Technical Talk: A solid case for slate roofing

2019-10-04T09:26:33+00:00October 4th, 2019|Features|

We caught up with slate roofing specialists Perfect Slate to discuss what makes this hardy building method one of the highest quality, longer lasting roofing materials on the market.

By Candace Sofianos King

Slate is a prestigious roofing material namely due to the fact that its harvested from nature, believes Bambo Shongwe, MD of Perfect Slate, a Johannesburg-based state-of-the-art slate roofing specialist company, which prides itself on excellence in the supply and installation of natural slate tile roofs, concrete tile roofs, IBR, corrugated, Chromadek, Nu-Tech slate roof covering, waterproofing and roof repairs.

Shongwe highlights that currently there is an increase in demand for slate roofs, namely among high-end estates that are starting to prescribe slate roofs to their developments. Relatively available from local quarries, Shongwe notes that Perfect Slate sources its slate from the mining belt of North West Province.

Although easy to acquire, the price of slate is quite a hefty one, says Shongwe. “Slate’s one real disadvantage is its price tag, however, in the long term it’s economically viable,” he says, adding that builders and property owners are spoilt for choice when it comes to the colour variety available which is dictated by price.

“Slate is available in different colours and variants such as silver blue, multi-colour, African blue / matte black, as well as old / west-country. The choice of colour depends on the architectural preference,” Shongwe highlights.

Slate installation

Slate is generally fixed by means of two different methods: conventional and Alumaz – both have their pros and cons. For the conventional ‘old’ slate system, the slate is fixed on roof pitches of 30 degrees and higher. A triple layer of slate is used with an underlay only on the ridges and hips. This system of roof will last longer than the Alumaz, or Peterlo, roofing system, as there is no underlay on 90% of the roof.

The Alumaz slate system is installed on roof pitches between 17 and 30 degrees. The main benefit of this system is that it has a composite waterproofing membrane between the layers of slate. Even if you have broken slate, the roof will not leak, as the underlay waterproofs the roof. The underlay, however, should not be left exposed for too long, as it is costly to replace.

Slate roof maintenance

Slate roofs need to be repaired and maintained regularly, this usually involves changing broken slate tiles, inspection and repairs of ridges, hips and valleys since the underfelt is prone to perish after several years, resulting in roof leaks.

“Slate has a high maintenance rate and should be serviced once a year due to acute weather conditions as well as thermal shock. Ridges and hips form the weakest points on a slate roof and it is imperative to inspect and repair them with every roof maintenance,” Shongwe explains.

He adds, “It is an obligatory requirement from insurance companies that homeowners and industry professionals should commission a reputable company to maintain their slate roof on an annual basis.”

Perfect Slate variations

  • Silver blue: A cool and rich grey with blue and black undertones. Easily accessible in South Africa, this slate is more cost effective compared to other slate tiles.
  • Multi-colour: Featuring a rich mix of greys, golds, browns and hints of blues, this slate is not easily available and costs more than the other tiles. It is also available in a variety of sizes.
  • African blue / matte black: An excellent choice, this fine-grained material consists of quartz, mica, chlorite and calcite. The slightly uneven surface of a natural stone tile gives each piece its own characteristics.
  • Old / west-country: Slate splits naturally along planes, revealing pallets of vivid colour not seen in stone with processed surfaces. The topography of the surface is intricate and boasts character, depth and grain. This type is designed to complement the inherent beauty in French and Tudor architectural styles. Available in a broad range of colours, it faithfully captures the appearance of natural slate.

The perfect solution

Perfect Slate offers various slate tile services including:

  • New slate tile supplies
  • Installation on new slate roofs
  • Slate tile repairs
  • Maintenance contracts at a fixed rate a year