Page "Roof" Paragraph 26

Slate is an ideal, and durable material, while in the Swiss Alps roofs are made from huge slabs of stone, several inches thick.

The slate roof is often considered the best type of roofing.

A slate roof may last 75 to 150 years, and even longer.

However, slate roofs are often expensive to install – in the USA, for example, a slate roof may have the same cost as the rest of the house.

Often, the first part of a slate roof to fail is the fixing nails ; they corrode, allowing the slates to slip.

In the UK, this condition is known as " nail sickness ".

Because of this problem, fixing nails made of stainless steel or copper are recommended, and even these must be protected from the weather.