SSQ Del Prado Spanish Slate 500x250mm

SSQ Del Prado Natural Spanish Roof Slate

SSQ Del Prado is a high-quality hand-split Spanish roofing slate consisting of a stunning deep blue-black colour coupled with a deep texture to add an air of elegance to any roof. These slates are unfading even on a sun-facing roof.

SSQ Prado slates have a very minimal amount of inert mineral deposits within the slate and carries SSQs Rust-free guarantee, the only company in the industry to offer this.

SSQ are so confident with the quality of these slates they are covered with a 75-year guarantee.

These slates have gone through rigorous testing in accordance with BS EN12326 as well as Norm Franois NF 228 (one of the most rigorous slate testing criteria in the world). As part of NF 228, Del Prado pallets are inspected, certified and subject to independent random spot checks to ensure the slate is of the best quality.

As part of the BS EN12326 a range of attributes are tested, including the 3 most critical areas:

Water Absorption (until recently referred to as)

Poor quality natural slates are vulnerable to cracking in cold weather as they absorb excessive water. Higher quality slates absorb less water and are therefore less vulnerable to cracking. The best natural slates are classified as W1.

To reach a standard of W1 slates must absorb <0.06% of their mass in water. The SSQ Del Prado easily surpasses this high standard and achieves the W1 grade.

Terminal Cycle

Poor quality slate often contains metallic inclusions (sometimes called pyrites) that rust or oxidise. Oxidisation within slate can cause unsightly rust streaks, and in the worst cases, may weaken the slate, potentially leaving the roof susceptible to water penetration. Higher quality slates contain fewer inclusions (pyrite) which do not rust or oxidise.

Within BS EN 12326 the Thermal Cycle test grades a slate on three levels:

The highest grade where testing reveals no change in the slate, or very slight rusting that the flecks of inclusions on the surface of the slate. T1 slates will not suffer from runs of discolouration or structural weakening because of minerals oxidising.

The second grade where oxidation causes highly visible changes of the metallic inclusions with the slate. There is no structural change with the slate but runs of discolouration are likely.

The lowest grade of slate where oxidation within metallic inclusions penetrates the slate comprising structure and risk holes forming on the slate.

All SSQ slates reach the highest level of T1 with Del Prado's added Rust-Free Guarantee as an extra level of quality and peace of mind.

Sulphur Dioxide Exposure

Poorer quality slates are less able to resist pollutants in the air and degrade/soften due to the chemical disintegration of the slates carbonate content.

Under BS EN 12326, rather than a strict pass or fail, quarries producing slates susceptible to air pollutants are forced to produce thicker slates which are then better able to resist the effect of softening. Based on the result of the Sulphur Dioxide Exposure test, one of three grades are applied, and additional action is required by the quarry:

No change

Slates must be at least 8mm in thickness

The Spanish Del Prados are rated S1 for Sulphur Dioxide testing and carry a CE mark.

Summary:

Del Prado Natural Slate fully exceeds both BS EN 12326 and NF 228 standards. In recognition of the high quality of the materials, these slates have been approved for use in National Parks, including Snowdonia, as a suitable alternative to Welsh Slate.

Head Lap

Below are the charts for the recommended head based on both moderate exposure and severe exposure to wind-driven rain. This map can be seen on BS 5534:2014+A2 2018.

United Kingdom

In general, any area that is within 30 miles of a west-facing coastline is considered to be in a severe exposure area.

This being said localised effects on any site must be taken into consideration.

Further reference to BS 8104 is advisable to ascertain localised effects.