House N:  Houses by DE FRANCA ARCHITECTURE + DESIGN

​The pros and cons of a flat-roof house

Johannes van Graan Johannes van Graan
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South Africa is prone to numerous designs and styles when it comes to residential structures, including the all-too familiar flat-roof house. But saying that a roof is 100% flat is actually inaccurate, as a flat roof usually has pitch/slant of about 15° to allow for rain drainage. 

Although the flat-roof house is a great option for those living in low-rainfall areas, one cannot deny that it also makes for a unique, modern look when it comes to visual aesthetics – definitely one of the reasons why so many people opt for a flat-roof design.

But like all things when it comes to architecture, decent research is required, which is why we’ve taken it upon ourselves to find the pros and cons of the flat-roof house.

​1. The pros of a flat roof: Usable space

Modern double storey family house:  Houses by Ndiweni Architecture
Ndiweni Architecture

Modern double storey family house

Ndiweni Architecture

Probably the biggest advantage of flat-roof structures is that they allow for more space, which would have been lost had a pitched roof been used. With a flat roof, one has the option of adding an extra floor or storey, with no slanting or angled walls to intrude on the space. 

This also makes it possible to use the extra space on smaller structures such as extensions, porches, and garages.   From the outside, a flat roof can allow for socialising/relaxation spaces like a rooftop deck or patio. And don’t forget about rooftop gardens, which are very much on trend in the 21st “green” century! 

Read moreUnique living rooms: 20 cool houses with flat roof

​2. The pros of a flat roof: Pricing

Perspectives:   by cld architects
cld architects

Perspectives

cld architects

Generally speaking, a flat-roof house is cheaper, since it requires less material for the roof. Of course this also depends on various other factors (such as the size of the house, location, etc.), but at the end of the day the reduced cost is thanks to the fact that no rafters (required for pitched roofs) are used. 

Additionally, the property’s footings are not required to be as deep as with a pitched-roof design, for flat roofs don’t place nearly the same amount of load onto the building’s foundations. 

homify hint: The insurance of roofing/building companies is generally cheaper when installing flat roofs, for it’s harder to fall off a flat roof than a pitched one!

​3. The pros of a flat roof: Additional factors

Replacement cost: The complete replacement of a flat-roof design requires much less time, thereby heavily reducing the costs. 

Quick installation: Because they lack pitch, flat roofs are easier to install. And as they lack the rafters and trusses that are used with pitched roofs, this allows for quicker installation as well.  

Compact design: Since they save on space and have excellent compact designs, flat roofs are also the popular choice for smaller structures, like extensions.

​4. The cons of a flat roof: Leakage

Those living in high-rainfall areas would be best advised to steer clear of a flat-roof house, as water on the roof builds up much quicker before soaking into the house. When a flat roof leaks, the damage often goes unnoticed for quite some time. The water first soaks through the roof, then seeps through the insulation and any structure below before it is noticed, and by then the major damage has already been done. If left for too long, this can result in: 

• A weakened roof structure 

• A total removal and replacement of the roof (if the insulation is affected), as it would end up becoming too mouldy 

• Mould sores, which can become a health risk when breathed in 

• Escalated damage costs.

5. ​The cons of a flat roof: Additional factors

Insurance: Insurance companies definitely take into account the fact that a flat-roof house is more prone to leaking. This results in raised rates for the homeowner. 

Heat absorption: A flat roof is designed to absorb heat. Because there is no roof pitch, the entire surface is exposed to the sun all day long. And although this sounds like a great idea for winter, the winter sun is at the lowest point; thus, there is a minimal amount of sun compared to the summer months, when your home will receive a full-on scorch from the overhead sun all day long.  

Maintenance: All roofs require regular maintenance. However, due to the nature of the slope, flat roofs often require more maintenance throughout their lifetime. Remember that, when it comes to drainage, a flat roof is not nearly as effective as a pitched one. Thus, without regular inspection, drains can become blocked, resulting in damage and leaks. 

Repairs: As a roof is exposed to the elements, it needs a waterproof seal, which must be maintained regularly to prevent leaks and expensive repairs. A lot of flat-roof leaks are due to a lack of regular inspection and maintenance, which is why, if you live in a flat-roof house, it is crucial that you make the time to regularly check your roof.

Umhlanga house 7:  Houses by bloc architects
bloc architects

Umhlanga house 7

bloc architects

At the end of the day, it is best to consult with a professional roofing contractor to determine the best roofing structure for your home and individual needs. 

Flat roofs or not, we’ve discovered 9 of the most beautiful houses in South Africa.

What are your thoughts on flat-roof houses versus pitched-roof designs?
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