[0001] This invention is concerned with methods of protecting and insulating existing roofs.
[0002] It is known that an existing external roof surface can be given a protective coating
by applying a flexible reinforcing sheet and brushing a membrane liquid onto that
sheet. When the liquid has set it provides a very effective water resistant surface.
Roof insulation is conventionally achieved by lining the under-surface of a roof or
the floor of a roof space with any one of a number of proprietary insulating materials.
[0003] It is an object of this invention to provide means whereby weatherproofing and heat
insulation may be applied to a roof surface at one and the same time.
[0004] Accordingly this invention provides a roofing tile formed from a plastics material
having a high density top surface and defining an underneath cavity, the cavity region
incorporating strengthening and support members and communicating with the exterior
of the tile through passageways in the top and side walls.
[0005] Such tiles may be laid over an existing roof surface and then a foam-setting insulating
material can be injected through the passageways in the top walls of the tiles, this
has the effect of bonding and sealing the tiles to the roof surface, and the foam-setting
material acts as a heat insulator as well as providing weatherproofing, at least to
some extent. Ideally the top surface of the tile will be pre-coated with a waterproofing
membrane to create a greater degree of weatherproofing.
[0006] In the preferred arrangement the strengthening and support members will be ribs dividing
the cavity into separate regions. These ribs could extend from the centre to the four
corners of a square or oblong tile to define four essentially triangular separate
cavity regions. The support members will then preferably include a central boss extending
down to the base level of the tile. Greater support can be achieved by a larger number
of radiating ribs, which need not necessarily be linked to the side walls on a central
boss.
[0007] If the side walls of the tile surrounding the cavity are so dimensioned and constructed
as to be capable of being compressed partially when pressed by a heavy roller, then
an array of tiles can be rolled so as to create a fairly even overall top surface.
[0008] It is preferred that the through passageways in the side walls should terminate in
cavities formed in the outer surface of the side walls. Excess injected foam-setting
material can then pass into these cavities to ensure the sealing of any gaps between
adjacent tiles and bonding together of adjacent tiles.
[0009] The cavity (or separate regions thereof) of the tile is ideally,defined by a top
wall surface which internally slopes upwardly from the centre to the edges of the
tile. Injected foam-setting material will then tend to expand upwardly and outwardly
to ensure spread of the foam-setting material within the cavity.
[0010] The high density top surface of the tile may be a separate sheet bonded to the remainder
of the tile formed from a lower density plastics material, or the two parts could
be formed in separate stages of a forming operation from plastics materials. In any
event part or all of the tile may be formed from a foamed plastics material.
[0011] . The tile top surface may with advantage incorporate a decorative pattern or shaping
to represent a conventional roofing tile member. The base of the tile can, if necessary,
be shaped to fit a corrugated or other non-planar existing roof surface. The tiles
will naturally need to be fixed in place on the existing roof surface and rather than
achieving this by applying an adhesive to the existing roof surface it may be preferable
to provide the under-surfaces of the side walls of the tile with a contact adhesive
which can, for example, be covered by a removable backing strip.
[0012] The invention also extends to a method of covering an existing roof surface which
comprises laying roofing tiles of this invention of the form as defined above in an
abutting side-by-side relationship and injecting a foam-setting plastics material
through the passageways in the top walls of the tiles to fill the underneath cavities.
[0013] The foamed material is ideally a polyurethane foam. Ideally the foamed material will
be injected by an injection gun set to inject a predetermined quantity sufficient
to fill the underneath cavity or separate cavity region-of one tile. The passageways
through the top walls of the tiles can be plugged with portions of dowelling formed
from polyurethane or other convenient plastics material after injection of the foamed
material.
[0014] Special tiles may be formed having a predetermined shallow pitch on the top surface
from one side to the other. A series of tiles of this type having varying thicknesses
may be laid side-by-side to define a pitch to the roof surface eventually formed by
the laid tiles.
[0015] If necessary a special central tile forming a ridge on its top surface may be used
to form a new roof surface having a pitch face sloping down on both sides from the
special ridged tile.
[0016] In an alternative arrangement spacer tiles may be provided for fixing to a roof surface
prior to the application of a standard roof tile, some at least of the spacer tiles
being formed with a predetermined shallow pitch on the top surface from one side to
the other. Additional spacer tiles of constant thickness could be used in association
with the pitched spacer tiles to achieve a build-up in height as one progresses from
one side of a proposed slope to the other. It is envisaged that the spacer tiles of
constant or pitched shape should have no enclosing top wall so that cavities will
pass directly through from the top to the bottom of the spacer tiles so as to communicate
with the enclosed cavities on the under-surfaces of the standard tiles which will
be laid on top of the spacer tiles.
[0017] The invention may be performed in various ways and preferred embodiments thereof
will now be described with reference to the accompanying drawings, in which:-
Figure 1 is an underneath plan view of a roofing tile of this invention;
Figure 2 is a vertical cross-section through the centre of the tile shown in Figure
1;
Figure 3 is a side view of an array of tiles fixed to an existing roof surface;
Figure 4 is an underneath plan view of an alternative design of roofing tile of this
invention;
Figure 5 is a vertical cross-section through the centre of the roofing tile shown
in Figure 4;
Figure 6 illustrates a modified form of roofing tile for a corrugated roof;
Figure 7 is a side view of a pitched roof structure constructed in accordance with
the invention;
Figures 8 and 9 are underneath plan and vertical sections through a preferred form
of standard tile forming the top surface of the roof structure of Figure 7; and
Figures 10 and 11 are plan and side views of a pitched tile used in constructing the
sloping roof structure illustrated in Figure 7.
[0018] The tile 1 shown in Figures 1 to 3 has a high density top layer defining a flat top
surface 2, the remainer of the tile being formed from a lower density rigid polyurethane
foamed material. Four separate cavity regions 4 are defined at the under-surface of
the tile by ribs 5 extending to the corners from a central boss 6. Each of the cavity
regions 4 communicates with the top surface of the tile by passageways 7 and also
further passageways 8 lead from the cavity regions 4 through the side walls 9. The
passageways 8 terminate in cavities 10 formed into the side wall surfaces. At the
base of the side walls 9 there is formed a contact adhesive strip 11 covered by a
removable backing strip which can be taken off on site.
[0019] When the tiles are to be used to cover an existing roof surface the backing strips
are removed to expose ihe contact adhesive and the tiles are then set out :ver the
roof surface in an abutting side-by-side :elationship. Any remaining gaps may be filled
with half or quarter tiles as required. The tiles could have fracture lines to aid
in breaking down into such smaller parts. If necessary the array of tiles may be subjected
t; the action of a heavy roller so as to create a particular roof fall and/or a generally
even surface as the side walls 9 will tend to reduce in height partially where parts
of tiles stand proud of the rest.
[0020] A polyurethane foam is then injected into each of the regions 4 through the passageways
7 and excess foamed material will pass out through the passageways 8 and into the
cavities 10 so as to bond adjacent tiles to one another. Excess foam projecting above
the surface of the tiles, as at 12 in Figure 3, can be cut off when the foam has set.
After foam injection the passageways 7 can be plugged with portions of dowelling formed
from polyurethane material. The tiles will have been pre-coated with a waterproofing
membrane as part of the original tile manufacture so that the final roof surface will
be water resistant. Thus the rigid layer 3 could be of polyvinylchloride providing
the waterproofing effect as well as acting as the high density layer. This membrane
could, if necessary, extend beyond the edges of the tile so that an overlap could
be formed onto adjacent tiles. The spaces between adjacent tiles can be brushed over
with a water resistant coating, have an adhesive waterproof strip applied, or be sealed
by heat sealing of a compatible waterproof strip, as the final stage of forming the
weatherproofed and heat insulating surface of the roof.
[0021] The modified roof tile shown in Figure 4 incorporates a preferred ribbing construction
which gives better overall support for the tile surface. Thus eight ribs 5A radiate
out from an open central area which communicates with the exterior through a central
single passageway 7. The central boss is omitted.
[0022] From the cross-sectional view of Figure 5 it will be seen the lower portion 9A of
the side walls 9 differs from the remainder of the tile, and is formed from a compressible
foamed layer of material. This allows the tile to adjust more readily to uneven surfaces
(for example a roof surface provided with chippings) in that the layer 9A will compress
where localised projections occur. This could be instead of or in addition to the
adhesive layer 11 shown in Figure 2.
[0023] A modified method of filling the cavities within the tiles utilises an open cell
flexible polyurethane foam. When set this foam will be porous and so any internal
pressure which might build up due to vaporisation of trapped moisture, for example,
can be relieved through the plug of foam in the passageway 7. Thus Figure 5 shows
a vent cap 21 positioned over the passageway 7. Passageways 7 in other tiles could
be blocked by an impervious member, such as a plug. Then if the layer 9A is also of
a porous nature, relief of pressure which might build up under adjacent tiles can
be relieved through the nearest tile carrying a vent cap 21.
[0024] A flexible under layer for the tiles, by incorporating a flexible wall layer 9A and
injecting a flexible foam, can achieve a number of desirable effects. Thus surface
pressure on the top wall of the tile is reduced (since the lower layer is compressible),
and overfill with the foam is less critical. Also a flexible layer allows for minor
roof movements (due to settlement or heat expansion) and a porous layer allows for
ventilation.
[0025] The top layer 3 of the tile may be a moulded sheet of polyvinylchloride, which therefore
acts as the waterproofing membrane. Gaps between adiacent tiles can then readilv be
covered by strips of polyvinylchloride heat sealed to the tiles.
[0026] The roofing tiles can be formed with a modified underneath surface, such as that
illustrated in Figure 6, where the tile is to be applied to an existing corrugated
roof. Other roof shapes may be accommodated in a similar manner by suitably shaped
tiles. If there should be a need or desire to apply the tiles to a roof surface with
spaces between the tiles, the tiles could be pre-formed with spacer projections as
necessary.
[0027] It will be appreciated that the tiles may readily be applied to the wall surfaces
of buildings in a manner similar to that described above. In this case the tile profile
may be pre-formed with any desired wall texture or contoured effect.
[0028] An insulating and weatherproofed pitched roof structure as applied to an existing
flat roof surface 12 is illustrated in Figure 7. This uses pitched tiles 13, spacer
tiles 14 and 15 and cover tiles 16. The cover tiles are of generally standard form
and thus (as shown in Figures 8 and 9) incorporate a flat top surface 2, cavity regions
4 defined by ribs 5 extending to a central boss 6 and passageways 8 through the side
walls 9. In this particular embodiment it will be noted that there are three passageways
8 in each of the side walls and two passageways 8 in each of the end walls. It will
also be noted that the walls 9 are slightly angled to assist the flow of foam injected
into the cavities 4 on the under-surface of the tile 16.
[0029] In this example a single passageway 17 is formed at one corner only of each tile
16 passing through one of the ribs 5. A moulded tubing member 18 passes from the passageway
17 to a junction piece 19 within the central boss 6 having outlets leading into the
cornersof each of the four cavities 4. When four of these tiles 16 are positioned
on a roof surface so that the corners incorporating the passageways 17 are adjacent
to one another it is possible to inject polyurethane foam into the cavities of four
tiles 16 simultaneously from a gun having four outlets plugged into each of the four
passageways.17.
[0030] The pitched tiles 13 (as illustrated in Figures 7, 10 and 11) have sides of 1,000mm
in length and a maximum height at one end of 35mm sloping down in one direction to
a height of 10mm at the other end. It will be appreciated that the relative dimensions
in Figure 7 have been distorted to illustrate the intended effect whilst the true
shape is more realistically illustrated in the cross-sectional view shown in Figure
11. The pitched tiles 13 are also formed with ribs 5 radiating from a central boss
6 but there is no top wall so that openings 20.are formed which pass completely through
the tile 13 which will therefore receive the foamed polyurethane injected into the
main tiles 16, in a direct manner. This applies also to the spacer tiles 14 and 15
which, in plan view, are identical in appearance to the pitched tiles 13 as shown
in Figure 10 and have the same openings 20 passing all the way through.
[0031] The spacer tiles 14 are 25mm in height whilst the spacer tiles 15 are 50mm in height.
These dimensions, together with those of the pitched tiles 13 enable the height to
be increased progressively as the height of the slope increases as illustrated in
Figure 7.
[0032] In Figure 7 it will be noted also that a special ridge tile 16A is provided which
has a slightly longer top surface so as to define an end wall which will be co-extensive
with the end walls of the pitched tiles 13 and spacer tiles 14, 15 defining the maximum
height of the pitch. A similar pitched roof structure could extend downwardly from
the top point so as to define a double pitched roof structure. In this instance, if
desired, the special tile 16A could be replaced by a tile defining a ridge with angled
surfaces leading down to both sides.
[0033] The tiles used in constructing a covering for an existing roof may be modified in
other ways. Thus, for example, tiles could be shaped to receive roof vents, double
glazed lights and moulded parapet walls enabling safety rails to be mounted to aid
future roof access.
1. A roofing tile formed from a plastics material having a high density top surface'(2)
and defining an underneath cavity (4), the cavity region incorporating strengthening
and support members (5,6) and communicating with the exterior of the tile through
passageways (7,8) in the top and side walls.
2. A roofing tile according to claim 1, wherein the strengthening and support members
are ribs (5) dividing the cavity into separate regions, which ribs preferably extend
from at or near the centre to the sides and/or four corners of a square or oblong
tile to define essentially triangular cavity regions (4), the support members optionally
also including a central boss (6) extending down to the base level of the tile.
3. A roofing tile according to claim 1 or claim 2, wherein the through passageways
(8) in the side walls terminate in depressions {10) formed in the outer surface of
the side walls (9).
4. A roofing tile according to any one of claims 1 to 3, wherein the cavity (4) is
defined by a top wall surface which internally slopes upwardly from the centre to
the edges of the tile.
5. A roofing tile according to any one of claims 1 to 4, wherein the high density
top surface of the tile is a separate sheet (2) bonded to the remainder of the tile
(1) which is formed from a lower density plastics material, with part or all of the
tile ideally being formed from a foamed plastics material, and preferably the side
walls (9) of the tile surrounding the cavity (4) are so dimensioned and constructed
as to be capable of being compressed partially when pressed by a heavy roller, such
as by providing that a horizontal layer (9A) of the side walls of the tile is formed
from a readily compressible foamed material.
6. A roofing tile according to any one of claims 1 to 5, wherein the tile top surface
incorporates a decorative pattern or shaping to represent a conventional roofing tile
member, and/or the base of the tile is shaped to fit a corrugated or other non-planar
existing roof surface, and preferably the underneath surfaces of the side walls of
the tile carry a contact adhesive (11).
7. A roofing tile according to any one of claims 1 to 6, wherein the top surface of
the tile is pre-coated with a waterproofing membrane.
8. A roofing assembly comprising roofing tiles (16) of the form as defined in any
one of claims 1 to 7, and support tiles (13,14,15) of the same shape in plan view
to the roofing tiles, at least some of the support tiles (13) having side walls which
taper from one side to the other, the support tiles ideally being open at the top
and bottom faces.
9. A method of covering an existing roof surface comprising laying tiles of the form
as defined in any one of claims 1 to 8 in an abutting side-by-side relationship and
injecting a foam-setting plastics material, such as polyurethane foam, through the
passageways (7) in the top walls of the tiles to fill the underneath cavity (4), the
foamed material preferably being injected by an injection gun set to inject a predetermined
quantity sufficient to fill the underneath cavity or a separate cavity region of one
tile, and spaces between the top surfaces of adjacent tiles are ideally covered by
a waterproofing membrane as a final step.
10. A method according to claim 9, wherein the foamed material is an open cell foam
which will produce a porous flexible filling for the tile, at least some of the passageways
through the top walls of the tiles preferably being covered by a vent cap (21), and/or
wherein passageways through the top walls of the tiles are plugged with portions of
dowelling formed from polyurethane or other convenient nonporous plastics material
after injection of the foamed material.