GB2432899A

GB2432899A - Masonry chimney stack construction incorporating a damp migration limiter system

Info

Publication number: GB2432899A
Application number: GB0524381A
Authority: GB
Inventors: Barry Russell
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-11-30
Filing date: 2005-11-30
Publication date: 2007-06-06
Anticipated expiration: 2025-11-30
Also published as: GB0524381D0; GB2432899B

Abstract

A chimney stack in accordance with the invention has a damp course formed from a multiplicity of lapped watertight segments 13 each composed of a robust, firm, and durable, water-impermeable plastic sheet material. The several lapped segments which lie between adjacent brick courses each have a brick-platform portion 15 and at least one, inner, longitudinal side flange portion 15a. The majority of the segments are of channel cross-section, having a second, outer, longitudinal side flange 15b. Damp migrating through the stack from above through porosities in bricks seated upon the brick-platform portions makes wetting contact with the damp course segments, further movement of migratory damp being thereafter prevented, otherwise than by capillary action along the wetted continuous uninterrupted surface of the brick-platform portions of the several segments in a direction toward a place or places 17 of escape for such damp. The place or places of escape is/are provided by a segment, or a sequence of lapped segments, devoid of an outer side flange portion or portions 15b the brick-platform portion or portions of which are between two adjacent brick course portions provided at a stack frontal wall or walls. The invention extends, also, to a set of parts adapted to be integrated with one another such as to constitute a damp course as stated.

Description

CHIMNEY STACK STRUCTURES

FIELD OF THE INVENTION

l'his invention relates to chimney stack structures.

BRIEF DESCRIPTION OF PRIOR ART

it is standard building practice to provide building chimney stacks with at least one damp course, customarily in the form of a lead saddle tray formed along edges thereof, in the course of installation of the tray by a plumber, with upstanding and downwardly projecting edge side flange portions. l'he tray so formed is installed, such as to constitute an element of the stack, at the position where the stack penetrates, typically, a pitched roof, whether to one side of or symmetrically with respect to the roof ridge, between two adjacent courses of bricks, the tray fully spanning the stack with the upstanding and downwardly projecting flanges previously mentioned in contact with sides, respectively, of the stack, at or adjacent to the position of intersection of a frontal wall of the stack. in constructions where the stack penetrates the roof to one side of the roof ridge, there is a single frontal wall, a front apron portion of the roof leading downward from the line of intersection between the roof and the stack frontal wall. In constructions where the stack penetrates the roof symmetrically with respect to the roof ridge the stack has, of course, two oppositely facing frontal walls with a front apron root portions leading downward, respectively, from the two lines of intersection between the frontal walls and the roof. The impervious nature of the lead saddle tray limits seepage of damp through the porous bricks of the stack downwards through the roof space to the walls and other segments of the rooms beneath. Damp, instead of reaching such habitable regions of the building is, upon reaching the saddle tray, directed by the saddle tray to escape from the stack, under capillary action, between the tray and the adjacent course of brick-form elements at the tray upper surface, the discharge of any such moisture so escaping being prevented, by lead flashing, provided, also, at the j uncture between the chimney face and the roof apron forward of the chimney stack at the frontal wall or walls from regaining contact with the brickwork beneath the damp course.

The installation, as slated, of lead saddle trays is both costly and time-consuming. Apart from the cost of material, in the course of erecting the chimney stack the bricklayer must interrupt his work and await the services of a plumber to size the lead sheet, form it at its margins with up-or down-turned side flange portions, as the case requires, and to lay and adjust the tray to provide a good match with the outer edges of the stack at the position of the course. The lead worker having done this, the stack builder is then able to resume his work, laying the remainder of the brick courses required for the chimney stack above the lead saddle tray SO formed and installed.

On occasions, after installation of the lead saddle tray and completion of the brickwork, followed by the introduction of lead flashing at the junctions between the sides and, where appropriate, of the chimney stack and abutting roof covering elements, slates or tiles, and the furnishing of the stack, finally, with a concrete protective cap, penetration of water into the roof space is discovered, and a dispute not infrequently arises as to who shall be held responsible for the defect. Not infrequently, also, responsibility for the defect is found, ultimately, to lie with the lead worker, the integrity of the lead saddle tray being found to be compromised due, perhaps, to a fracture introduced in the tray the course, for example, of the formation by the lead worker of the peripheral lianges of the tray. Not infrequently, the stack having been constructed.

discovery of a defect at the lead saddle tray entails dismantling the work of the builder hack to the defective saddle tray, a costly and time consuming procedure.

A further adverse characteristic of chimney stack structures incorporating lead saddle trays as their damp course arises from the de facto partition of the stack into two segments, the one above, the other below the saddle tray. There being no mortar bonding between bricks at any place along the two courses adjacent to one another at the position of the saddle tray, it is not unknown, particularly when the saddle tray upper surface is wetted repeatedly from moisture percolating down the stack, for slippage to occur between the stack portions, perhaps progressively, over an extended period, under, for example, the continuous battering of the stack by high winds. It might, with some justice be said, that the customary building practice is, in this respect, an unsatisfactory one.

It would certainly he a great deal more satisfactory if instead of two workers, the bricklayer and the lead worker, the erection of the chimney stack remained, throughout, in the hands of a single person, in particular the bricklayer, and it is the object of the present invention to propose a novel form of chimney damp-migration limiter means by which this may be achieved.

Using the invention to be described hereinafter, the bricklayer is enabled not only to practice his brick-laying craft, but in the course of his work, without special skills, to install the novel stack damp-migration limiter means, also, a damp limiter means which, in contrast with lead saddle tray installations, is not readily susceptible to damage capable of admitting water seepage through the POFOUS bricks of the chimney stack through the roof space to the walls and other segments of rooms below, and which, moreover, admits of bonding between at least some of the hrick-fbrm elements of adjacent courses between which the damp course is introduced.

Whilst tbr most stack constructions one damp course only iieed he provided, in sonic circumstances, such, for example, as large chimney structures, a second leas saddle tray constituting a secondary damp course may also he integrated with the brick courses to form the stack. The secondary damp course is installed between adjacent courses at a higher level of the slack. Whereas the primary damp course deflects damp to a forward roof apron, the secondary damp course deflects damp seeping through porosities of the brickwork from above to emerge from the damp course at the edges of the secondary damp course, such emergent damp dripping from and otherwise dispersed at downward flanges of the secondary lead saddle tray. Damp gaining access to brickwork beneath the secondary damp course and eventually reaching the primary damp course is linally, upon emerging at the frontal wall, discharged to the Ibrward roof apron.

SUMMARY OF FEATURES OF THE INVENTION

In accordance with the invention, a masonry chimney stack incorporating a damp migration limiter system comprises: a multiplicity of segments composed each of a robust, firm, and durable, water-impermeable sheet material, each said segment having a substantially flat longitudinally extensive brick-platform portion of width not substantially greater than the width of at least one brick-form element of the stack and a side flange portion (hereinafter "first side Ilange portion") upstanding from said brick-platform portion along one of the side edges thereol the segments being constructed such and being lengthwise serially arranged with respect to one another between adjacent brick courses such that successive segments are in lapped relationship with each other, with the several said segments collectively encompassing the stack wall; and in which: among said segments some are of channel Rrm, being formed each with a second side flange Portion upstanding along the other of the side edges of the brick-platform portion thereof said first side Ilange portions of all said segments projecting upwards adjacent to the inwards-facing surface of the stack wall, and said second side flange portions of said channel-form segments projecting upwards adjacent to the outwards-facing surface of the stack wall; and, * means adapted to produce a watertight seal between lapped portions of the several segments such as to integrate the several segments to provide a continuous uninterrupted surface; and in which: * channel-fhrm segments are disposed with the brick-platform portions thereof between brick runs of adjacent courses, being brick runs extending along at least the side walls of the stack and along at most one of the two opposite frontal walls of the stack, and segments devoid of said second side flange portions are disposed with the brick-platform portions thereof between brick runs o adjacent courses, being brick runs extending along at least one of said stack frontal walls; and, * the construction and overall arrangement of the several said segments and the watertight lapped relationship therebetween, is such that the several segments cooperate to provide, through the stack, an uninterrupted water-impermeable path serving to constrain such damp as may migrate by way of brick porosities downwards of the stack from above to the locations of the segments thereby to make wetting contact with said segments, further movement of migratory damp being, thereafter, prevented, otherwise than by capillary action along the continuous uninterrupted surface of the brick-platform portions of the several segments in a direction toward a place or places, as the case may be, of escape for such damp, said place or places of escape being provided by a segment or a sequence of lapped segments devoid, as aforesaid, of a second side flange portion or portions, as the case may be, the brick-platform portion or portions of which are between two adjacent brick course portions provided at a stack frontal wall or. as the case may be, respective ones of the stack frontal walls.

l'he foregoing and other features of masonry stack constructions in accordance with the invention are hereinafter described with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a pictorial diagram showing a transverse longitudinal section through a portion of' a chimney stack of a construction in accordance with the invention; Fig.la is a scrap diagram of a detail of the chimney stack of Fig.l; Fig.2 is a pictorial representation of part of a first chimney stack construction in accordance with the invention, being a stack construction which penetrates a pitched roof to one side of' the ridge of the roof and which incorporates a damp migration limiter system appropriate to such a stack construction; Fig.3 shows an exploded view of the embodiment of Fig.2; l'igs.4a and 4b show perspective generally forwards facing views of co-operable left-and right-hand back segments, respectively, of the damp course of Figs.2 and 3; Fig.5a and 5b show perspective generally frontal views of co-operable right-and left-hand ftrward segments, respectively, of the damp course of Figs.2 and 3; Figs.6c and 6d show perspective generally rear views of the right-and left-hand 1brward segments, respectively, of Figs.5a and 5h; Figs.7a and 7h show perspective views of bridging segments for left-and right-hand brick courses, respectively; Fig.8 shows a perspective view of a one brick-length standard extension segment; Fig.9 shows a perspective view of a cover member for the top of the stack damp course; Fig. I 0 shows part of a second chimney stack construction the chimney stack of Fig. 1 0 at a second stage of its construction incorporating a variant damp migration limiter system appropriate to said second stack construction, the exploded view being of the stack at an initial stage of its construction; Fig.l 1 shows an exploded view of the part of' the second chimney stack shown in Fig.l0.

A l)ESCR1PTION OF CHARACTERISTIC FEA'I'URES OF TWO EMBODIMENTS OF THE

INVENTION

For purposes of the ensuing descriptions, and as outlined previously, a chimney stack 11 of rectangular cross-section has two laterally opposite stack walls, A and B, respectively, hereinafter referred to, each, as a "stack side wall". In both of the embodiments hereinafler described, the two other stack walls, C and D, respectively, are each referred to, indifferently, as a stack frontal wall". In the first embodiment (Fig.2) to be described, the stack 11, penetrating, as it does, the pitched roof of a building to one side of the roof ridge, the frontal wall C which makes an obtuse angle with respect to the pitch angle of the roof is referred to as the "stack frontal wall". In the second embodiment (Fig. 10), the stack 11, penetrating the roof at the ridge level, the stack walls C and D, both of which make obtuse angles with the roof pitch angle at opposite sides of the roof ridge line, are each referred to, indifferently, as a "stack frontal wall".

Lead flashing F1 fornis a protective closure member between the side walls A and B of the stack and edges of roof cladding members, e.g. slates, as S. and, in the embodiment of Fig. 1, lead, so-called, back step flashing F2 performs a corresponding function at the rear-fhcing wall D of the stack.

As illustrated in Fig. 1, the four stack walls A, B, C, and D, respectively, each have an outer leaf L1 incorporating a damp migration limiter system, commonly, and for brevity, hereinafter referred to as a "damp course", being a damp course as hereinafter described, and a next closely adjacent inner leaf L2, of corresponding rectangular form, which may also be of brick-form elements, or which may comprise a clay liner. In all figures, except Fig.!, the outer leaf L1 only of brick-form elements, is shown in connection with the embodiments of Figs. 1 and 2, and of Fig. 1 0, respectively.

In any and all embodiments of the invention, the damp course, comprises a multiplicity of segments 13 each composed, as previously indicated, of a robust, firm, durable, water-impermeable plastic sheet material, the segments differing in length and shape, as shown in Fig.2, the number of segments 13 being determined, essentially, by the overall length of the outer leaf L1 ofthe stack II.

Each segment 1 3 has a substantially flat longitudinally extensive brick-platform portion 15 of width not substantially greater than the width of the brick-form elements of the outer leaf L1 of the stack I I and a first, an inner, side flange portion, as I Sa, upstanding perpendicular to the brick-platform portion 1 5 along a side edge, as 1 5' of the brick-platform portion 1 5. Among the segments 13 some, hut not all, are of channel shape, whether of elbow form, as I 3a, I 3h, or of undeviating straight channel form, as 13c, I 3d, the channel form of all such channel shaped segments being formed, each, with a second, the outer, side flange portion, as I Sb, upstanding perpendicular from the brick-platform portion 1 5 along the other 15' of its two side edges.

The damp course segments 13, channel-form or not, are all disposed with their brick-platform portions 1 5 between adjacent courses of brick-form elements of the stack outer leaf L1, the inner side flange portions I 5 of all of the segments 13 projecting upward closely adjacent to an outward-facing surface of the inner leaf L2, of the stack 11. Segments 13 of channel form, extend along the outer leaf L1, at least, of the side walls A and B of the stack 11, with the second, outer, side flange portions 1 Sb projecting upward closely adjacent to the outward-facing surfaces of the outer leaf L1.

In the embodiment of Fig.1 and 2, but not iii the embodiment depicted in Fig.l0, segments of channel-form extend not only along the side walls A and B of the stack 11 but, as shown, along the stack rear facing wall D, also, the channel-furm segments so extending being constituted as arms of the elbow-form channel segments 13a, l3h.

In both embodiments, segments 13 disposed between adjacent courses of the outer leaf L1 such as to extend, in the embodiment of Fig.2, along the frontal wall C and, in the embodiment of Fig. 10. along both of the frontal walls C and D, are devoid of' outer side flange portions I Sb, and have, instead, downward dependant lip flanges, as 1 7, the lip Ilanges projecting forward slightly prominent from the adjacent brick form elements such as to overlap the lead flashing F between the flanges F3 and the roof apron forward of the frontal wall A, the lip flanges 1 7 being.

secured by fastener elements, as 19, to the adjacent brick-form elements to the rear of the hashing F the lip flanges 17 and being supported away from the flashing by suitable washers 21 interposed along the fasteners 1 7 between the flanges 17 and the brick-form elements.

Particular attention should be had to the character of segments of the damp course such, for example, as segment I 3c. As may be observed, the channel-form segments, as I3c, has a further flange portion, being an end flange portion I Sc, of generally brick-form element height, upstanding from the brick platform portion 15 of the segment 13, the flange portion 15c being adapted be interposed between adjacent end surfaces I 9a, 1 9b, of consecutive brick-form elements along a course such as to provide a surface enabling damp to migrate from a brick platfbrm-portion I 5 of a segment 13 within a brick-form course above, to the brick platform-portion IS of the channel form segment I 3c, of' which the end flange portion 1 Sc is a part.

located within the brick-ftrm course next below.

It should be noted, also, and as shown in Figs. 1 and 2 and in Fig.10, that the inner side hiange portions I Sa of the segments I 3 differ in height from the outer side flange portions I 5b. More particularly, it is to be noted that whilst the outer side flange portions 1 Sb of the segments 13 seated upon the intermediate one of the three courses of brick-form elements associated (as shown) directly with the segments of the damp course, are of lesser height than that of the brick-form elements, the inner side flange portions I 5a are of the same height as the brick-form elements. Whilst the outer side flange portions I Sb of the segments 13, which are seated upon the lowest of the said three courses of brick-form elements are, also, of lesser height than the brick-form elements, the inner side flange potions 1 5a of the segments 13 last referred to are of twice the height of the brick-form elements. The reason for this arises from the fact that whereas the inner side flange portions iSa of the brick-support platforms 15 ol segments 13 resting upon the intermediate course, shown in Fig.3, of brick-form elements, are required, by abutment, to protect adjacent brick-form elements at one course only of the inner brick-fOrm leaf L2 of the stack II against migration of damp from the outer leaf L1 of the stack wall, inner side flange portions I 5a of segments 13 resting upon the lower of the courses shown, are required, by abutment, to protect against the migration of damp, not only brick-form elements of the outer leaf L1 but brick-form elements of the intermediate course of the outer leaf L1 also. Effectively, ihe inner side flange portions iSa of the several segments form a continuous vertical water-tight screen between the courses occupied by the damp course. In stacks of still larger cross-sectional size, the damp course may span one or even more further courses of brick-form elements. In such circumstances, the channel-form segments 13 would include, among others, segments the inner side flanges ISa of which are of height three and more times, as the case niay be, times the height of the brick-form elements.

l'he damp course being fabricated from a multiplicity of individual segments 13, as aforesaid, in order to ensure the integrity of the course, means must, of necessity, be provided to ensure a watertight seal between the segments 1 3 at their lapped end surfaces. This, as shown, may he achieved, conveniently, using a double sided adhesive bonding strip, as 23, at the lapped ends of adjacent segments 13.

A rectangular sheet 25 of water-impermeable substantially rigid plastic sheet material (Figs.2 and 10), is formed, centrally, with an upstanding wall 27 extending around a rectangular aperture through the sheet aiid through which passes a flue pipe (not shown). The dimensions of' the sheet arc such that, with the sheet lying with its margins in contact with brick-form elements of' a brick course, the edges ol' the brick-form elements are outwardly beyond the edges of the sheet 25. l'he sheet 25 being of lesser dimensions than the leaf L1, bricks of the courses around the margins oI'the sheet 25 may be mortar bonded together in the course of construction of the stack.

l'he construction and overall arrangement of' the several segments 13 making up the damp course, and the lapped relationship between the segments is, in all cases, such that the segments I 3 cooperate to provide, through the stack 11, an uninterrupted water-impermeable path serving to constrain such damp as may migrate by way of brick porosities downwards of the stack 11 from above to make wetting contact with the water-impermeable segments 1 3, further movement of migratory damp being, thereafter, prevented, otherwise than across the wetted surface of the water-impermeable segments 13 in a direction toward a place of escape ftr such damp to the environment, such place of escape for damp being provided by a segment I 3d, or a sequence of lapped segments I 3d devoid, as intimated, of a second side flange portion I 5b or, as the case may he, second side flange portions, the brick-platform portion or portions 1 5 of which are between two adjacent brick courses 17a, 17b, provided at the stack frontal wall C. Figs.4a to 9 show, in greater detail, the forms given to the several segments employed in the two embodiments of Fig.2 and Fig.l0, respectively, the several segments depicted being the component parts of a set of parts for use in the construction by of a chimney stack damp course, by a bricklayer when erecting a chimney stack. It is to be understood that, subject to the requirement that the segments are to cooperate, as previously described, in the production of a stack damp course of integrity, in accordance with the teaching contained herein, the individual segments of the set may differ, as regards, for examples, length and number, from that shown and/or as described hereinbefore. The surface of the brick-support platform portions of the segments is deliberately made rough, this to enhance migration of damp along the channel-form and other segments 1 3 under capillary action. Conveniently, the roughness may be given by granular material, coarse sand S, for example, adherent to the brick-support platform portions I 5.

As previously stated, the chimney stack structure of Fig.10 rises from the roof symmetrically with respect to the roof ridge. The primary difference to be found between the structure of Fig. 1 0 and that of Fig.2 and 3 is the presence of two corresponding places for the escape of damp, each place being essentially the sanie as that shown and described with respect to Fig.3. one at each frontal wall A and B, respectively, of the stack. As may be seen, the component segments 13 of' the second embodiment, Fig. 10 and 11 of the invention are essentially the same as those hereinbefore described in connection with the embodiment of Figs. I and 2.

It may he that, for chimney stacks of relatively small height and/or cross-sectional dimensions, the several end-lapped segments of the damp course may safely be accommodated between two adjacent brick courses of the outer leaf L1 In such an event, segments, as 13c, are not called for and may he omitted from the set of parts. Although this necessarily means that the stack I I is partitioned with the courses at the site of the damp course devoid of a mortar bond, the lesser size of the staek may be sueh that the lack of mortar bonding may pose a lesser problem than were the stack of larger size whilst the benefits of ease and simplicity of stack construction are observed. -Il-

Claims

CLAIMS

1. A masonry chimney stack incorporating a damp migration limiter system, being a system which comprises: a multiplicity of segments composed each of a robust, firm, and durable, water-impermeable sheet material, each said segment having a substantially flat longitudinally extensive brick-platform portion of width not substantially greater than the width of at least one brick-form element of the stack and a side flange portion (hereinafter "first side flange portion") upstanding from said brick-platform portion along one of the side edges thereoI said segments being constructed such and being lengthwise serially arranged with respect to one another between adjacent brick courses such that successive said segments are in lapped watertight relationship with each other such as to constitute a continuous uninterrupted surface, with the several said segments collectively encompassing the stack wall; and in which: * among said segments some are of channel form, being formed each with a second side flange portion upstanding along the other of the side edges of the brick-platform portion thereof, said first side flange portions of all said segments projecting upwards adjacent to the inwards-fhcing surface of the stack wall, and said second side flange portions of said channel-form segments projecting upwards adjacent to the outwards-facing surtlice of the stack wall; and in which: * channel-form segments are disposed with the hrick-platfbrm portions thereof between brick runs of adjacent courses, being brick runs extending along at least the side walls of the stack and along at most one of the two opposite frontal walls of the stack, and segments devoid of said second side flange portions are disposed with the brick-platform portions thereof between brick runs of adjacent courses, being brick runs extending along at least one of said stack frontal walls; and, * the construction and overall arrangement of the several said segments and the lapped relationship therehetween, is such that said segments cooperate to provide, through the stack, an uninterrupted water-impermeable path serving to constrain such damp as may migrate by way of brick porosities downwards of the stack from above to the locations of said segments thereby to make wetting contact with said segments, further movement of migratory damp being, thereafler, prevented, otherwise than by capillary action along the wetted continuous uninterrupted surface of the brick-platform portions of the several segments in a direction toward a place or places, as the case may he, of escape for such damp, said place or places of escape being provided by a segment or sequence of lapped segments devoid, as aforesaid, of a second side flange portion or, as the case may be, second side flange portions, the brick-platform portion or portions of which arc between two adjacent brick course portions provided at a stack frontal wall or, as the case may be, stack frontal walls.

2. A chimney stack as claimed in claim I in which said first side flange portions are of height not less than the hrick-fbrrn elements.

3. A chimney stack as claimed in claim 2 in which several said channel-form segments comprise segments the height of said first side flange portions of which are a multiple of substantially the height of the brick-form elements of the stack.

4. A chimney stack as claimed in claim 1, 2 or 3 in which: brick-platform portions of' the several said channel-form segments are located between adjacent ones of a multiplicity of brick courses along each of the two side walls of the stack, and where, at any location between the two frontal walls of the stack, a channel-form segment, the brick-plattbrm portion of which is between a brick course and the next higher course overlaps a channel-form segment the brick-platform portion of which is between said brick course and the next lower course, said upper channel-form segment has its rear end closed by an integral wall portion, said integral wall portion having an extension upstanding proud o[the lateral side flange portions of said channel-form segment, said integral wall portion and its extension intruding between an end of a brick residing in said next lower channel-form segment and a brick adjacent thereto along the same brick course, and being of shape and size such as to constitute a vertical partition serving to isolate the segment of the course to one side of said adjacent brick-form elements from the segment to the other.

5. A chimney stack as claimed in claim 2, 3, or 4 in which the brick-form elements of the stack lies in courses not less than one brick deep in a direction inwardly towards the longitudinal axis of the stack, and in which: interposed within the course between the brick-form elements residing in said uppermost channel segment and the next higher course, a body of sheet material formed with an opening therethrough adapted to accommodate a flue pipe, said body of sheet material being composed of a robust and durable water-impermeable material and being of a shape and size such as substantially fully to span the cross-sectional area of the stack at the location, as aforestated, of the sheet material along the stack.

6. A chimney stack as claimed in any preceding claim in which the several segments are held in water-tight relationship with one another at positions of overlap by means of double sided adherent sealing strips disposed between lapped surfaces of adjacent said segments.

7. A chimney stack as claimed in any preceding claim in which the upwards facing surfaces of the brick-platform portions of the several segments have a rough surface such as to enhance flow of water therealong under capillary action.

8. A set of segments adapted to be integrated together such as to constitute a chimney damp course for a chimney stack as claimed in any preceding claim.

9. A set of segments adapted to be integrated together such as to constitute a chimney damp course tir a chimney stack substantially as hereinbefore described with reference to Figs.4a to 9.