Roofing 101: What you need to know

Bian Obagiwa (left) and Edward Gitonga roll-forming sheets at Mabati Yetu Factory on October 26, 2022. [Silas Otieno, Standard]

Before you notice any other decor on a house, the roof is likely to have grabbed your attention first.

From afar, you have already decided if the house is beautiful based on the roof design and colour.

Other aesthetics follow and if they are disappointing, they will probably be vindicated by an appealing roof.

Ken Juma, the projects lead at Embakasi-based Mabati Yetu Factory, equates a house's roof to a lady's hairstyle. If the hairstyle is attractive and looks expensive, it accentuates the beauty of the woman. The opposite is also true.

Mabati Yetu makes, and sells roofing sheets - matte finish (rougher feel) and stone-coated tiles and shingles (commonly known as decra tiles, which are mainly bought by high-end customers).

It does not deal in Aluzinc, the conventional galvanised roofing sheets, and glossy finish roofing sheets which, he says, are often quick to discolour.

What about roofing sheets? Does he feel people should know? He explains to Real Estate.

How are roofing sheets made?

Local manufacturers import pre-coated steel coils, often from Uganda, Egypt, China, Saudi Arabia, or South Korea. These come with a certificate of conformance to prove they conform to local standards. They are taken through roll-forming machines that shape them to the desired profiles.

What are these roof profiles?

The designs that are common in the market include the Romax, Z-Max, Brickmax and Euromax roof tiles and corrugated (S-Max) and Boxmax profiles. Many homeowners and developers prefer the four tile profiles which he calls "innovative, futuristic, stylish, strong and durable". These products are pre-coated using advanced heat fusion technology to increase durability.

Why iron roof over concrete?

Lately, many people have gone for open-roof terraces where they slap a concrete slab as their roofs. It is seen as a cost-effective roofing method, and for many, a durable one that can be multi-purpose (families can sit for dinner on the roof). But according to Mr Juma, these create challenges in rainwater collection. The process of rainwater treatment, where it is collected off the concrete and in gutters, is more rigorous. Further, depending on taste, concrete roofing might not be as eye-catching as a nicely done, and installed, roof.

Mabati Yetu provides translucent roofing sheets which light up the building and allow for a reduction of energy use, especially during the day when the sun is out. Concrete does not allow for this.

The roofs also provide proper heat insulation for the houses they are fitted on (as compared to traditional Aluzinc which traps a lot of heat) and also filter out the noise especially when it rains.

Steel or wooden trusses?

The use of steel encourages the preservation of trees and thus is an environmentally friendly practice. Steel trusses are green, economical, and faster to install, and they do not get attacked by termites. They are thus durable. Light gauge steel frames are lightweight, and faster to install, he says. Also, all the products that cannot go into the market in such a factory (or waste materials) are recycled to make other metallic goods.

What should customers look out for?

Wily resellers take advantage of a price-sensitive market to sell roofing sheets cheaply while cunningly slashing down the size of the sheets.

But customers often fail to realise this as they are keen on rushing for the lower, rather pocket-friendly prices. These prices could be reduced for as much as 30 per cent by the resellers, at the expense of quality, and often, length.

Resellers are spread across the country, Mr Juma says. Some have physical showrooms but the majority rely on social media, mainly Facebook. They take orders from clients but decide where to source roofing sheets with special emphasis on price.

Customers should also look out for a stamp on the roofs that contains the name of the factory, the type of sheet profile, the sheet's gauge (thickness), and the date of manufacture. Lack of these details, says Mr Juma, is a red flag.

What are the advantages of direct purchase from a manufacturer?

Customers get customised roofing sheets. They submit their house plans and the computer auto-generates the roof structure. The frames are also auto-generated. This customisation means there is a reduction of wastage by up 20 per cent to 30 per cent. The company also has to do a dummy roof in the factory to see how the roof fits and if any adjustments are needed. Physical factories also give the customers security. If they have a problem with the product, they can always launch their complaints here.

Other perks include free deliveries and add-ons such as roofing nails for huge purchases. "The physical locations, Kenya Bureau of Standards (Kebs) certificates and duly registered trademarks, and the fact that majority of these factories offer free transport, flexible payment options, customisation, and warranties that are easily traceable to a factory, are essential for the buyer," he says.

How are colours added to the roofing sheets?

The steel coils come pre-coated, and in different colours. Many Kenyans seem to love charcoal grey, chocolate, tile red and brick red roofing sheets.

But some industry players splash a dash of coat on these roofing sheets themselves and try to dupe the buyers into believing they were pre-coated.

How are roofing sheets maintained?

Roofing sheets should be cleaned regularly and any unwanted material landing on them, including leaves from trees around, eliminated.

So should be the gutters that collect rain or the valleys (the also collect rainfall between two converging roofs). Lack of this leads to blockage of drainage pipes or collection of dirty water altogether.

How much do these roofs cost?

For stone-coated tiles, commonly referred to as decra, prices per piece range between Sh750 to Sh950, depending on quality and origin, Mr Juma says.

The one on the higher end of pricing is premium. The matte finish is priced depending on the gauge.

It is sold at between Sh600 to Sh650 per metre for gauge 30 and between Sh700 to Sh780 for gauge 28.

There is also gauge 32 for residential buildings and gauge 26 for long-span roofing, he says.