75mm Knauf Rocksilk RS80 Building Slab 1.2m x 600mm
FREE delivery over £500 excluding VAT
75mm Knauf Rocksilk RS80 Building Slab 1.2m x 600mm
FREE delivery over £500 excluding VAT
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Product Description
Product Description
Both handover rules held. Here is how RS80 stays clear of RS60, which sits directly beneath it.
RS80's territory is manufacturer-given, not invented. Knauf describes RS60 as designed for multiple thermal, fire protection and acoustic applications. It describes RS80 as designed for multiple applications or for fabrication where mechanical characteristics and thermal performance are key, and labels it high-density against RS60's mid-density. So RS80 leads on mechanical characteristics, fabrication and OEM use throughout. RS60's vocabulary (knitting at joints, friction fit, make-up depth, closing air gaps) is retired for this range and not reused.
One thing you should read before publishing: at 50, 75 and 100mm, RS80 declares exactly the same thermal resistance as RS60. Both are 0.034 W/mK. The pages are written to be straight about that, because pretending otherwise is where these two ranges would start misleading people.
Knauf Rocksilk® RS80 Building Slab
Source: Knauf Insulation Rocksilk® Building Slabs datasheet, October 2025 (KINE4596DAT-V1025), plus Knauf's Rocksilk® RS80 product record. R-values are declared. Datasheet and product record agree on all three SKUs.
50mm Knauf Rocksilk® RS80 Building Slab 1.2m x 600mm
Main Description
50mm Knauf Rocksilk® RS80 Building Slab is a high-density rock mineral wool slab specified where the mechanical characteristics of the insulation matter as much as its thermal figures. Knauf Insulation positions RS80 for multi-application use and for fabrication work, and it is used extensively by OEMs building up thermal, acoustic and fire products where the slab has to hold its form under handling and assembly.
At 50mm the slab declares 1.45 m²K/W of thermal resistance on a conductivity of 0.034 W/mK. On site it goes into internal walls and partitions, light steel frame infill, ground and internal floors, with the density giving a firmer slab to cut, position and retain than lighter grades of the same thickness.
Slabs measure 1200mm x 600mm and are supplied 6 to a pack covering 4.32m², with 16 packs to a pallet for 69.12m² of coverage.
Benefits
- Declared thermal resistance of 1.45 m²K/W at 50mm
- Declared thermal conductivity of 0.034 W/mK
- High-density grade specified where mechanical characteristics and thermal performance are both required
- Euroclass A1 reaction to fire to BS EN 13501-1, the highest classification available
- Used extensively in OEM fabrication of thermal, acoustic and fire products
- Manufactured with ECOSE® Technology, a plant-based binder with no added formaldehyde or phenol
- Firmer to cut and position than lighter grades at the same thickness
- 6 slabs per pack covering 4.32m², 16 packs per pallet giving 69.12m²
Good to know
- Grade is chosen on density, not thermal figures. RS60, RS80, RS100 and RS140 all declare 0.034 W/mK, so at 50mm they all give 1.45 m²K/W. Specify RS80 over a lighter grade for its mechanical characteristics, not for a thermal gain that is not there.
- Fabrication use is a Knauf-stated application. If the slab is being cut, laminated or built into an assembly rather than installed loose, the higher grade is doing real work.
- Reaction to fire is a material classification. A1 describes the slab's own behaviour in fire and does not establish a fire resistance period for the element it goes into.
- Sound absorption happens within the void; the sound reduction figure belongs to the tested partition or floor as a whole.
- Unfaced slab, requiring a lining, board or deck finish. It is not a wearing or decorative surface.
- Store dry and flat, indoors or under cover and off the ground, and keep packs out of prolonged sunlight.
Meta Description (144 characters)
50mm Knauf Rocksilk® RS80 high-density rock mineral wool slab. R 1.45 m²K/W, Euroclass A1, 6 per pack. Competitive pricing and free UK delivery.
75mm Knauf Rocksilk® RS80 Building Slab 1.2m x 600mm
Main Description
At 75mm, Knauf Rocksilk® RS80 Building Slab declares 2.20 m²K/W of thermal resistance and is the thickness Knauf uses as the reference unit for the range's published environmental figures. It suits deeper horizontal zones: intermediate floors, separating floors between dwellings, and pitched roof constructions at rafter level.
Rock mineral wool at this density brings a melting temperature above 1000°C and a stable, self-supporting slab that stays where it was placed across a joist or rafter span. The material is odourless, rot proof and non-hygroscopic, will not sustain vermin, and will not encourage the growth of fungi, mould or bacteria.
The 1200mm x 600mm slab is supplied 4 to a pack covering 2.88m², with 16 packs to a pallet.
Benefits
- Declared thermal resistance of 2.20 m²K/W at 75mm
- Melting temperature above 1000°C
- Non-combustible, achieving Euroclass A1 reaction to fire to BS EN 13501-1
- Absorbs airborne sound within floor, ceiling and partition voids
- Odourless, rot proof and non-hygroscopic, and will not sustain vermin, fungi, mould or bacteria
- Fibres independently certified by EUCEB against Note Q exoneration criteria
- Manufactured under ISO 9001, ISO 14001, ISO 45001 and ISO 50001 management systems
- 4 slabs per pack covering 2.88m², 16 packs per pallet
Good to know
- Separating floors are tested assemblies. Where the floor has to satisfy Approved Document E, build to the tested system specification rather than substituting a grade or thickness on paper.
- Two EPDs exist for RS80. Environmental figures differ between the faced product (S-P-04004, declared at 75mm) and the unfaced product (EPD-IES-0031082). Unfaced slabs are what is supplied here, so quote the unfaced declaration.
- Retain the slab at rafter level. On a pitched roof the slab needs restraint between rafters so it stays in contact with the framing over the life of the roof.
- Trim slabs slightly oversize so they sit tight between joists rather than relying on fixings to hold them.
- U-values for the floor or roof build-up require calculation to BS EN ISO 6946:2017 using BR443:2019 guidance.
- Cover exposed slabs at the end of the working day and in heavy rain. Damaged, wet or contaminated slabs should not be installed.
Technical Datasheets
Technical Datasheets
Customer Information
Customer Information
Free delivery on orders over £500 ex-VAT. All orders below £500 (ex-VAT) are subject to a £50 delivery charge.
Ordering & Delivery
How do I place an order with Insulation UK?
You can place an order for delivery anytime online. If you want to collect from our distribution centre in South Yorkshire then please email us your requirements at sales@insulationuk.co.uk
and we will send a payment link and collection instructions. If you can’t see what you are looking for or need more information, then call our team on 03003 034 578 and we can sort your order from there.
How do I know what’s happening with my order and when I will receive it?
When you have placed your order, you will then receive an email confirmation, giving you an order reference number and asking you to double check everything is correct on your order such as delivery address, quantities etc. If there are any amendments to be made, then please reply to your confirmation email with any details.
Once the team has processed the order you will receive an email with a BY delivery date, this is the latest date you will receive your delivery.
Your final email will be a 24/48hr notification, on the day of the delivery if you need a more accurate ETA then contact the office on 03003 034 578.
Do you offer next-day delivery?
Yes, we do on certain lines, you will see our next day delivery products marked as NEXT DAY. Order before 12pm for next day delivery (charges will apply)
How much does delivery cost and how long will it take?
Standard delivery is £50 + VAT for all orders below £500 excluding VAT, above £500 excluding VAT delivery is free. Bespoke deliveries can be made but will incur charges. Each product page gives you an estimate delivery by date. For more accurate information call the team on 03003 034 578
Can I choose a specific delivery date or time slot?
We will endeavour to try and accommodate a preferred date, if you need a delivery on a certain day, then please call us on 03003 034 578.
Do you deliver nationwide?
We deliver across most of the UK; however, some postcodes are restricted due to their location. Check out our delivery map for more information. If you find that you are in area we don’t deliver to, we have access to a wide range of haulage options, please call the team on 03003 034 578 to discuss your requirements further.
Will the driver help unload the insulation products?
Most of our deliveries are made with vehicles with mechanical off-load (known as a moffett or fork-lift), the driver will leave them in a safe place of your choice. They will help as much as they are allowed but are not insured to bring anything into a property.
What happens if my order arrives damaged or incomplete?
In the unlikely event your order arrives damaged, then please contact within 48 hours at sales@insulationuk.co.uk with any images of the damage and the team will be in touch. If there is anything missing, then notify the team within 48 hours on 03003 034 578
What if my order doesn’t arrive and I have paid for trades to be on site, can I claim anything towards the costs I have incurred?
We advise not to have trades booked in and around the day of your delivery. Things can happen beyond our control, and your delivery may be delayed or abandoned. We cannot be held liable for any consequential loss such as tradesman wages etc.
Product Advice & Support
How do I know which insulation product is right for my project?
With such a variety of insulation products, we fully understand making sure you have the right one can seem daunting. Our team have over 50 years of experience in the construction industry and there isn’t a question they haven’t been asked! Speak to our technical team on 03003 034 578 and they will be happy to offer some help and guidance.
Do you offer technical advice or support before I buy?
Yes we do! Just call 03003 034 578 and ask for our technical team and we will be happy to support you.
Product Information & Suitability
Product descriptions on this website are provided as general guidance only and are not a substitute for the manufacturer’s Technical Data Sheet (TDS), fire classification information, and the project’s design/specification requirements. Suitability depends on the full build-up and intended use (including any requirement for encapsulation, coverings, and compliance with Building Regulations and the project fire strategy).
It is the customer’s responsibility to confirm, before ordering, that the product specification and performance are suitable for the intended application by reviewing the relevant TDS and taking professional advice where required. If you are unsure, contact us before purchase and provide your intended build-up so we can confirm what information we can support.
Nothing in this notice limits or excludes your statutory rights
Can I speak to someone to confirm product specifications?
Of course you can! There is also a range of data sheets and guides available on the product pages under Technical Information.
Are your products suitable for both DIY and trade customers?
Yes, they are. If you are new to DIY projects involving insulation,
then we advise to always do your research. We have a handy guides section which may help.
Do you offer fire-rated or eco-friendly insulation options?
Yes, we do. Fire ratings are indicated in the specification table on the product page, and our sustainable range is continually growing.
Pricing & Payments
Do you offer trade or bulk-buy discounts?
We always aim to offer the best price online; however we do offer project pricing for larger orders, speak to our sales team with your requirements on 03003 034 578.
What payment methods do you accept?
We accept all major cards including American Express, as well as Apple Pay, Google Pay and PayPal
Can I set up a trade account with credit terms?
We do offer trade accounts, however there are certain criteria we ask for, and any credit account application is subject to credit checks. Call the team on 03003 034 578 to discuss any credit applications.
Do your prices include VAT?
The website has a toggle at the top right of the page so the prices can be displayed including and excluding VAT. VAT, where applicable, is charged at checkout.
Returns & Cancellations
Can I return unwanted insulation products?
Contact the team via email sales@insulationuk.co.uk with the items you wish to return and any other information. Please note if we you need us to collect any unwanted items,
a collection fee will apply.
How do I arrange a return or exchange?
Contact the team via email sales@insulationuk.co.uk or check out our refund policy.
Are there any restocking fees?
Restocking charges will apply in certain instances, please contact the team via email at sales@insulationuk.co.uk check out our refund policy.
What if I’ve ordered incorrectly or need to cancel my order?
Contact the team via email as soon as possible. The best way to get in contact is to reply to any of the emails we have sent you, they will come straight through to the team and will have any relevant order information already on there.
Installation & Compliance
Do you offer installation services or just supply materials?
We do not offer any installation services; we are a supplier of insulation and building materials.
Can I get a datasheet or certificate of performance for your products?
Yes, data sheets can be found in the Technical Information drop down on the product page.
How should I store insulation products before installation?
There are a variety of insulation products each with their own storage instructions. Generally, please keep them off the ground, in a dry area, away from the elements.
Sustainability & Quality
Are your insulation products environmentally friendly?
This depends on the individual products, data sheets are available,
and any environmental benefits are noted on the product pages.
Do your products help reduce energy bills?
The correct insulation properly installed can reduce heat loss from a building and therefore help reduce energy costs.
Are your products made in the UK or imported?
With such a wide variety of products some are made in the UK and some are imported.
Customer Service & Support
How can I contact your support team?
By phone on 03003 034 578, email sales@insulationuk.co.uk or via our
webchat online
What are your opening hours?
Monday to Friday 8am to 5pm for sales and technical support, orders can be placed on line 24/7
How quickly can I expect a reply to my enquiry?
We aim to respond to our customers as quickly as possible.
Technical Details
- Brand:
- Knauf
- Material:
- Mineral wool
- Manufacturers Part Number:
- 002411437
- Length:
- 1.2 m
- Width:
- 600 mm
- Thickness:
- 75 mm
- Unit Coverage:
- 2.88 m²
- Qty Per Pack:
- 4 Items
- Applications:
- Walls, Floors, Roof
Thermal performance helps show how effectively the product reduces heat transfer.
Thermal conductivity measures how readily heat passes through the material, so lower figures generally indicate better insulating performance.
R Value shows the material’s thermal resistance at that thickness, so higher figures generally mean stronger insulation performance.
These figures relate to the insulation product itself and should be considered alongside the full wall, roof or floor build-up when checking project requirements.
- Thermal Conductivity:
- 0.034 W/mK
- R Value:
- 2.20 M²K/W
Euroclass reaction to fire is the European EN 13501-1 classification used to show how a construction product behaves when exposed to fire.
The main scale runs from A1 and A2 at the highest end, through B, C, D and E, down to F.
A1 is non-combustible and A2 is limited combustibility, while lower classes indicate a greater contribution to fire.
Euroclass F is the lowest rating on this scale and indicates the weakest reaction-to-fire performance.
This is different from fire resistance, which relates to how long a complete wall, floor or roof build-up can resist fire.
- Reaction to Fire:
- Euroclass A1
