Benuza Blue Heavy Slate: 40cm x 25cm (16" x 10")

Benuza Blue Heavy Slate: 40cm x 25cm (16" x 10") grouped
  • Heavy grade quality blue-grey roofing slate.
  • Transforms into a beautiful slate roof with a strong depth of character and shadow line.
  • Strong vertical grain produces a naturally stronger slate.
  • Consistent, well-graded and easy to work slate.
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Grouped product items
Product Name Qty
Benuza Blue Heavy Slates: 40 x 25cm (16'' x 10'')
£1.51 Inc. VAT
Benuza Blue Heavy Slates: 40 x 37.5cm (16'' x 15'')
£3.76 Inc. VAT

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Product Details

Benuza Blue Heavy Slate: 40cm x 25cm (16" x 10")

Benuza Blue Heavy Slates is a rugged version of the Benuza Blue 1st grade roofing slate. Quarried from the same mountains in La Bana, Benuza Blue Heavies offer you a stronger slate, more characterful shadow-line, and deeper depth and contrast than a standard or first-grade slate.

Heavy slates are traditionally used in areas of high wind or heavy snowfall.

As such they are a slate ideally suited for a cottage, or older buildings where the character is key. Additionally, the Benuza Blue Heavy looks fantastic on barn conversions, where a thinner, cleaner slate would look out of place.

The Benuza Blue lies extremely well for a heavy slate - a testament to the high-quality control at the quarry.

This slate meets all the British standards needed for roofing in the UK, is CE Certified, and meets all the requirements for W1, S1, T1. For more information on slating standards visit our resource centre.

Slate Specification:

Specification Value
Nominal Thickness 7-9mm 
Deviation of Length, Width, Edge Straightness & Rectangularity Complies
Mechanical Resistance 

Transversal: 52.9 N/mm²

Longitudinal: 57.7 N/mm²

Water Absorption W1 (≤0.6%)
Apparent Calcium Carbonate <5%
Thermal Cycling T1
Exposure S1
Non-Carbonate Carbon Content Complies (≤2%)
External Fire Performance Deemed to Satisfy
Reaction to Fire Deemed to satisfy class A1
Release of Dangerous Substances None in specified conditions of use

These slates can be fitted down to a 30° pitch with a coverage of 26.1 slates per m², and are virtually inclusion-free (pyrite), leaving no unsightly rust marks or steaks in the future of your roof. These slates have a life expectancy of 100 years with a 30-year quarry-backed guarantee.

Head Lap

Exposure MapBelow are the charts for the recommended headlap and rafter pitch based on a sheltered to moderate area 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.

*Image used in accordance to the Open Government License V3 -

Slate Size 25° 30° 35°
500 x 250 95mm 80mm 70mm
500 x 250H 95mm 80mm 70mm
400 x 250 - 80mm 70mm
400 x 250H - 80mm 70mm

If you know the quantities required, then you are welcome to order online. If you would like us to provide a free estimate from your plans, require a sample or two, or would like to have a general chat about all things roofing, then please give us a call on 01629 732988.

Benuza Blue Slates are also available as a Well-Graded 1st mix or as a larger 20 x 10 Heavy.

We also have a slate presentation put together by our slate specialist.

This is worth looking at to widen your knowledge, help you to make the important decision and to know what factors to consider when buying slate.

Please select here to view.

Product Delivery

Ashbrook Roofing offers Pallet Deliveries across the United Kingdom. (excluding the Highlands, Islands and Ireland)

Delivery expectation for orders placed before 14.00hrs (Mon - Fri) are:

  • Pallet Service - 2-3 Working Days


Pallet Service orders will be arranged beforehand with the customer as someone will need to be on site to accept the goods.


There is an additional delivery charge based on the weight of the goods. (£60 base charge for items under 750Kgs) 

And remember, if you need help, have any concerns or if you need a delivery extra quickly, simply give our customer service team a call on 01629 828500, or email us and we'll do our very best to help.

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