Q1. Brief description of what stone wool is:
A1. Rockwool stone wool insulation is manufactured from naturally occurring, sustainable igneous volcanic rock. It is extremely thermally efficient, has a low embodied energy of 16.8MJ/Kg and is rated as having zero Ozone Depleting Potential (ODP) and zero Global Warming Potential (GWP).
Q2. What is Hardrock, why it’s used and where?
A2.Rockwool’s Hardrock dual density roofing boards avoid the need for a fire-resistant ceiling to stop fire spreading over a compartment wall, providing significant cost savings. Where a ceiling is required - in schools, hospitals or commercial property for example - they enable the installation of non fire-resistant ceilings (i.e. suspended ceiling tiles in a grid) directly below the roof structure.
Q3. What are the product benefits e.g. fire, sustainable, thermal performance, etc?
A3. Rockwool’s Hardrock flat roofing insulation offers superior thermal, fire, acoustic and sustainable performance and meets legislative directives for building performance and the use of sustainable materials. It is made primarily from volcanic rock and offers a combination of properties that no other insulation material can match. It can withstand temperatures of more than 1,000oC and has the highest CEN Fire Certification A1 rating, which means that it is classed as non-combustible.
Q4. What is its thickness?
A4.There are minimum thermal requirements for building elements under Part L. In the case of flat roofs the minimum requirement is a U-value of 0.25W/m2K, which equates to 150mm Hardrock; however, the thicknesses may vary considerably due to design requirements. If the insulation is required to achieve a fall on the roof for the purposes of drainage, then this could affect the thickness; equally the requirement to achieve an improved U-value as determined by the ‘whole building’ calculation (e.g. SBEM or SAP) often increases the thickness. The thicknesses of the Hardrock flat roofing insulation range from 145mm to 280mm to achieve the full range of U-values (0.25W/m2K to 0.16W/m2K).
Q5. Distribution - where is it purchased?
A5. Rockwool products are normally sold via builders’ merchants and insulation distributor networks that specialise in stocking and distributing insulation and ancillary products.
Q6. How is it specified?
A6. The product is specified typically by the architect who may have received advice from another party, e.g. an acoustics engineer or a Rockwool technical consultant. The product would be specified on drawings or specification pages in the form of an NBS clause.
Q7. Does it have any guarantees?
A7.All Rockwool products are covered by Product indemnity.
Q8. Price per square metre?
A8. Prices vary according to factors such as thickness, delivery method, quantity, or, for example, if a tapered scheme is required, etc. However, Rockwool’s prices are competitive.
Q9. Rockwool website and contact details
A9.There are two websites available where information relating to the product can be found:
The main Rockwool website: www.rockwool.co.uk
The micro website: www.rockwoolfireproof.co.uk (predominantly promoting the fire characteristics and legislation relating to flat Roofs. However, all general product information, e.g. literature, is also available)
