Reduction Of Building Costs Through The Choice Of Roof Design – Low-Pitched Vs High-Pitched Roofs

I would like to discuss the issue of choosing between low-pitched and high pitched roofs and ultimately, how this can affect building costs for a project.

The Meaning of Roof Pitch

First, the pitch of a roof can be referred to as a measure of the degree of steepness or slope of a roof. The pitch of a roof is usually measured in degrees. Based on this definition, there are three (3) categories of roofs:

• Low pitched roof – the pitch is between 8 -15˚ (pictures attached)
• High pitched roof – the pitch is between 15 -70˚(photos attached)
• Flat roof – the pitch is less than 8˚

Low-Pitched Vs. High-Pitched?

I would like to limit this discourse to low pitched and high pitched roofs only. Over the years, I have noticed that people make their preferences for low pitched and high pitched roofs for various reasons. Those who prefer high-pitched roofs to low-pitched roofs do so for the following reasons:

• Aesthetic appeal – High-pitched roofs are always visible and look beautiful, whereas low-pitched roofs are barely visible and are most times hidden behind a parapet wall or gable wall.
• Ease of water/snow runoff – High-pitched roofs will allow for easy runoff of water and snow when compared to a low-pitched roof.
• Creation of additional usable space – High-pitched roofs allow for additional rooms/storage spaces within the roof, over and above the spaces already created in the floors of the building, which is almost impossible in a low-pitched roof.

Those who prefer low-pitched roofs do so for the following reasons:

• Costs – A low-pitched roof could be 2-3 times cheaper than a high-pitched roof placed on two buildings of the same size or foot print, depending on the degree of slope.
• Simplicity – A low-pitched roof could be hidden behind a parapet wall such that the building may look ‘roof-less’, thus giving it a simplistic look. This, reason, of course is subjective.

Architects would 95% of the time go for either low or high pitched roofs due to their design philosophies. The choice of low pitched or high pitched roofs is also determined by the kind of roof covering to be used…for example, roof tile coverings like shingles require a high pitched roof structure design when compared with low-pitched, because shingles require a steep slope to effectively drain rainwater and snow due to the fact that they are fixed at short intervals; if they are used on a low-pitched roof, they will retain water/snow on a greater scale and gradually lead to leakages.
As a regular practice here in Nigeria, most low-pitched roofs are covered with long span aluminium roof covering or its variants (step tile, metcoppo, etc). The choice of a pitched roof also depends greatly on the architectural concept itself.

Final Analysis

In the final analysis, the choice between low-pitched and high-pitched roofs depends majorly on the designer, the building to be designed, and in some cases, the client. However, from a cost perspective, low-pitched roofs are far better and cost-effective in the sense that they save the client a lot of costs.
A typical high-pitched roof (see attached pictures) could cost about N5, 000,000 – N8, 000,000.00 (Nigerian Naira) for both timber carcass and roof covering, whereas a low-pitched roof constructed on the same building could cost as low as N2,500,000.00 – N3,000,000.00 (carcass and covering), based on current market prices.

Thus, for projects in which cost-savings and value for money is vital to the progress and completion of the projects, the low-pitched roof is surely the best bet and vice-versa.

I hope this will inform your design decision when you engage an architect to make a design for your next project.