Benuza Blue Heavy Slate: 50cm x 25cm (20" x 10")

Benuza Blue Heavy Slate: 50cm x 25cm (20" 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.
View full product details
In Stock

Starting at £2.03 Inc. VAT


Ring for Availability

Pallet Service

View delivery information
Grouped product items
Product Name Qty
Benuza Blue Heavy Slates: 50 x 25cm (20'' x 10'')
£2.03 Inc. VAT
Benuza Blue Heavy Slates: 50 x 37.5cm (20'' x 15'')
£5.08 Inc. VAT

Need help? Check out our

Buying Guide

Product Details

Benuza Blue Heavy Spanish Slate: 50cm x 25cm (20" x 10")

Benuza Blue Heavy Spanish Slate 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.

All the Benuza Heavy 20 x 10 conform to BS EN 12326, are CE Certified, and are all W1, S1, and T1.

For more information on these standards and other information on Slates 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 have strong vertical grain whilst having similar colour and characteristics to a traditional Welsh Blue slate, making them appropriate for use in National Parks and Conservation areas.

The Benuza Blue slates are virtually inclusion-free and come with a 30-year quarry-back guarantee.

These slates can go down to 25° with the appropriate head lap is in place and there are 19.6 slates per m². Each slate weighs approx. 2.1Kg each.

Head Lap

Below 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 mentioned, 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 in a 16 x 10 as a Well-Graded 1st mix or as a 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.

Read More

Copyright 2021 Ashbrook Roofing and Supplies Ltd. (Harrison Way, Matlock, Derbyshire, DE4 2LF) Company Registration Number: 4549398 | VAT Number: 419721937 | Telephone: 01629 828 500 | Email: