Flat Roof House: (Pros and Cons) Plus, 3 Types Explained

A flat roof house, or low-slope roof, is when the roofs are even opposed to raised or inclined surfaces. They are a departure from the norm because most houses have sloped roofs.

Flat doesn’t mean entirely flat, though. Instead, some degree of inclination is given for water drainage purposes. Flat roofs can have a slight slope of 1/4th of an inch on every foot. 

Think flat roof homes, and we’re sure the very first thing to come to mind was the luxury homes of the wealthy businessmen, movie stars, and politicians during the middle of the century post the second world war. Many architects experimented with flat rooflines, and the results were quite stunning. 

flat roof house pros and cons

Why did flat roofs become so popular during the 1900s?

A flat roof is one of the most sought-after options that started at the turn of the 20th century. The cubic structure buildings were much sought after for aesthetic reasons, but that is not the only reason. Apart from looking rather novel and simply less common (don’t we all want our homes or office spaces to be slightly different from the buildings surrounding it)?

One of the major reasons for their surge in popularity was that the occupants of that building get to save a lot of space.

Consider this: as opposed to a Gable Roof, Gambrel roof, Hip Roof, or Shed Roof, all of which occupy a lot of space, going for flat rooftops can help the occupants save space. Flat roofs can be seen as extensions of the living space in which you live. These roofs can are used as terraces and circulation areas. 

All this, of course, is only when there were enough resources and technical knowledge to know how to construct flat roofs in the first place. Generally, you can find flat roof buildings in countries where the temperature is warm or hot instead of countries where the climates are a lot colder, where it snows often, or where frequent rainfall is a common phenomenon.

The reason? Think of this. If the rainfall in a particular region is scarce, then the materials available for constructing roofs (be it wood, slate, metals, asphalt, clay, and transparent materials like glass) and buildings will also be less. Therefore, flat roofs require fewer resources for the construction of the roofs as opposed to the other more complex roof structures.

Flat roofs combine design aesthetics and a lot less labor and resources. However, you may have guessed that flat roofs come with a set of drawbacks, even in the present times with all the advancements in technology, innovation in archaeology, and skilled labor.

Let’s look more into them along with their appeal in the following section.

Flat Roof House: Pros and Cons

Advantages of Flat Roof Houses

Additional Space: Flat roofs use additional living space right on the roof. This space can be used for installing an extra room, or a patio, perhaps even a roof garden. If you have always dreamt of owning a penthouse, you can install your own right atop your home when you go with flat roofing.

You could even get more creative and add a gym, perhaps a reading nook for yourself, a children’s room, or a gazebo if you are so inclined. You can use flat roofs as an area of entertainment and relaxation. You can set up your lounge to gaze at the skyline or maybe have a barbeque with your close friends and loved ones. The options are virtually endless. Only the sky (sorry, roof) is the limit to your creativity!

Moreover, you can install an HVAC (Heating, Ventilation, Air Conditioning) unit to set the room temperature to your convenience.

Energy efficiency: Want to make your living space more energy efficient? You can very well set up solar panels and make your entire living space more energy efficient. You will feel the benefits of these, particularly during the warmer or summer months. Sloped roofs tend to trap warmer air (ugh, who wants that!), or they may even allow the cooled air to escape rather than let them in. But no such air stagnation happens in flat roofs, and this just helps enhance the energy efficiency and keep your home utility costs very manageable.

Cost-effective: Flat roofs are more cost-effective. The reason flat roofs cost way less money is due to a host of reasons.

  • Installation: Installing the flat roof is super affordable. It can be done a lot quicker and easier than other complex roof structures, which makes labor costs also a lot cheaper. Another reason why labor cost is less is that there is not much risk involved setting up flat roofs. Can you imagine the installation guy falling off a flat roof? No, right? Yeah, that’s another reason why they charge you less.
  • Materials used: Another reason they cost so less – the flat roof insulation board is about 80 cents per foot- is because the materials used in the manufacture of flat roofs are also cheaper. We admit material cost depends on where your property is located and how big your house is. 

But there is no denying that there is reduced cost, primarily because there is no need for rafters (yes, pitched roofs require these). As opposed to pitched roofs, the load is placed on flat roofs on the foundation of your building because the footings are not required to be as deep.

  • Installation of solar panels will help you consume less energy. Lower electricity consumption means less cost in the long run.
  • Flat roofs don’t get damaged very easily (if properly maintained). You can save up on a lot of repair costs over the entire lifetime of the roof. So, take good care of them, and you can enjoy years of beauty because it lifts the overall aesthetic appeal of your living space. Forget about repair costs. Even if you want to completely replace them, they will be very easy, quick, and consequently affordable
  • Easier to access and maintain: Getting on top to either install, inspect, replace, or repair flat roofs is rather effortless. Maintaining involves checking the slidings, perhaps patching a hole, cleaning the gutters, and so much more. All of these can be done very easily on flat roofs.

Aesthetic appeal: There is no denying that flat roofs just make your property look so posh! They are a thing now and so contemporary. We’re sure you will be the envy of the neighborhood (if done right)! You could even try something innovative and get windows installed in the ceiling. This way, you will enjoy the dual benefits of a very novel interior design. They would look so cool to look up when you are working or lounging on the sofa indoors! And who wouldn’t all that natural light from the ceiling inside your home!

You can lift the architectural and overall aesthetic appeal of flat roofs when you go with flat roofs.

If you have opted for flat roofs for your home, you must know that it comes with disadvantages as well. 

Disadvantages of a Flat Roof House 

Leakage: One of the major cons of using flat roofs is that you have to deal with leakage issues. Flat roofs will have problems shedding water and snow, particularly during the winter months. When you compare them to pitched roofing, they may require more regular inspections because you may have to drain water more often. 

The snow may accumulate in larger volumes and must be cleaned regularly with your hands. You should have a proper drain system in place. Now, we admit that no matter what roofing you go with, they all require constant monitoring and maintenance. 

But the very nature of flat roofs calls for keeping tabs on the integrity of the roof, such as inspecting the insulator layers, drain system, and gutters to ensure that they are at the top of the drainage game. Otherwise, the drain could get clogged with time, resulting in leaks and damage to your roof. 

When it comes to ease of installation, there is nothing to beat how easily and efficiently flat roofs can be installed. But they are high maintenance. So, imagine how much more difficult it would be to maintain it if there are a lot of people in your house walking over it. And don’t get us started on kids stomping and running over it every day!

And while a roof garden sounds great, take care to see what plants you put up. Some invasive plants could just add to the leakage issue.

If your house or office space for which you want to put up a flat roof is a place where it tends to rain a lot of snow often, you MUST ask your roof contractor to install 

Don’t last as long as traditional roofs: The average lifespan of flat roofs is only around 10 to 15 years. They can be made to last longer, of course, but that just requires more effort, more maintenance, more work, and perhaps even more cost for you! 

Roof repairs costs: As we already discussed in the above section, if serious damage is caused to your flat roof, and you need to carry out repairs, then this could cost a lot of money for you. 

Not many material options: One of the most exciting things about building your new house or remodeling your house is to choose what type of roofing you will go with, its color, material, etc. But if you choose to go with flat roofs for your home, you will have very few options because a flat roof system supports fewer materials.

Flat roofs support the following materials: bitumen, TPO, Thermoplastic Polyolefin, EPOM, and rubber. Majorly, metal and rubber are the two options that go into finishing a flat roof. 

Shingles are not a great option because they would just reduce the lifespan of the flat roof. Why? They would lead to water soaking up and cause leakage issues. 

Less space for insulation: When you go with flat roofs for your building, there will be less space for insulation. Consequently, your home will be prone to be affected by extreme weather conditions.

Lower stability: Buildings with flat roofs are less stable. They have to stand up to not just the weight of the people walking over them, but they have to withstand the snow that gets built up during the winter. The lower weight withstanding capability of flat roofs means your builder may have to strengthen the building elsewhere.

3 Types of Flat Roof Houses

  1. BUR(Built-Up Roof)

Even before modified bitumen and membrane roofing came to the far, BUR (Built-Up Roofing) gained widespread popularity. They are made with hot tar and gravel. Built-Up roofing is affordable, but they are not all that common when it comes to roofing for houses.

For one, it is heavy and thick, and for another, it will give off strong odors and create quite some mess during the installation process. And that strong smell that comes off is nothing but molten tar. 

Since Built-Up Roofing is ballasted with rock, they are super thick and heavy, and this just puts so much pressure and stress on your building’s roof structure. Once the lifespan of this roofing is over, tearing off the roofs and then getting them replaced would require even more cost for you.

BUR roofing consists of a minimum of three layers, sometimes even more. These layers are nothing but waterproof ply sheets sandwiched between layers of hot tar, ballasted by a layer of smooth river stone or gravel. These days even fiberglass materials are used in the place of tar.

What you get is a tough and thick seamless roof assembly that is resistant to damage. Stability and durability are the best aspects of a Built-Up Roofing System. Another awesome thing about using BUR is that built-up roofs have a higher fire rating. This is thanks to the use of gravel which is fire-retardant roofing material

2. Modified Bitumen Roof

It was developed in the early 1960s, modified bitumen roofing (MBR) was considered a lighter-weight alternative to BUR. Unlike BUR, they are neither messy nor smelly. 

Modified bitumen roofing is made with a single layer of adhesive roofing material, and so it can accommodate DIY installations. Self-adhesive versions of modified bitumen can be installed by peeling and then sticking. 

Just like traditional asphalt shingles, modified bitumen roofing is a flexible, asphalt-based material with a mineral top coating. 3 foot wide and 36 foot long rolled sheets are rolled onto the roof over a base sheet membrane.

Earlier, though, modified bitumen roofs were installed using a torch. So, what exactly is a torch? Torch-down means heating the backside of the roofing during the unrolling process, melting the material to the base layer.

Modified bitumen roofs are light in color, and therefore the sun’s infrared rays will be reflected away. This will reduce the overall HVAC costs.

The one major drawback with using modified bitumen is that the torching method is an invitation for a fire hazard. So, they are not as safe as BUR when it comes to the fire safety factor.

Moreover, modified bitumen is not as durable as BUR either. So, if there is a lot of foot traffic in your commercial or residential property, you can expect some tears and scuffs over time.

3. Rubber Membrane Roof or Single-Ply Roofing

There are plenty of membrane roofing materials. Of these, rubber and plastic are the most commonly used ones. However, rubber has always enjoyed great popularity as a flat roofing material.

Rubber roof membrane or EPDM (ethylene propylene diene monomer) is commonly used for residential flat roofing. Now, this is a true rubber that can either be held in place with fasteners, glued, or ballasted with stone. They can also be loose-laid and then held in place with options like river rock, pavers, or even ballast.

The advantage of the rubber membrane is that leaks in the roofs can be repaired easily. Also, should any repair happen, the costs will be low because the materials to repair this will be available at a lower cost.

Lightweight and more durable than both BUR and Modified Bitumen Roof, these are a great option. However, they are not as durable as modern PVC membranes. 

Although the design is such that they resemble an inner tube, it can resist damage caused due to sunlight. PVC is highly recyclable. EPDM is a rubber material that is just as highly recyclable. Rubber roofs are naturally dark in color, and so they tend to absorb a lot of heat. If you live in a place where you experience a lot of warm summer months, you will do well to go with light-colored roof coatings. This will only increase the cost of installation. 

Conclusion

Choosing between different types of roofs can be both a challenging and exciting task. You have to consider the material, cost, durability, maintenance issues, safety issues, how easy or difficult they are to install, repair, replace, and the labor costs involved. 

Weighing all the pros against the cons before zeroing in on one that suits your property and taste makes sense. We hope this article will come in handy so that you make an informed choice in selecting one that suits your particular requirements. Good luck!

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