Q.
(a) Pitch roof vs flat roof
Refer to 2013 Q5 on factors affecting choice of roof structure.
We are situated in a path of tropical monsoon, we are blessed with lots of rain fall. Hence, the roof construction must take the volume of water as a major consideration. Roof must have the gradient to allow rain water to drain off as to reduce live load to the roof. Pitched roof has this function but not flat roof.
Flat roof does not have the gradient to allow rain water to quickly run off the roof. This will accumulate on the roof and increase the load the roof structure has to carry.
Wikipedia has the standard form of flat roof as below:
A flat roof is a roof which is almost level in contrast to the many types of sloped roofs. The slope of a roof is properly known as its pitch and flat roofs have up to approximately 10°.[1] Flat roofs are an ancient form mostly used in arid climates and allow the roof space to be used as a living space or a living roof. Flat roofs, or "low-slope" roofs, are also commonly found on commercial buildings throughout the world. The National Roofing Contractors Association defines a low-slope roof as having a slope of 3-in-12 or less.[2]
Flat roofs exist all over the world and each area has its own tradition or preference for materials used. In warmer climates, where there is less rainfall and freezing is unlikely to occur, many flat roofs are simply built of masonry or concrete and this is good at keeping out the heat of the sun and cheap and easy to build where timber is not readily available. In areas where the roof could become saturated by rain and leak, or where water soaked into the brickwork could freeze to ice and thus lead to 'blowing' (breaking up of the mortar/brickwork/concrete by the expansion of ice as it forms) these roofs are not suitable. Flat roofs are characteristic of the Egyptian, Persian, and Arabian styles of architecture.[3]
Wikipedia search 'flat roof', available at
Why pitched roof is better?
Other than installation costs, there are numerous benefits a pitched roof can offer compared the more standard flat roof. Homeowners may not think about their roof often, but it plays a key role in the home’s value and future expenditures. A pitched roof not only looks prettier to potential buyers or neighbors driving by, but it offers many other advantages. Below are five key benefits of pitched roofs.
Although pitched roofs are more expensive to install, repairing a flat roof, as in 5 Things To Know Before Fixing Your Roof, can cost significantly more than a pitched roof and as a result, the investment in a pitched roof can be the smart play. Like every other aspect of the home, whether it’s your HVAC, kitchen counters or toilet, products start to wear and the roof, especially since it is exposed to natural weather 24/7, can wear pretty fast. Fortunately, the materials used for pitched roofs tend to be more durable and weather resistant. Therefore, a pitched roof is usually more affordable in the long-term.
Tip: Do not get held up on the initial costs of any home investment. Just because a product is more expensive now, it does not mean the repairs will be less expensive later on. Current and future expenditures must be taken into account before any home improvement project.
Steep Roofs React Better to Inclement Weather
If you think of basic geometry, a flat roof receives a much bigger hit to inclement weather versus a pitched roof. It is why, more often than not, you see very steep roofs in areas of America that see lots of rain and snow. However, very shallow roofs can be considered pitched as well. You can measure your roof pitch by viewing our roof pitch calculator.
The reason pitched roofs are better in rain is due to the drainage system. Flat roof drainage is not as effective as a pitched roofs and without regular inspection, drains can become clogged, leading to damage and leaks. Remember, going back to benefit No. 1, flat roof repairs are more expensive than pitched roofs. Why not ignore this hassle all together by installing a pitched roof?
Tip: If you are already thinking about altering your current roof, see how to Convert A Flat Roof to A Pitch Roof.
Pitched Roofs are Easier to Inspect from Ground Level
Hopefully, you were convinced after reading What to Know About Roof Installation that you need to constantly monitor and inspect your roof. Finding problems before they become huge issues will save you a boatload of money. Damage that goes unattended for too long can result in extensive water and ice damage inside an attic or around the flashing that separates structural roofing materials from skylights, chimneys and other fixtures.
While inspecting a pitched roof, homeowners must realize that the surface is more difficult to hold a balance compared to a flat roof. If you do not feel comfortable walking around a pitched roof as you inspect every inch, try inspecting it from your front and backyards. Given that your roof is sloped, you should be able to see a good portion of your roof. There is no shame in taking a pair of binoculars and looking from the ground.
For more tips on proper roof monitoring, check out a full article on New Roof Inspection.
You Can Add An Attic to A Pitched Roof
As I am sure many homeowners can agree, everyone could be more organized. Well, a terrific way to declutter your home is by adding an attic. Most pithed roofs allow for plenty of room to add an attic or loft space. Many homeowners use this existing space for storage, but if need be, homeowners can convert this unused area for an extra bedroom or office, like the example below.
So if you are thinking about installing a new roof and want some extra storage or living space, go with a pitched roof.
Numerous Materials to Choose
As you briefly saw in What to Know About Roof Installation, whether you decide to go with a pitched roof or a flat roof, you will have many materials to choose from. Shingles make up the most popular choice among U.S. citizens, but there are many other forms a pitched roof can take:
Pitched Roof Materials
- Composition Shingles
- Dimensional Shingles
- Asphalt Shingles
- Wood Shingle
- Concrete
- Tile
Ref:
Pitched Roofing - Advantages
Loft Space
Pitched roofs, which have at least two slopes that rise to meet at a peak, are constructed in such a way as to afford plenty of usable space in the loft area, either as much-needed storage or even as additional living space, such as a study or playroom. In the process of designing the roof, any planned usage of this area can be incorporated into the plans so this type of roof offers an unmatched flexibility that a flat roof cannot.
The pitched roof, if constructed properly, is almost certain to offer a much longer lifespan than a flat roof, with materials that are more durable and weather resistant. The internal accommodation will be more efficiently insulated and will not suffer from the extremes of temperature that tend to afflict rooms under flat roofs.
Installing a pitched roof also means the building can be more effectively blended in to either the rest of the property (in the case of an extension) or to neighbouring buildings, while also helping to retain a sense of individuality and character.
Pitched Roofing – Disadvantages
Expense
Unfortunately one consequence of this is the increased expense, as the more complex design, additional building materials and extra man-hours cost significantly more than a flat roof.
Pitched roofs also place a greater burden on the foundations of the building and this may have implications for the depth of the footings. Replacing a flat roof with a pitched roof on an existing structure is therefore not always feasible.