Insulation for a better tomorrow
Rainscreen Cladding

Rainscreen Cladding

External walls

URSA Walltec 32B and URSA Façade N35 slabs are for use behind rain screen cladding systems, both new build and refurbishment. The slabs have a black glass fleece facing so they can be used in open joint cladding systems without being seen.

URSA Walltec 32B - thermal conductivity 0.032 W/mK.

URSA Façade N35 - thermal conductivity 0.035 W/mK.

Design

Rainscreen cladding is a lightweight, non-load bearing system attached to the outside of a building using a bracket and rail system. The cladding system provides protection from wind and rain, improves the thermal performance and limits solar gains. A ventilated void, typically 50mm, behind the cladding keeping the system dry.

Rainscreen systems are also available that use a traditional brick (or block) external leaf and nominal 50mm clear cavity.

The class leading performance URSA Walltec 32B, thermal conductivity 0.032 W/mK, provides a continuous envelope of insulation around the building. Alternatively URSA Façade N35, thermal conductivity 0.035 W/mK, may be used. The ventilated cavity and external insulation protect the building from summer overheating whilst during the heating season advantage can be taken of the high thermal mass of concrete framed buildings.

URSA Walltec 32B and URSA Façade N35 are totally non-combustible, Euroclass A1, so do not add any fire load to the building or prejudice the overall fire performance of the wall. The presence of the ventilated cavity behind the cladding system means that cavity barriers as required to prevent the spread of fire and/or smoke. It is recommended that horizontal cavity barriers are installed at every compartment floor level, at roof level and if required vertical barrier to further sub-divide the cavity at compartment walls. See Approved Document B (England & Wales) and the Fire Section of the Technical Handbooks (Scotland). Similarly all openings should be correctly fire stopped to prevent a fire from inside the building being able to break into the cavity.

These design recommendations show compliance with all relevant sections of the Building Regulations and NHBC Standards.

It should be noted that the Approved Document B for England & Wales requires insulation products in high rise (18m or more) cladding systems be of ‘limited combustibility’ or better. In Scotland the insulation should be totally ‘non-combustible’

Installation

Rainscreen Cladding

URSA Façade/URSA Walltec is mechanically fixed to the wall structure between the brackets used to support the cladding system. The usual procedure for construction is;

  1. Timber and metal stud framed walls should include a suitable air and vapour control layer on the inner surface behind the plasterboard. Timber frame walls should also include a breather membrane external to the sheathing.
  2. The cladding system brackets are fixed to the main structural wall in accordance with the manufacturer’s instructions.
  3. Fix the URSA Facade/URSA Walltec slabs to the wall in a staggered pattern, black face outermost. The slabs may be fitted in either landscape or portrait format. Ensure all joints are tightly butted together and that the slabs are cut accurately and tightly around the brackets ensuring that there are no gaps. Leaving the slabs cut slightly oversize ensures that the fibres will ‘knit’ together. The slabs cut easily with the use of a sharp knife.
  4. The URSA Façade/URSA Walltec slabs are mechanically fixed to the wall using suitable insulation retaining fixings (with a minimum head diameter of 70mm) depending upon the substrate. A typical fixing pattern is three fixings along the centre line of the slab – the central fixing in each slab must be metal rather than plastic. Alternatively use a plastic fixing at the corner of each slab with a with a metal fixing at the centre. Do not overdrive the fixings.
  5. Ensure that cavity barriers are installed in accordance with the Building Regulations. In high rise this would include at every compartment floor level and at the top of the cavity. Ensure external openings are correctly sealed also.
  6. URSA Façade/URSA Walltec is robust enough to be left exposed and will withstand short term, intermittent wetting. If prolonged bad weather (rain, snow, high wind, freezing conditions) is predicted fit only sufficient slabs that can be covered and protected by the cladding on the same day; otherwise provide temprary weather protection.
  7. Once the insulation is fitted the external cladding work may proceed in accordance with the manufacturer’s instructions.

URSA Walltec 32B U-values

Rainscreen Cladding

URSA Walltec 32B (mm)

U-Value (W/m²K)

150mm light steel stud

U-Value (W/m²K)

150mm dense masonry

100 0.20 0.36
120 0.19 0.32
140 0.17 0.29
160 0.16 0.27
180 0.15 0.25
200 0.15 0.24

Brick Outer Leaf Cladding

URSA Façade/URSA Walltec is mechanically fixed to the wall structure behind the restraint channel used to tie the brick or block outer leaf to the structure. The usual procedure for construction is;

  1. Timber and metal stud framed walls should include a suitable air and vapour control layer on the inner surface behind the plasterboard. Timber frame walls should also include a breather membrane external to the sheathing.
  2. Fix the URSA Facade/URSA Walltec slabs horizontally in a staggered, brick bond, pattern with the black face outermost.. Ensure all joints are tightly butted together and that the slabs are cut accurately around openings and penetrations. The slabs cut easily with the use of a sharp knife.
  3. To assist in their installation the URSA Façade/URSA Walltec slabs may be initially fixed to the wall using suitable insulation retaining fixings (with a minimum head diameter of 70mm). One fixing per slab (or part slab) is normally sufficient.
  4. Ensure that cavity barriers are installed in accordance with the Building Regulations. In high rise this would include at every compartment floor level and at the top of the cavity. Ensure external openings are correctly sealed also.
  5. Once the insulation is fitted install the channel restraint system, normally at 600mm horizontal centres, using suitable bolts or screws (depending upon substrate) with compression sleeeves. Follow the manufacturer's instructions.
  6. The brick or black outer leaf is built in accordance with good practice using ties slotted into the restraint channel.
  7. URSA Façade/URSA Walltec is robust enough to be left exposed and will withstand short term, intermittent wetting. If prolonged bad weather (rain, snow, high wind, freezing conditions) is predicted fit only sufficient slabs that can be covered and protected by the cladding on the same day; otherwise provide temprary weather protection.

URSA Walltec 32B U-values

Brick Outer Leaf

URSA Walltec 32B (mm)

U-Value (W/m²K)

150mm light steel stud

U-Value (W/m²K)

150mm dense masonry

100 0.16 0.27
120 0.15 0.23
140 0.13 0.20
160 0.12 0.18
180 0.11 0.16
200 0.11 0.15

For further information and more U-values see our technical brochure in the Documents section. Alternatively please contact URSA Technical Department.

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