CAVITY
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CAVITY Insulation for masonry cavity walls

CAVITY ROCKWOOL® Cavity insulation is a semi-rigid, full-fill insulation solution for masonry cavity wall construction, suitable for use in new builds or extensions. Lightweight and easy to handle, the batts are simple to install and provide a close fit against brick and blockwork. ROCKWOOL Cavity full fill insulation batts are non-combustible and contain water repellent additives which prevent moisture transmission between the outer and inner leaf.

Outstanding thermal, fire and acoustic insulation Acts as a cavity barrier Water repellent - prevents water transmission from outer to inner leaf Superior fit against blockwork Dimensional stability - no sagging or slumping ROCKWOOL Cavity Batts provide thermal protection for external masonry walls, and thermal and sound protection within masonry party walls, between dwellings. The batts are quick and easy to accurately cut, and provide a great fit; reducing installation time, avoiding gaps and cold spots, and maximising long term performance. ROCKWOOL Cavity Batts are also used in masonry...

Performance Thermal ROCKWOOL Cavity Batt has a thermal conductivity of 0.037 W/mK. Fire classification Achieves a reaction to fire classification of A1, as defined in EN13501-1. Resistance to fire spread between and within cavities. ROCKWOOL Cavity is non-combustible and therefore suitable for use in buildings of every purpose group. It also acts as an effective cavity barrier when tightly fitted between masonry leaves where an insulated wall connects with an uninsulated wall cavity. Water resistance and moisture The product will resist the transfer of water across the cavity. The...

Table 1 - Construction 1: 102mm Facing brick outer skin, ROCKWOOL Cavity full fill, 100mm internal concrete block (various densities) Internal finishes: light plaster or plasterboard on dab. Inner block Internal finish Light plaster Light plaster Light plaster Light plaster Plasterboard on dabs OR light plaster Concrete block inner leaf Cavity Batt Cavity wall tie Facing brick outer skin Table 2 - Construction 2: Render on 100mm medium dense block outer, ROCKWOOL Cavity full fill, 100mm internal concrete block (medium dense or Standard Aircrete) Internal finishes: light plaster or...

Party wall “thermal bypass effect” - achieving a zero heat loss Approved Documents L1A & L2A of England and Wales and Section 6 of Scotland’s Building standards have recognised that where party cavity-walls between connected buildings are untreated, considerable heat can escape through them. A key feature of the SAP calculation is that party wall cavities should have a zero heat loss (U-value 0.0W/m2K). If these cavities are left unfilled and unsealed, a U-value of 0.5W/m2K will automatically be applied, making it extremely difficult to meet the TER compliance. In calculating the DER for a...

Installation Designing the cavity wall The use of ROCKWOOL Cavity does not affect the choice of wall ties to BS EN 845-1 or DD140. Ties should be selected according to structural requirements, cavity size, building height and location. The outer leaf is the first line of defence against rain and the following will help to improve its effectiveness: 1. Consider the dimensional tolerances of the wall before designing the width of the cavity. An extra 5mm above the nominal batt thickness will normally be sufficient. 2. Select bricks conforming to EN771-1 that are appropriate to the exposure...

Installing ROCKWOOL Cavity 1. The installation of the batts should commence below the damp proof course (preferably by at least 150mm) with no risk of capillary action to minimise cold bridging. The bottom row of ties should be at 450mm centres horizontally. If necessary, the width of the first course of batts can be cut to suit the height of the next row of wall ties. The width of cut batts should always be 5mm greater than the width to be insulated, e.g. wall tie centres. 2. It is recommended that the external leaf be constructed ahead of the internal one so that any mortar protruding...

6. Raise the second leaf to the same level as the batts. 7. The as-built cavity width must not exceed the following dimensions: Nominal Batt thickness (mm) Permitted deviation maximum as built cavity widths (mm) Please note: Where two layers of ROCKWOOL Cavity batts are used, ensure that the vertical joints between the outer batts are staggered to those of the inner batts. 8. Repeat this sequence to the top of the wall (see Figure 5). Alternatively, the top of the batts can be protected by using a cavity tray. 9. To minimise water penetration to the inner leaf during driving rain, it is...

As an environmentally conscious company, ROCKWOOL promotes the sustainable production and use of insulation and is committed to a continuous process of environmental improvement. Made from a renewable and plentiful naturally occurring resource, ROCKWOOL insulation saves fuel costs and energy in use and relies on trapped air for its thermal properties. All ROCKWOOL products provide outstanding thermal protection as well as four added benefits: Fire resistance Acoustic comfort Sustainable materials Durability ROCKWOOL insulation does not contain (and has never contained) gases that have ozone...

ROCKWOOL Limited reserves the right to alter or amend the specification of products without notice as our policy is one of constant improvement. The information contained in this brochure is believed to be correct at the date of publication. Whilst ROCKWOOL will endeavour to keep its publications up to date, readers will appreciate that between publications there may be pertinent changes in the law, or other developments affecting the accuracy of the information contained in this brochure. The applications referred to within the brochure do not necessarily represent an exhaustive list of...

April 2020 ROCKWOOL Limited Pencoed Bridgend CF35 6NY Tel: 01656 862 621 info@rockwool.co.uk rockwool.co.uk