and
- Obstruction of driveways.
Mountain houses are situated in areas where the climate conditions are significantly different from other places. Here, we primarily mean the combined impact of large amounts of rain and snow, strong frosts and strong winds. The peculiarity is reflected in the fact that the roof must meet different requirements than usual.
In addition to the technical specifics caused by the climate, it must also be taken into consideration that the roof of a mountain house should provide a sense of uniqueness and coziness with its visual quality, because that is the most common reason for building such houses. Also, in some areas, local authorities restrict the use of roof materials, colors and shapes in order to preserve the unique ambient entirety. In such cases, the investor must abide by the rules.
Pay a special attention to the fact that the roof of a mountain house affects energy efficiency more than the roof of an ordinary one, because it covers more living space than usual.
Which roof shape to choose for a mountain house?
The best recommendation is to choose GABEL or A-FRAME.
People have been building for thousands of years in mountainous landscapes, on different continents and regions. Time has molded two basic forms that are applied everywhere and only the stylistic elements vary. The reason is that the simpler the better. Complex designs with many angles and corners disrupt the roof’s ability to shed snow. Snow tends to get bogged down at each angle it encounters.
The gable roof is the typical pitched triangular roof that you see on many houses all over the world, along with its variations (cross gable, front gable, Dutch gable, combined with dormer window, etc.). It’s probably what comes to mind when you imagine what a suburban home with the typical peaked roof lines looks like in most states.
These roofs can be constructed quickly and inexpensively. When building a regular or basic gable roof, you can use any sort of roofing material, including asphalt shingles, cedar shingles or shakes, slate, clay or concrete tiles, and more. This design makes thermal and hydro insulation cheap and easy, which increases its cost-effectiveness.
The majority of the area beneath the roof structure is suitable for residential usage. In mountainous areas, the triangular design is advantageous since it makes it easy for snow, rain, and ice to slide right off.
However, in mountainous places that frequently encounter strong winds, gable roofs might not be a good idea (depending on the pitch). This is due to the possibility of wind damage to the canopy or ridge, particularly if it has a cross gable or dormer windows.
The sharpest gable-style roof that resembles the letter A is an a-frame roof. It is a common roof design used on everything from Nordic ski chalets to tropical cottages. It typically starts at or near the foundation line and comes together in the shape of the letter A at the top.
The A-triangle frame’s shape has existed throughout history, but it really really began to gain worldwide recognition in the middle of the 1950s and continued through the 1970s. They were almost always inexpensive to construct. A-frames also started to be sold as prefabricated kits, further reducing the price. Their steep roof pitch is appropriate for windy locations, particularly when combined with an appropriate covering.
Angled right to capitalize on the sun’s trajectory, it can be a bright, beautiful, open space to inhabit.
What types of roof construction are used for a mountain house?
We can define two basic types of roof construction: vented and unvented! Roof terminology is not rigidly defined. Usages vary slightly from region to region, or from one builder or architect to another. By “type of roof construction”, we imply the way in which the wooden roof structure is insulated.
Cavity-Vented insulated pitched roof
As we’ve already mentioned, the attic is typically used as living space in mountain homes. In some situations, the assembly might be smaller and produce a pitched roof and sloped ceiling in one piece, but the same barrier and ventilation requirements still need to be taken care of. Utilizing roof framing sections that are deep enough to support the structural loads, accommodate the necessary amount of insulation in between, and still leave room for ventilation is a typical strategy.
The assembly’s inner face is where the air barrier and vapor retarder are located, while the water barrier will continue to be on the assembly’s external surface. Between the structural members, insulation is put to the desired or required level. The requirement for a continuous ventilation space of at least 2 inches in depth that permits air to flow between the soffit and ridge openings so that each framing area is ventilated will limit the depth of the insulation (not every other space as some would purport).
To ensure that ventilation space is maintained, continuous vent chutes or insulation barriers are frequently constructed along the underside of the roof sheathing.
Top-Vented insulated pitched roof
The alternative is to build an extra ventilation layer on top of the framing layer if supplying enough ventilation and insulation in one depth of framing members is not easily feasible. In this instance, rigid insulation is put over a timber frame and ceiling system, or insulation is injected into the framing cavity. Then, as a “over-roof,” a minimum 2-inch air space is given to remove any moisture that escapes up via joints in the insulation.
In order to prevent snow from melting and ice dams from developing, the ventilation area also helps keep the underside of the over-roof surface cold. When structural insulated panels (SIPS) are also utilized, the over-roof method is advised because the panel joints may allow air from inside the building to escape. This over-roof strategy works well for ventilation, but it can be more expensive to build because a ventilation channel needs to be made that supports the water barrier for the sheathing and roofing.
A top-vented insulated pitched roof includes rigid insulation with joints staggered and a 2-inch air channel to carry any moisture in the roof out through a ridge vent.
Image taken from quiktherm.com
Unvented insulated pitched roof
The insulation used in this assembly fills the whole space between the ceiling and roof sheathing and is used in a sloped roof/ceiling assembly. This can be made of rigid insulation with built-in water, vapor, and air barriers, such as closed-cell polyurethane or poly-isocyanurate, that is air impermeable (i.e., acts as an air barrier) between the inner and outer surfaces.
This could also be accomplished by spraying air-impermeable insulation all the way through the depth of the roof framework. Or, if the produced SIPS use air-impermeable insulation, they may be utilized. To provide totally continuous air, thermal, and moisture barriers in these situations, the roof system depends on the various qualities of the insulation and other components. As a result, no ventilation is required or offered.
An unvented insulated sloped roof is one that commonly uses air-impermeable insulation in all or most of the space between framing members (shown as light green color in illustration), usually in the form of spray foam insulation.
Image taken from continuingeducation.bnpmedia.com
What roof slope to choose for a mountain house?
A high-slope roof for a mountain house is a simpler and cheaper solution, although it is possible, even very efficient, to use low-slope roofs, all depending on which approach for dealing with snow you choose.
When it comes to dealing with a lot of snow, there are two fundamental rules. The best natural insulator available and also the most cost-effective is snow, thus the first step is to create a little slope in the roof structure to allow snow to remain on the roof. The old-fashioned homes in the Alps are a prime illustration (a chalet or also called Swis chalet).
This strategy offers a number of benefits. First, we benefit from snowfall. The attic space can be utilized without losing any of its size thanks to the long and gently sloping roof sides. Wide, well-supported eaves that are positioned perpendicular to the front and back of the house prevent snow from building up and obstructing skylights, windows, and roadways.
The roof’s exposed enormous beams, which are essential for the roof to have the strength needed to handle the great weight of the snow accumulation, also provide a fairy-tale ambience and a cozy feeling, which are frequently the key design requirements in such homes. Now, you undoubtedly believe that low slope is the correct response.
But wait a minute! There are neither universal answers nor right or wrong solutions. This layout also has certain shortcomings. Due to snow retention, it was said that the roof structure needed to be greatly strengthened. It implies that the walls’ structure must also be suitably fortified. Better hydro insulation is also required as a result of snow retention. All of this leads to an increase in price.
The second strategy is to keep the snow off the roof. Large snow slides are caused by higher pitches. Five pounds per square foot amount to ten inches of new snow! We eliminate that weight and allow for a lighter construction of both the roof and the house’s walls by increasing the slope of the roof.
The installation of the required hydro insulation is made simpler by improved snow removal. All of this brings down the cost! On the other hand, a slope that is really steep could cause a lot of snow and ice to fall at once. The substance could easily crush people or vehicles if it falls on them.
The blatantly slanted interior walls such pitched roofs produce are another annoyance. This makes decorating challenging. How can you effectively utilize those angled walls by hanging art or placing furniture? It is not possible to use the full attic as living space. It is more challenging to resolve problems with necessary repairs that develop over time.
What are preferred roofing materials for mountain houses?
Several different types of roofing materials can be suitable for mountain properties, and the material that is best for your house will depend on a few factors. We have previously discussed in the text the factors concerning the surface on which the covering is placed. Now, it remains to consider the physical and technical properties of the material itself.
Composite roofing products last longer, are more durable, and are much more aesthetically, and architecturally pleasing than traditional roofing materials. Composite roofing shingles are perfect for any climate or region in the world and they come in several styles including slate, cedar shake and barrel tile! Other plastic shingles can become brittle and break in freezing climates. Composite roof tile is made of compressed recycled plastics & other sustainable materials.
Clay roof tiles are an attractive and popular roofing option. Their smooth, artistic appearance can improve your home’s curb appeal and even add value if you decide to sell. They are weather-resistant and durable enough to withstand snow, rain, and heavy winds. However, clay roof tiles are some of the most expensive roofing materials on the market, and they can sometimes experience damage after a severe snowstorm or hailstorm. Clay tiles are also heavier than other roofing options, and we have already noted that weight may play an important role in roofing the mountain houses.
Metal roofing is an excellent option in terms of durability and design. It is one of the strongest roofing materials, and metal roofs can easily hold up to extreme weather conditions like rain and snow. Although metal roofing can be customized to suit your home’s design aesthetic by choosing from several metal sheeting options that imitate the look of wood or tile, as well as select your desired color choice, it is questionable whether you will like the final visual effect. Stil, this type of roofing is best suited for mountain homes that experience frequent harsh weather conditions.
A unique and modern roofing option, stone-coated steel is incredibly durable in the face of extreme weather. Steel is a sturdy roofing material on its own, but this steel is covered in a dense layer of stone to provide further protection against the elements, though stone-coated steel is a pricier roofing option. If you’re looking for the most durable roofing option for your mountain home, stone-coated steel might be the best choice for you.
Asphalt shingles are the most common roofing materials in the US, covering about 90% of homes. Though not as strong as other options, they are better suited for homes located further down the mountain and are subject to less-frequent snowstorms. They are more affordable than other premium options but still provide a decent amount of protection and durability. Impact-resistant shingles can be a solid alternative if you prefer shingles but live higher up in the mountains.
We live in a time when the sustainability of construction is a growing imperative. Therefore, we suggest that, in addition to the standard ones, you also consider ecological roofing solutions. A green roof or living roof is a roof of a building that is partially or completely covered with vegetation and a growing medium, planted over a waterproofing membrane. There are two types of green roof: intensive roofs, which are thicker, with a minimum depth of 12.8 cm (5 1⁄16 in), and can support a wider variety of plants but are heavier and require more maintenance, and extensive roofs, which are shallow, ranging in depth from 2 cm (13⁄16 in) to 12.7 cm (5 in), lighter than intensive green roofs, and require minimal maintenance.
Traditional roof coverings
In some cases, in order to achieve a visual effect or comply with local building regulations, the technical characteristics are set aside. Then, materials that are forgotten in modern construction, such as wood or straw, appear as an option for covering the roof. Such materials will require much more regular maintenance but nevertheless will not have the durability that modern materials have.
To summarize, a decision on what the slope of the roof should be, must consider the following factors:
- The falling snow and ice prediction for the location where the construction site is.
- Historical records of falling ice or freezing rain accumulations.
- Strength and direction of prevailing winds.
- Budget difference calculation and whether you are willing to pay it or not.