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Celotex CW4000 Cavity Wall Boards

Celotex CW4000 Cavity Wall Boards

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A partial fill insulation solution for masonry cavity walls, Celotex CW4000 is a high performance, rigid polyisocyanurate (PIR) insulation board suitable for use in new buildings and extensions. Sized to fit between cavity wall ties, it is easy to handle and install.

Celotex CG4000 is a high performance PIR solution specifically designed for use within partial fill cavity wall applications.

  • Is easy to fit between wall ties using cavity tie clips for retention
  • Comes in thicknesses ranging from 25mm-100mm
  • Features a good reaction to fire performance when measured in accordance with new European standards
  • Comes in conveniently sized boards for installation between cavity wall ties
  • Includes low emissivity foil facings
  •  giving improved thermal insulation with cavity air spaces
  • Has excellent dimensional stability
  • Provides reliable long term energy savings for buildings
Other Features
  • Has a lower thermal conductivity value (0.022w/mK) compared with other typical pir insulation boards providing enhanced thermal performance
  • is low Gwp and zero odp rated
  • Has the best fire performance of any pir insulation board. CG4000 is Class o rated throughout the entire product in accordance with BS 476
  • is available in a range of thicknesses from 40mm-100mm and in a board size of 1200mm x 450mm
  • includes low emissivity textured aluminium foil facings giving improved thermal performance within cavity air-spaces
  • is specifically targeted at partial-fill cavity wall applications

Product Application

Technical Spec


Celotex CW4000 Cavity Wall Technical Data

Product Code

Board dimensions (width) x (length) = (m²)

Thickness (mm)

R-value (m2K/W)

U-value (W/m²K)

Weight (kg/m2)

Pack weight (kg)

Celotex CW4025

20x0.45x1.2 = 10.8m²

25

1.10

0.91

0.85

9.18

Celotex CW4040

12x0.45x1.2 = 6.48m²

40

1.80

0.56

1.26

8.16

Celotex CW4045

11x0.45x1.2 = 5.94m²

45

2.00

0.50

1.40

8.32

Celotex CW4050

10x0.45x1.2 = 5.4m²

50

2.25

0.44

1.55

8.37

Celotex CW4060

8x0.45x1.2 = 4.32m²

60

2.70

0.37

1.88

8.12

Celotex CW4065

7x0.45x1.2 = 3.78m²

65

2.95

0.34

2.03

7.67

Celotex CW4070

7x0.45x1.2 = 3.78m²

70

3.15

0.32

2.17

8.20

Celotex CW4075

6x0.45x1.2 = 3.24m²

75

3.40

0.29

2.32

7.52

Celotex CW4080

6x0.45x1.2 = 3.24m²

80

3.60

0.28

2.46

7.97

Celotex CW4090

5x0.45x1.2 = 2.7m²

90

4.05

0.25

2.74

7.40

Celotex CW4100

5x0.45x1.2 = 2.7m²

100

4.50

0.22

3.28

8.86

Thermal conductivity / Lambda value (W/mK) = 0.022: R-value = Thermal Resistance; U-value = Thermal Transmittance Coefficient; Compressive strength (kPa) = ≥ 120: Dimensional stability = DS(TH)8; Water vapour resistance (MNs/g) = > 150: Surface spread of flame = Class 1 (25mm - 90mm only)



Installation Instructions

Celotex Cavity Wall CW4000 Installation

General
  • Celotex insulation boards should not be installed when the temperature is at or below 4°C and falling.
  • The wall ties used must be suitable for the structural requirements and incorporate a retaining clip to ensure that the insulation is held permanently in place. Normally the insulation is fitted against the inner leaf of the wall.
  • BBA-approved wall ties and clips should be used wherever possible. The advice of the wall tie manufacturers should be followed, but Celotex does not consider butterfly ties to be suitable for use with partial-fill cavity insulation.
  • The first row of board-retaining wall ties should be installed at least one course below the damp proof course (DPC) and positioned at maximum 600mm centres horizontally, to provide a minimum support of two ties per 1200mm board.
  • The second and subsequent rows of ties should be installed at 450mm centres vertically and maximum 900mm centres horizontally. Where required for structural purposes, it may be necessary to install ties at closer centres.
  • Always ensure that each full or cut board is retained by no fewer than three ties around its perimeter.
  • Fit the boards between the wall ties, and secure in place with a retaining clip on each tie. Ensure that horizontal and vertical joints are tightly butted to minimise heat loss.
  • At openings such as doors and windows, use a proprietary insulated cavity closer.
  • Where necessary, cut the boards to size using the Celotex Insulation Saw and straight edge.
  • Where the cavity is closed at or below DPC level by a methane barrier membrane, use mechanical fixings to secure the board to the brickwork above the DPC. Avoid puncturing the gas barrier membrane.
  • At internal (see Fig.1) and external (see Fig.2) angles, ensure that the thickness of the board continues around the angle and that sufficient wall ties are used. Gable walls At gable walls (see Fig.3) it is recommended that Celotex CW4000 is taken up to the underside of the roof verges. In cold roof constructions, the product should extend at least 250mm above the ceiling insulation. The top edge of the insulation should be protected with a cavity tray.
Cavity fire barriers
Cavity barriers are not required in any walls that comply with Approved Document B3 diagram 32, but the cavity must be closed at the top and around any openings. Celotex CW4000, being a non-melting thermoset material, may pass through cavity barriers so that a thermal bridge is avoided.

Cavity obstructions
Unavoidable projections into the cavity, such as floor edge beams and steel columns, need careful detailing and may require a horizontal cavity tray.
To comply with the requirement of the National House Building Council (NHBC) or Housing Association Property Mutual (HAPM), a minimum 50mm clear residual cavity should be provided in any exposed zone.
For buildings up to 12m high, a minimum clear cavity width of 25mm may be acceptable, subject to exposure. The 25mm minimum constructed residual cavity width must be clear of all obstructions.
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