GB2246376A - Method of flue insulation - Google Patents

Abstract

A method of flue insulation in a building of a cavity wall type comprises panels (26) which are inserted between the flue (12) and the outer wall (16) of the cavity wall as the building is being erected. The panels comprising plates of heat insulating material completely encased in waterproof membranes. The membrane preferably comprises a metallic foil type of paper laminate which is reinforced with glass fibre. The panels are placed edge to edge on top of each other and serve to prevent moisture penetration. <IMAGE>

Description

Nethod of Flue Insulation This invention relates to a method of providing flue insulation for the flue of a building wherein the building is of the cavity wall type, and the flue is located towards the inner wall of the cavity wall, and there is an insulation space between the flue and the inner surface of the outer wall of the cavity wall.

The invention also has application to insulation materials for use in accordance with the method.

Flues of the type to which the invention relates typically are constructed from flue blocks which are placed one on top of the other during the construction of the flue, and indeed during construction of the building, so that the flue passage extends in the desired path, and the flue gases are ejected from the appropriate chimney structure. In order to prevent loss of heat from the flue, it is usual to provide heat insulation material in the narrow space between the rear of the flue and the inner surface of the outer wall of the cavity wall, but certain difficulties have arisen in that such space is relatively small so much so that moisture which passes through the outer wall of the cavity wall can in fact bridge on to the insulation, which is undesirable as dampness can be caused thereby, and furthermore the contact between the water and the insulation material can cause heat loss.

To overcome this problem, attempts have been made to introduce impermeable membranes in web form between the insulation and the outer wall of the cavity wall, but placement of such webs during building constitutes a significant difficulty, for reasons which include that the web is a relatively flexible material and it is difficult to keep it in position. Also, the web is difficult to feed into the small clearance between the insulation and the inner surface of the outer wall of the cavity wall.

The present invention seeks to overcome the disadvantages of existing methods, and provides that as the flue is being constructed, panels of insulation material are placed edge to edge on top of each other and between the rising flue and the outer wall of the cavity wall, and said insulating panels comprise plates of insulating material which are encased in a waterproof membrane applied thereto, suitably by adhesive, at a remote location and preferably under factory conditions.

It is a relatively simple matter to position the panels edge to edge on top of each other and place them between the rising flue and the inner surface of the outer wall of the cavity wall as the flue is being erected.

The said moisture impermeable material obviously prevents seepage of moisture into contact with the heat insulation plate, and in a preferred construction the panels are provided with extension skirt portions of said moisture impermeable material which are arranged at the side facing the inner surface of the outer wall of the cavity wall to overlap adjacent panels thereby making the seepage of moisture between the butting edges of the panels unlikely.

At said butting edges there may be applied a sealant material further to enhance this effect.

The extension skirt portions may be provided at two adjacent sides of the panels where the panels are of rectangular configuration. Such rectangular panels may be used with the longer dimension vertical or horizontal depending upon the width of flue to be insulated. As many panels on top of one another and indeed side by side and in appropriate disposition may be used as required.

Preferably, the impermeable membrane is also heat reflective in nature e.g. it may comprise or include a metallic foil such as an aluminium foil which on the side facing the rear of the flue, will in fact reflect heat emanating from the flue back in the direction of the interior of the building, which of course is desirable.

The invention also extends to panels for use in conjunction with the method, and preferably of each of the panels, the insulating plate is completely encased in the moisture impermeable material.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, wherein: Fig. 1 illustrates a series of flue blocks which can be used in any combination for the creation of a flue; Fig. 2 shows one example of utilisation of blocks of Fig. 1 to create a building flue; Fig. 3 is a sectional elevation taken for example on a line II-II of Fig. 2; Fig. 4 is a perspective elevation of an insulating panel utilised in accordance with the embodiment of the invention; Fig. 5 is a sectional plan of the panel shown in Fig. 4, the section being taken on the lines V-V in Fig. 4; and Fig. 6 represents a rear view of a portion of the flue arrangement shown in Fig. 2, but also showing the utilisation of the panels each according to Fig. 4 for forming an insulation layer.

Referring to the drawings, Fig. 1 shows a series or set of flue blocks with respective designations Z1, 1ZA, 2Z and so on, which are capable of being used with one another in any desired arrangement in order to create a flue in a building, and Fig. 2 shows how the appropriately designated blocks are arranged one on top of another in order to create such a flue. Fig. 2 indicates that at floor level a block of type Z1 which is a starter block is placed at floor level, and then the various blocks are positioned one on top of each other as shown. Each block apart from block 1Z is provided with a passage therethrough, and the combined passages become aligned in the resulting flue and form a flue passage 10 for the escape and discharge of flue gases in conventional manner.The flue is illustrated by reference numeral 12 in Fig. 2, and if reference is made to Fig. 3, it will be seen that the flue 12 is embodied in an inner wall 14 of a building cavity wall of which the outer wall is indicated by reference 16. Wall 16 may comprise exterior brickwork, whilst the inner wall may comprise blockwork 18 on which is applied a dry lining 20 in conventional fashion. In the cavity 22 between the inner and outer walls 14 and 16 and on opposite sides of the flue 12 is insulation material 24 of conventional construction. The width of the cavity receiving the insulation material 24 may typically be in the order of 60mm, and as the flue 12 projects slightly into that cavity as shown in Fig. 3, the remaining space between the flue 12 and the inner surface of the outer wall 16 is less than 60mm, and may typically be in the order of 30mm.It is usual to provide heat insulation between the flue 12 and the inner surface of the outer wall 16, but in the past it has been difficult to provide a moisture impermeable barrier in that space which is necessary to ensure that the insulation does not permit the moisture to migrate from the outer wall 16 onto the rear of the flue 12. In the instant embodiment of the present invention, panels 26 are inserted in the space between the flue 12 and the outer wall 16 for the complete extent of the flue 12.

Preferably, the panels are of identical configuration, and one such panel is shown in Figs. 4 and 5. Referring to these figures, the panel 26 is of rectangular configuration and comprises a plate 28 (Fig. 5) of heat insulating material which is encased in an outer membrane 30 of moisture impermeable sheet material, which is preferably adhered thereto by means of a suitable adhesive. The membrane casing 30 preferably completely encases all sides and edges of the plate 28, and at two of the edges the membrane material has overhang or oversail skips 32 and 34 which extend for the entire length of each of the sides, and which lie in the plane of one side face of the panel. These skirts are to overhang adjacent panels when the panels are fixed in position during the erection of the flue.

Fig. 6 shows how these panels might be arranged for example in the case of the flue shown in Fig. 2. Fig. 6 is a view looking at the flue 12 from the opposite direction and in the figure only the flue passage 10 is shown in the interests of clarity. The faces of the panels 26 shown in Fig. 6 will therefore be directed towards the inner surface of the outer wall 16.

The panels 26 are arranged one on top of another so that respective edges abut, and it can be seen that the skirts 32 and 34 are arranged to overhang the panel located thereunder.

As regards the lowermost panel, the skirt 32 may be tucked under the lowermost edge. The panels are basically positioned as shown in Fig. 6 in order to provide an overall insulation for the flue, and the skirts serve to prevent penetration of moisture through the abutting joints. It will be noticed from Fig. 6 that two of the panels 26 are arranged on their sides while the others are arranged upright. This is to ensure that the panels respectively cover the gathering blocks 3Z which are arranged to divert the flue passage as shown in Fig. 2.

The panels 26 are simply placed in position as the building of the flue proceeds and as many as are required can be used either one on top of another, and/or side by side, for example as indicated by reference 36 in Fig. 6, as may be required.

The main function of the panels 26 is to provide the insulation between the flue and the outer wall, but by selection of the covering membrane, the panels also form moisture barriers and an additional damp proof membrane is not required. The panels also provide fire resistance.

The materials for the panel should be selected to meet the necessary statutory requirements. Typically, the plate 28 may comprise the material known by the trade mark ROCKSIL which is a material manufactured from long, non-combustible rockwool fibres bonded with high performance binder. Such material is easy to handle and cut, and embodies high levels of thermal efficiency, acoustic absorption, strength and robustness. It is also highly fire-resistant. The material has shown itself to be relatively rot-proof and odourless; it is non-hygroscopic, will not sustain vermin and will not encourage the growth of fungi, mould or bacteria. The material furthermore is dimensionally stable under varying conditions of temperature and humidity.

The covering membrane which provides a high efficiency vapour barrier may comprise an aluminium foil/craft paper laminate reinforced with glass fibre yarn and made up of the following:9 Nicron Bright Aluminium Foil 25 GSM Polyetheline 12.5mm x 12.5 Glass Scrim 70 GSM Unbleach Kraft thickness 0.130mm Such a material has excellent fire resistance, and on the aluminium foil which is preferably to the outside of the panel there is provided a heat reflective surface and therefore the membrane provides two functions namely one of providing a moisture barrier to the side which faces the inner surface of the external wall 16, and a heat reflective surface to the side which faces the rear of the flue.

The adhesive which is used for anchoring the membrane to the ROCKSIL preferably is a non-flamable heat resistant adhesive such as SBR adhesive.

During installation the installer should ensure that the oversail skirt 32, 34 is at the bottom of the panel and overlaps the immediately adjacent underneath panel. It is also advisable to provide a bead of silicone sealant between the abutting edges of adjacent panels as this prevents relative movement and also is an added aid to prevent dampness penetration. The procedure is repeated in conjunction with the raising of the flue until the entire flue is insulated.

It is also desirable to provide wall ties to opposite sides of the panels 26 and as close to the edges of the panels as possible, as these wall ties can provide a guide means for the panel and also a means to provide lateral support for the panels and to prevent movement of same in use.

Although the panels can be made of any suitable dimension, in practical terms a panel of 1200 by 600my with a thickness of 25mm has shown itself to be particularly suitable. Each oversail skirt 32 may be in the order of 100mm wide.

Claims (12)

1. A method of providing flue insulation for the flue of a building wherein, as the flue of the building is being constructed, panels of insulation material are placed edge to edge on top of each other and between the rising flue and the outer wall of the cavity wall, and said insulating panels comprise plates of insulating material which are encased in a waterproof membrane applied thereto, suitably by adhesive, at a remote location and preferably under factory conditions.

2. A method according to claim 1, wherein wall ties are provided to opposite sides of the panels and as close to the edges of the panels as possible, so as to serve as a guide means for the panels and also as a means to provide lateral support for the panels and to prevent movement of same during installation.

3. A method according to claim 1 or 2, wherein the panels are provided with extension skirt portions of said moisture impermeable material, which are arranged at the side facing the inner surface of the outer wall of the cavity wall and which overlap adjacent panels thereby making the seepage of moisture between the butting edges of the panels unlikely.

4. A method according to claim 3, wherein the panels are of rectangular configuration, and the extension skirt portions are provided at two adjacent sides of the panels.

5. A method according to any preceding claim, wherein there is a sealant material between opposite edges of adjacent panels.

6. A method according to any preceding claim, wherein the impermeable membrane includes or comprises a metallic foil.

7. A method according to claim 6 wherein the impermeable membrane foil is also heat reflective and has a heat reflective surface to the outer face thereof on the side facing the rear of the flue. &

8. A method according to any preceding claim, wherein the laminate includes paper layer reinforced with glass fibre yarn.

9. A method according to any preceding claim, wherein the insulating material comprises a material manufactured from long, non-combustible rockwool fibres bonded with high performance binder.

10. A method according to any preceding claim, wherein the panel has size in the order of 1200 x 600mm and a thickness in the order of 25mm.

11. A method of providing flue insulation for the flue of a building wherein the building is of a cavity wall type, substantially as herein before described.

12. One or more insulation panels for use in the method according to any preceding claim.