Frequently asked questions

Frequently asked questions

FAQS

You can find the most frequently asked questions about our products and applications below. If you can not find the answer to your question please contact our team who will be happy to assist.

General questions

What is the difference between stone wool and other types of insulation?

ROCKWOOL stone wool is made from volcanic rock and achieves an European Reaction to Fire Classification of A1 - non combustible. Stone wool is also a durable choice; its properties and benefits don’t reduce or change over time and the product will effectively perform for the lifetime of the building.

How long will a ROCKWOOL product last before I need to replace it?

ROCKWOOL stone wool is made from volcanic rock and achieves an European Reaction to Fire Classification of A1 - non combustible. Stone wool is also a durable choice; its properties and benefits don’t reduce or change over time and the product will effectively perform for the lifetime of the building.

What acoustic qualities does ROCKWOOL insulation have?

ROCKWOOL is used by specialists in many demanding acoustic applications. ROCKWOOL stone wool works in two distinct ways to reduce noise, either by impeding the transmission of sound through an element of the structure or by absorption of sound at the surface.

What environmental impacts/benefits are there from using ROCKWOOL products?

The natural basic rock material for making ROCKWOOL products is an abundant resource. Great care is taken during both the manufacturing process and distribution of finished insulation products to minimise any environmental impact. ROCKWOOL operation team monitors the production processes carefully to ensure any emissions are within specified limits. It is ROCKWOOL Group policy to adhere to environmental standards better than national or local requirements. Please visit the Sustainabilty section of the website or the Sustainabilty brochure for more in-depth information.

If ROCKWOOL is made of stone, will it be heavier than other types of insulation

Although ROCKWOOL stone wool is made of rock, the natural material has been converted to a fibrous wool substance which is not difficult to handle. You might need someone to help manoeuvre the packaged product up into the loft space but one person can easily handle our roll and loose lay products alone.

What dB rating can I achieve with ROCKWOOL insulation?

The dB rating (acoustic performance) of any ROCKWOOL product is determined by the total construction. The acoustic performance of a construction will be dependent upon the sound path, the mass and absorbative qualities of the products used within the construction. ROCKWOOL products have been tested in a number of standard constructions, details of which are contained within the Soundpro brochure.

How do I reduce noise from next door?

We have a range of tested solutions for walls, floors and flanking sound transmission to meet or exceed the current acoustic requirements for Approved Document Part E. 

How do I cut ROCKWOOL to fit?

ROCKWOOL insulation can easily be cut with a long bladed knife or insulation saw available from DIY outlets. Please ensure all safety gear is worn during the use of insulation.

What density is ROCKWOOL?

There is no single answer to this. ROCKWOOL products are destined for a wide variety of applications needing different densities, each of which is designed into the product at the manufacturing stage.

The most familiar ROCKWOOL product will be ROCKWOOL Roll , a light density 22 kilogram per cubic metre (kg/m³)material used typically for loft insulation. At the other end of the density range is a system for cladding buildings using a high density panel - ROCKPANEL - of compressed ROCKWOOL at over 1000 kg/m3.

The versatile range of ROCKWOOL products includes rolls, slabs, boards, dual density systems, mats, pipes, fabricated and loose wools, all of which are provided in a range of densities and thicknesses suitable for their best application.

What environmental impacts/benefits are there from using ROCKWOOL?

The natural basic rock material for making ROCKWOOL is an abundant resource. Great care is taken during both the manufacturing process and distribution of finished insulation products to minimise any environmental impact. ROCKWOOL's operation team monitors the production processes carefully to ensure any emissions are within specified limits. It is ROCKWOOL Group policy to adhere to environmental standards better than national or local requirements. Please visit the Sustainabilty section of the website or the Sustainabilty brochure for more in-depth information.

Will ROCKWOOL insulation attract rodents or mould?

ROCKWOOL insulation is a naturally inert, rot proof material that does not encourage or support the growth of funghi, moulds or bacteria. ROCKWOOL insulation does not offer sustenance to insects or vermin.

Walls

Which ROCKWOOL external wall systems can be used to insulate facades, and improve older housing?

We have a number of options:- REDArt® is an external wall insulation system which offers the complete thermal and aesthetic renovation of facades. It is used in refurbishment and new build projects to provide an enhanced exterior appearance for tower blocks, shops, schools, public buildings and housing. With a range of colours and finish options, vibrant new schemes can be created. The system is installed by Approved ROCKWOOL Installers using ROCKWOOL insulation slabs mechanically fixed and/or bonded to the old wall substrate, onto which a series of REDArt® renders or finishes is applied. RAINSCREEN DUO SLAB® is a specially designed dual density insulation product for direct fixing to facades where a rainscreen cladding system has been selected. The outer higher density surface is robust and designed to allow for exposure to weather conditions while cladding systems are erected. Meanwhile, the inner surface makes consistent close contact with the old exterior of the building, providing a significant improvement in thermal performance. Cladding options available can be found on the ROCKPANEL website.

How do I reduce noise from next door?

We have a number of options:- REDArt® is an external wall insulation system which offers the complete thermal and aesthetic renovation of facades. It is used in refurbishment and new build projects to provide an enhanced exterior appearance for tower blocks, shops, schools, public buildings and housing. With a range of colours and finish options, vibrant new schemes can be created. The system is installed by Approved ROCKWOOL Installers using ROCKWOOL insulation slabs mechanically fixed and/or bonded to the old wall substrate, onto which a series of REDArt® renders or finishes is applied. RAINSCREEN DUO SLAB® is a specially designed dual density insulation product for direct fixing to facades where a rainscreen cladding system has been selected. The outer higher density surface is robust and designed to allow for exposure to weather conditions while cladding systems are erected. Meanwhile, the inner surface makes consistent close contact with the old exterior of the building, providing a significant improvement in thermal performance. Cladding options available can be found on the ROCKPANEL website.

I have a masonry cavity wall, will blowing insulation within the cavity reduce the noise from next door?

Using ROCKWOOL Cavity or ROCKWOOL Energysaver to fully fill a separating blockwork cavity wall can help to reduce flanking sound within the cavity space. This is an effective treatment for addressing speech, television and general living noise, and will typically boost performance by around 3 - 8 dB.

Which type of cavity wall insulation is best?

There are basically three choices. If you are building new property, ROCKWOOL Cavity Wall Batts will provide maximum energy savings. These fully fill the cavity, yet their special water repellency prevents water transmission across the cavity. If 'low energy' design is involved, wide cavity structures can use double thicknesses of ROCKWOOL Cavity Wall Batts to create improved U- values. The second choice is ROCKWOOL High Performance Partial Fill Cavity Slab. This is a system which allows a cavity to be maintained by clip fixing the special dual-density slabs against the inner leaf. This specially engineered product offers enhanced performance due to the consistent close fit achieved against the uneven surface of the inner leaf masonry. The third alternative is for both new-build and existing property (subject to survey). ROCKWOOL ENERGYSAVER® Cavity Wall Insulation is a blown wool system operated by Approved ROCKWOOL Installers subject to BBA inspection. Holes are drilled at pattern intervals in the outer (or inner) leaf of the cavity wall and granulated ROCKWOOL is blown into the cavity space to fill to a pre-determined density. The holes are then made good with matching mortar. This system achieves effective improvement of U-values especially for existing poorly insulated houses. Domestic installation carries a 25 year CIGA guarantee. 

I am insulating a music room. What products do you recommend?

We would suggest lining the walls with a tissue faced slab such as ProRoxSL 930 (RW3) or ProRoxSL 950 (RW4). The insulation product would then need to be protected from damage. Typically, this would be achieved by installing a perforated sheet. 

Is my house suitable for cavity wall insulation?

Approved CIGA installers will carry out an inspection to assess the suitability of the property to have blown insulation installed. Further information regarding approved installers and what to expect can be found on the CIGA website.

Floors & Ceilings

How do I reduce noise from adjoining floors?

Acoustic improvement can be complicated, but there are several ROCKWOOL products and systems which can help reduce interference sounds though structures. Impact, reflective and penetrating sounds transmit in different ways and behave differently in varying frequency ranges. The principle on which ROCKWOOL acts successfully as an acoustic insulant is by diffusing and absorbing the sound waves. For floors, the ROCKWOOL Acoustic Floor system can be built up to combat the level of noise transmission. Slimfloor is a composite product of ROCKWOOL and chipboard dedicated to sound protection for concrete floors. ROCKFLOOR® is an insulation board for both thermal and acoustic performance in a variety of buildings. See SOUNDPRO® Brochure for further details. 

Do you have a 1 hour fire rated timber floor construction?

Yes - ROCKWOOL Flexi 100mm has been tested to provide the 1 hour fire resistance to timber joisted floor constructions. Chicken wire galvanised steel mesh, nominal 25mm mesh size x 0.7mm thick, is fitted over the joists so that it is in contact with the top and sides of each joist and in contact with the upper face of the ceiling. ROCKWOOL Flexi, 100mm thick, is fitted between the joists so that it is in contact with the mesh trays and therefore nominally flush with the bottom of the joists.  

Can ROCKWOOL be installed underneath site concrete or screed?

Yes, ROCKFLOOR® is the ideal product for this. The desired thickness of ROCKFLOOR® can be laid on a dry, firm surface, and flooring applied immediately over it to create a warm free-floating floor, which has thermal, acoustic, and fire protective properties. ROCKFLOOR® will accommodate all traditional flooring coverings. ROCKFLOOR® can also be laid on a ground floor over a dpc membrane with a concrete screed poured directly over it, providing an insulated platform. The thickness of the screed will vary depending on the intended load.

Does ROCKWOOL have 1 hour fire rated timber floor construction?

Yes - ROCKWOOL Flexi 100mm has been tested to provide the 1 hour fire resistance to timber joisted floor constructions. Chicken wire galvanised steel mesh, nominal 25mm mesh size x 0.7mm thick, is fitted over the joists so that it is in contact with the top and sides of each joist and in contact with the upper face of the ceiling. ROCKWOOL Flexi, 100mm thick, is fitted between the joists so that it is in contact with the mesh trays and therefore nominally flush with the bottom of the joists.

How do I reduce noise from downstairs?

Acoustic improvement can be complicated, but there are several ROCKWOOL products and systems which can help reduce interference sounds though structures. Impact, reflective and penetrating sounds transmit in different ways and behave differently in varying frequency ranges. The principle on which ROCKWOOL acts successfully as an acoustic insulant is by diffusing and absorbing the sound waves. For floors, the ROCKWOOL Acoustic Floor system can be built up to combat the level of noise transmission. Slimfloor is a composite product of ROCKWOOL and chipboard dedicated to sound protection for concrete floors. ROCKFLOOR® is an insulation board for both thermal and acoustic performance in a variety of buildings. See SOUNDPRO® Brochure for further details.

Roofs

Should loft insulation be fitted between the joists or be placed over the joists?

The most effective way to insulate your loft is to have a layer of insulation that sits snugly in the spaces between the joists (either a roll product or loose lay) followed by a top layer crossways across the joists. The total depth of the insulation should be at least 270 – 300 mm for the best results and to meet current building regulations.

Can ROCKWOOL products be used for the pitched rafters of a roof?

Yes - ROCKWOOL FLEXI® can be used between the rafters. The flexible edge of the product allows for a tight fit between rafters therefore minimising cold bridges. Alternatively, a warm pitched roof system is available which utilises ROCKWOOL FLEXI® between the rafters and a overlay board of Hardrock over the top of the rafters. Solutions can be found in the ROCKWOOL Part L brochure.

I want to top up my loft insulation but what is already there isn’t stone wool. Do I need to remove this or can I just lay a ROCKWOOL product on the top?

You can simply top up any existing insulation with ROCKWOOL. Our loose lay product means you can fill any gaps around the edges easily before laying a roll of insulation over the top.

Do I need to maintain the ventilation at the eaves of the roof or can I fit the roll insulation into this void?

With better insulation, the loft will be colder and therefore more prone to condensation if not adequately ventilated. It is therefore important to maintain the air flow through the loft space normally via the eaves. This air flow can be maintained by installing eaves ventilators.

When installing recessed lighting within a ceiling are there any precautions required if there is already insulation between the joists?

It is recommended that when installing down lighters within a ceiling you should install acoustic/fire covers to maintain an air void/flow around them. This prevents the light from over-heating which could cause the light's to fail more frequently. These are available from DIY merchants.

HVAC

Can ROCKWOOL products help reduce noise transmitted through pipes and air conditioning systems, or from plant and machinery?

Yes, there are several products which can help. Our product's proven combination of high acoustic porosity, acoustic frictional resistance and light weight makes it ideal for use in a wide range of demanding situations. Products to look for include ProRox range of slabs, Techwrap and Techtube, Ductwrap and ductslab and pre-formed pipe sections such as H&V sections.  

Can ROCKWOOL help reduce noise transmitted through pipes and air conditioning systems, or from plant and machinery?

Yes, there are several products which can help. ROCKWOOL's proven combination of high acoustic porosity, acoustic frictional resistance and light weight makes it ideal for use in a wide range of demanding situations. Products to look for include ProRox range of slabs, Techwrap and Techtube, Ductwrap and ductslab and pre-formed pipe sections such as H&V sections.

Contact us

If you have not been able to find the answer to your question please contact us and a ROCKWOOL representative will be happy to help.
If you have not been able to find the answer to your question please contact us and a ROCKWOOL representative will be happy to help.
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