Converting a Pitched Roof to a Flat Roof: Everything to Know

Quebec roofers regularly convert flat roofs into pitched roofs. But did you know that the opposite is also possible?

If you’re interested in converting your pitched roof into a flat roof, keep reading! Our roofers will go over the different benefits and risks of this transformation process.

You will also learn why it’s so important to enlist professionals for this kind of job.

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Converting a pitched roof into a flat roof: a complicated process

In Quebec, converting a pitched roof into a flat roof is more than a design decision, it’s a structural and regulatory challenge. This type of transformation modifies how the building handles water, snow, and heat, which directly affects its compliance with the Building Code. Municipal regulations may also require a permit and specific drainage or load-bearing calculations. From a technical standpoint, the existing framing might need to be reinforced or entirely replaced to support the new horizontal load distribution. Insulation, vapor barriers, and slope-for-drainage must all be rethought to avoid issues like ponding water or infiltration. Without expert planning, these details can lead to costly structural problems. That’s why working with experienced roofers and structural engineers isn’t optional, it’s the only way to ensure that design, safety, and code compliance are fully aligned.

There are really only two ways to convert your pitched roof into a flat roof:

Completely replace the structure
Alter the existing structure if possible

Ideally, you would remove the entire roof structure and remodel it to build the flat roof. But there are many different things to keep in mind, including: building type, roof size, weather conditions, your budget and the type of membrane you want to install.

Flat roofs are quite different from pitched roofs and come with certain drawbacks, like:

A higher price: Flat roofs generally cost more per square foot than conventional asphalt shingles.
More upkeep: Flat roofs can cause structural problems. This is even more true for buildings located in regions where there is a lot of rain and snow, like Quebec. That’s you should have a professional inspect your flat roof at least twice a year, if not more regularly, to make sure you won’t have any major problems. Thankfully they are easier and less expensive to inspect than a pitched roof inspection because you can walk on them.

Converting a pitched roof to a flat roof: a project for the pros

Are you renovating your house and considering converting your pitched roof to a flat roof? There are several things to keep in mind.

First of all, think of the extra weight that a flat roof with a deck would add. The building structure must be sound enough to bear this load.

Flat roofs also need an efficient drainage system and a watertight roof membrane. Otherwise, your flat roof could be vulnerable to leaks.

If you dream of soaking up the sun’s rays from your very own roof deck, call a qualified roofing contractor who will work with a structural engineer to make your dream a reality.

Converting a pitched roof into a flat roof takes time, but it can increase the modern appeal and value of your home. However, it’s important to find the best professionals for the job to ensure long-term durability and proper structure. While the initial costs may seem high, a well-designed flat roof can lower maintenance costs over the long run by being easier to inspect and more accessible to repair.

If done well, this transformation can open up opportunities for rooftop living spaces while preserving structural integrity. Always work with experts who understand how to balance design and function over time, ensuring your investment pays off.

4 advantages of converting a pitched roof to a flat roof

In Quebec, flat roofs are common on commercial and apartment buildings, especially in urban areas.

In recent decades, more and more single-family homes have been built with flat roofs thanks in part to the many advantages they have over pitched roofs, including:

A unique aesthetic
More living space on the roof
More light inside your home
A safer, more accessible roof

1. A unique aesthetic

A flat roof gives a building a distinctive look. Flat roofs on houses have the clean, modern aesthetic that many property owners prize. They make buildings look angular and solid without adding bulk.

The roof covering on a house with a pitched roof is clearly visible and is a part of the house’s design. Flat roof coverings, on the other hand, are often invisible from the street.

Converting a pitched roof to a flat roof will therefore dramatically change the house’s appearance.

2. More living space on the roof

A flat roof can provide inhabitants with more living space. For example, it may be possible to create a patio or green space on a flat roof, provided that its structure and decking are suitable.

A homeowner could take advantage of their flat roof conversion project to redesign the attic and the upstairs rooms. These are costly, major renovations, but they can create a lot more living space.

3. More light inside your home

A flat roof often creates more light inside the house. Flat roofs are perfect for installing skylights, which fill rooms with natural light.

When converting a pitched roof to a flat roof, it may be possible to replace the dormers with large windows to let in as much light as possible. Of course, this would require a major redesign of the upper levels.

4. A safer, more accessible roof

Maintenance and snow removal on a pitched roof can present safety hazards for those doing the work, especially if they do not have the right equipment or experience.

A flat roof also requires rigorous upkeep, especially to prevent snow build-up and water infiltration. On the other hand, the risk of falling off a flat roof is very low, especially if proper safety and prevention measures are taken.

Additional considerations when converting pitched roofs to flat roofs

When evaluating whether to transform a pitched roof into a flat roof, it is important to look beyond the immediate aesthetic change and consider the additional technical and financial implications. While the benefits of flat roofs are attractive, such as modern style and the possibility of creating new outdoor spaces, the long-term costs can vary depending on your choice of materials and construction method. For example, membranes and protective coatings are generally more expensive than asphalt tiles, but they provide better durability and resistance to infiltration.

Flat roofs also change the way a property consumes and conserves energy. A well-insulated flat roof can reduce heat loss in winter and limit overheating in summer. In Quebec, where seasonal temperature swings are extreme, this aspect can have a major impact on your heating and cooling bills. Choosing eco-efficient materials or even green roof systems can further optimize performance.

Structural support is another essential factor. A flat roof distributes weight differently than a pitched roof, which means reinforcements may be required to handle snow loads or to fill additional capacity if you plan to install a deck or rooftop garden. Always verify local regulations and obtain the necessary permits, as municipalities often impose requirements regarding drainage systems and slope-for-drainage even on flat roofs.

If you are uncertain about whether the pitch of your current structure can be altered safely, the best approach is to consult experts and request a detailed assessment. A professional roofer will not only explain the options but also reply to your concerns with tailored solutions that balance design, function, and budget.

Ready to enjoy the benefits of a flat roof? Contact Les Couvreurs Duro-Toit

In short: converting a pitched roof to a flat roof comes with many advantages.

Are you looking for a company that can handle major roofing work? Les Couvreurs Duro-Toit can get the job done safely and in compliance with building codes. As for the quality of our work, we come recommended by CAA Habitation and have been the consumers’ choice two years in a row.

Our specialists are prepared to tackle any and all of your project needs. Contact us for a quote!