5. Performance

Shale is a durable material, thanks to its mineral composition. If there is sufficient overlap between each slate and the fasteners are in good condition, the installation provides a reliable seal.

The weight of the slate contributes to the roof's resistance to tearing. This type of roofing is used on attic spaces that provide a certain amount of thermal and acoustic protection, but this buffer space must be complemented by insulation for inhabited spaces.

The main causes of ageing are wood pegs and iron nails, which rust and eventually break.

Poor-quality slates sometimes disintegrate, allowing moisture to penetrate and degrade the sheathing and woodwork.

This type of roof requires regular maintenance: re-slating slates, cleaning leaves, moss and lichen that can retain moisture and impede...