GB2435052A

GB2435052A - Renovation for porous roof surfaces

Info

Publication number: GB2435052A
Application number: GB0602890A
Authority: GB
Inventors: Malcolm Gordon Victory
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-02-14
Filing date: 2006-02-14
Publication date: 2007-08-15
Anticipated expiration: 2026-02-14
Also published as: GB0602890D0; GB2435052B

Abstract

The present invention provides a method of applying liquid chemicals to a porous roof with the aim of the chemicals saturating the body of the tiles before hardening to create a barrier impervious to rainfall that can be expected to last for ten years or more, thus obviating the need for a new roof structure. The treatment is equally applicable to concrete and other roof surfaces, whether of slate, clay, concrete, fibre-cement or other tile material and to differing profiles, e.g. Roman, Pantile or plain, and may be applied to other absorbent roofing materials such as corrugated fibrocement sheeting wood, or thatch. The substance may comprise an epoxy ester resin in a naptha petroleum base (tarpentine) or a water based member of the polyvinyl acrylate family.

Description

1/18 2435052

TREATMENT AND METHOD FOR RENOVATION OF POROUS ROOF

SURFACES

This invention relates to the weather and rain proofing of roofs, particularly those that have become porous due to age or weathering.

The background to the invention is that in relation to the standard western domestic pitched roof construction, certain types of roof tiles become porous due to age or weathering, occasioning dampness on the inside of the roof space. This has been found to lead to problems caused by water reaching the fabric of the building.

A good example is of a brick red fibre-cement material that is interchangeable with slate tiles, used in the 1920's and 1930's. Having been in service for over sixty years, the material often loses its resilience and permits water to permeate through its body to the other side. If this is the case, problems are likely to occur in connection with the damp gathering on the underside of the tiled roof, and in severe cases the dampness can be transmitted to the fabric of the building, e.g. by affecting the battens, joists or even affecting the plaster and decoration on the inside of the building through contact with the upper surface of the walls. In this latter case the damp can transfer from the underside of the roof surface onto the top row of bricks and over time migrate downwards to loosen the plaster from the walls, especially at high level in walls of the upper floor. It is also likely to cause a bloom to occur on the surface of the plaster where the calcium of the plaster is leached out by the action of the damp as it emerges on the decorated wall surface to be evaporated by the warmer air. All of these adverse effects are undesirable, and with the only remedy 2/18 being to replace the tiles of the roof, the problem is both highly costly and time consuming.

Preparations have for some time been available to harden ageing brick and mortar, thus bringing old buildings back into condition or to provide a solid substrate for new exterior paint. No formulations or chemicals have appeared in my searches that are applied to the instant problem of bringing roof tiles back into good repair.

However, one reference appeared in the Abstract of CN1557850 YANG: "Organosilicon is used in modifying acrylate polymer to raise the water resistance, adhesion, antifouling property, anti-cracking property, etc. of acrylate paint. The emulsion has the monomer components including organosilicon monomer 4-15 wt%, unsaturated olefin acid monomer 1-15 wt%, and acrylic acid monomer 80-95 wt%.

The organosilicon modified acrylate polymer emulsion has not only the excellent characteristic of organic silicon resin, but also excellent stability, with the storage period being as long as one 0.5 year. The present invention is suitable for use as inner and outer wall decorating paint, and may be used also as building waterproof material, sealing glue, roof repairing material, etc." This appears to be a modification of an existing acrylate paint, probably as a surface covering, especially where applied to roofs, presumably other than tiled roofs, i.e. flat or prefabricated. The instant invention may utilise a number of chemicals individually or in combination dependent on the nature of the tile to be treated, and the substance referred to may be useful in the application of the invention and method. However, different chemicals have been tested and found to be effective without the use of the above mentioned organosilicon acrylate polymer. 3/18

The method of applying the chemicals to the roof to be treated is simpler than re-roofing a building, where full scaffolding is essential, and the work involves the removal and replacement of several tons of tiles. This will involve one or more skilled workers for over six man-weeks and increases the amount of spoil going to landfill; which is an increasing problem and for which the local authorities in Britain are penalised by the Landfill Tax.

According to the present invention there is provided a method of applying liquid chemicals to a porous roof with the aim of the chemicals saturating the body of the tiles before hardening to create an impervious barrier that can be expected to last for ten years or more, thus obviating the need for a new roof structure. The treatment is equally applicable to concrete and other roof surfaces, whether of slate, clay, concrete, fibre-cement or other tile material and to differing profiles, e.g. Roman, Pantile or plain, and may be applied to other absorbent roofing materials such as corrugated fibrocement sheeting or wood.

Access to the roof area is assumed, but due to the nature of the method the provision of access does not necessitate full scaffolding of the building, which is both costly and intrusive. The treatment may be achieved from a ladder or independent scaffold tower, although it has been found that a roof ladder is useful in preparing the tiles and for access to areas that are difficult to access such as those in the vicinity of dormer widows, chimneys etcetera. Given such access, using minimal equipment the treatment may be achieved. It is, however, necessary to use protective gloves and clothing, an effective face mask and goggles whenever dealing with chemicals and sprays. 4/18

Ideally, the surface of the tiled roof will be scraped or cleaned to remove foreign growth and dirt prior to the chemical application. This may be achieved in a number of known ways such as scraping, brushing or abrading with or without chemical detergents as determined by the specific roof. An application of fungicide may then be applied mixed one part of fungicide to two parts of water. However, these parts of the process are by no means essential, and ancient roofs with their flora need not be aesthetically undermined by the process. With suitable care, the chemicals may be applied in such a way that extraneous flora, algae etcetera may be retained without impairing the effect of the treatment. Any broken, loose or otherwise substandard tiles should be replaced. Any loose or substandard rendering or gaps in the rendering at the edges of the tiled surface or between tiles should be filled with an appropriate cement mix. Once the roof is prepared to the desired condition, the treatment may commence. Wherever possible, the roof should be dry, and application should not be attempted in poor weather as the liquid treatment can only penetrate as deeply as the porosity of the tile allows, and residual moisture will limit the depth of penetration. Likewise rainfall between layers of the treatment will inhibit the effectiveness of said treatment, as will high wind which will make control of the spray difficult. Moreover, the environmental temperature should not be below 5 degrees Centigrade or the relative humidity above 80%.

While in no way limiting the range of suitable chemicals it has been found that a mixture of one part of proprietary stabilizing solution to three parts of white spirit is effective in thinning the stabilising solution adequately to enable its absorption deep into the tile structure and render said solution sufficiently fluid to spray. Stabilising 5/18 solution is an epoxy ester resin compound in a Naphtha petroleum base. White Spirit is also known as High Flash White Spirit or Stoddard solvent in the USA. The most common variety of white spirit is a mixture of saturated aliphatic and alicyclic C7-C12 hydrocarbons with a content of I 5-20%(by weight) of aromatic C7-Ci2 hydrocarbons and a boiling range of 130-230 C. The liquid is thin enough at this concentration to be sprayed from a typical garden spray, although more complex spray units may be used. The advantage of the lightweight, manually pumped garden spray lies in its simplicity and portability, enabling the liquid to be sprayed into virtually inaccessible areas. In general, the pressure generated is adequate to reach the apex of the roof from the gutter line. Thorough mixing of the solution is vital and should be undertaken in a separate mixing vessel prior to charging the reservoir of the spray unit. At low temperatures the stability of the solution is not dependable, and the solution in the spray reservoir may need to be agitated if being used at low temperature, e.g. in winter. The liquid may also be brushed on, generally using a mixture of one part stabilising solution to two parts white spirit, and generally towards the edges of the roof surface or in tight areas where spatter is not desired.

Any areas requiring particular care such as skylights and flush windows should be masked with polythene sheet and secured with tape or similar. It is worth noting that the residue of the solution used in the treatment is clear and virtually undetectable except on glass, where it appears as a slightly tan translucent stain that is easily removable with solvent or a sharp edged scraper.

Once the treatment has begun by spraying along a section of the roof line, the roof pitch facing the operator should be treated in vertical strips, and each strip will 6/18 typically comprise 3 to 4 metres, so that the roof surface of the strip being treated will be thoroughly wetted, working from side to side in 3 to 4 metre strokes. It will be found that the liquid begins to run off as the roof material reaches its limit of absorption, and spaying should be halted while the run-off is absorbed when nearing the lower portion of the roof, e.g. near the gutter line. The surface may then be completely treated by spray or brush. It should be noted that tiled roofs are generally laid with a significant overlapping section of each row of tiles covering a matching underlapping section of the next lowest tile or row of tiles, and treatment should be extended into these underlapping areas as far as possible. As a result, care should be taken to ensure that the treatment affects the underlying tiles, and the treatment should be directed towards the vertical and horizontal gaps between tiles in the roof surface. An hour should then be allowed before repeating the procedure. This is an approximate measure varied by the specific material, temperature and weather generally, making a balance between saturation of the material and hardening of the chemical treatment. In general, it is best for the treatment to be continued while the surface is still tacky.

It will be noticed that the rate of absorption is less than on the first coat, showing that the permeability of the tile is decreasing as desired. A third and subsequent coats may be applied, again allowing about an hour between coats, with a theoretical maximum of 16 hours between coats. It has been found that usually three coats is sufficient to completely permeate the tile material, although this varies with different tile formulations. When the operator is satisfied that the limit of absorption has been reached, the working platform should be moved to the centre of the next 3 7/18 to 4 metre section of roof, while the method is repeated. If at any stage the treated area begins to show a glossy finish rather than a matt finish, the treatment is already completed and further treatment should not be attempted. The treatment should be continued section by section until the roof side has been completely treated. Areas such as gables and dormers should be treated contemporaneously with the section of roof in which they are situated unless practical considerations dictate otherwise.

The other side of the roof pitch or other separate areas of roof tile such as single storey roofs can then be treated in the same fashion. While the above method has been applied exclusively to tiled roofs the treatment may be applied to other roof surfaces, but this depends upon the specific instance; for example the treatment should not be used over bituminous roofing felt, but could be applied to an otherwise untreated concrete roof slab or a fibrous corrugated roof construction.

Other potential chemicals for treatment of certain types of roofing material include a water-thinnable, solvent free silicone and siloxane emulsion, a 1-10% texanol ester alcohol mixture, and a water-soluble polyvinyl acrylate solution although this list is by no means exclusive. Such compounds act more slowly; giving the highly aromatic solution first herein mentioned an advantage in terms of permeability and speed of application. However, it has been noted that an ideal treatment for a given tile may require layers of differing compounds for optimum water resistance and durability. For instance, a layer of polyvinyl acrylate over two layers of the above described mixture of stabilising solution and white spirit may increase the durability of the treatment over the long term. However, once the treatment shows signs of deteriorating with age, it is a simple enough matter to treat 8/18 it once again, once more lengthening the life of the existing roof, with all the attendant benefits.

While the invention has been disclosed in its preferred form, it is to be understood that the specific embodiment thereof, as described and illustrated herein, is not to be considered in a limited sense, as there may be other forms or modifications of the invention which should also be construed to come within the scope of the appended claims.

The invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows the essential features of the invention; Figure 2 shows the typical sequence of application of the treatment; Figure 3 shows a typical tile in cross section and the effect of water thereon; Figure 4 shows a typical tile in cross section and the effect of the treatment thereon; Figure 5 shows the typical overlay pattern of roof tiles and areas requiring particular attention.

Referring to the drawings, Figure 1 shows a typical European two-storey detached or semi-detached house as viewed from the flank wall. The tiled roof surface I has been shown to be passing water through to the inside, and therefore requires either replacement or treatment by means of the present invention. In this 9/18 instance the right hand side of roof surface 1 is chosen to be treated first, leaving the left hand side of the roof surface 8 to be treated afterwards. Means of access to the roof are required; in this case the minimum requirement is a ladder 2, although a scaffold tower or full scaffolding may be used. Said access will enable the operator 3 to treat the roof with a spray unit 4 containing the chemical treatment which is the subject of the present invention. In its simplest form, the spray unit 4 need only be of the hand-held garden spray type, although more sophisticated means such as electrically or mechanically powered compressors and spray units are not herein excluded.

A roof ladder 5 may also be provided to improve access to the higher parts of the roof surface 1; particularly to areas difficult to access 6 e.g. adjacent to chimney stack 7. Separate areas of tiled roof 9 should be treated in addition to the main roof even if they show no immediate signs of structural failure or porosity. Areas of flashing 10 around upstands such as chimney stack 7 or other irregular features may be treated integrally with the main roof structure but may occasionally require masking. When treating such areas of flashing 10 or masking the operator 3 should beware of the lack of absorption and consequent rapid run-off of the chemical solution. This may tend to accumulate in the gutter 11 and should not be allowed to follow the drainage path down into the sewer or soakaway provided. The gutter 11 should be lined with absorbent material to prevent this occurrence, and downpipes 14 likewise sealed at their junction with the gutter 11. Care should be taken with the ridge 12 of the roof when placing the roof ladder 5 in order not to dislodge the capping of said ridge 12. The roof ladder 5 is set in place by pushing the roof ladder 10/18 up the face of the roof surface 1 using its wheels 19 for assistance until said wheels 19 contact the ridge 12 at which point the roof ladder 5 is turned over in order that its head may contact the other side 8 of the roof surface in order to secure the roof ladder 5 against ridge 12 and roof structure 1. The condition of the bargeboards 13 should be checked for problems, as should the soffits and associated woodwork (not shown). The operator 3 will then perform any preparatory tasks on the roof surface 1 such as scraping, brushing, cleaning or treating with fungicide prior to filling the spray unit 4 with the chemical solution and preparing to treat the roof surface 1.

Care should be taken in mixing the chemical solution to the correct viscosity for spraying, and ensuring that the heavier resin elements have not coalesced and separated from the lighter solvent fluid. If this happens the spray will not be effective, and a syrupy liquid will emerge from the nozzle of spray unit 4. This will not be absorbed into the roof structure I and should be collected in a separate container for later re-use. Treatment should be suspended at this point while the thick fluid is removed from the spray equipment. It may be removed in the following way. If the solution is again agitated the heavier elements will be once more suspended in the carrier fluid and the whole solution thin enough to spray without problems. If the nozzle of spray unit 4 is directed into a separate container as aforesaid, the thick liquid will be forced from the nozzle and replaced by liquid at the correct viscosity. At this point the treatment of the roof may resume, and the separate container placed aside for re-mixing. The separation described is not usually a problem except in cold weather, or when the correct mixture has not been achieved. As hereinbefore 11/is mentioned, protective clothing and breathing protection should be worn by the operator 3 prior to application, whether by brush or by spray 4 or by other means.

Figure 2 shows the typical sequence of application of the treatment as applied to a dwelling having an average sized roof, being of the 3-bedroom detached or semi-detached variety. A section 18 of the roof surface I should be selected for treatment, as shown by dashed line 17, being typically about 3 metres wide for ease of application. The guttering 11 should be lined with absorbent material and the junction with the rainwater downpipe 14 likewise blocked with absorbent material to prevent fouling of the drainage system. Difficult areas to access 6, e.g. above the chimney stack 7 and at the lateral edges of the roof may be treated by brush or other convenient means in order to avoid excess spray or spatter. The spray unit 4 (not shown here) will normally be able to reach the ridge 12 of the roof surface 1 of such a dwelling from the gutter line 11 if charged to 40 PSI (pounds per square inch) and the nozzle adjusted to a continuous jet. The nozzle may be adjusted to provide a finer spray at closer range, e.g. when working from the roof ladder 5 (not shown here). The treatment should be started by applying the solution at the level of the ridge 12 and moving the nozzle of spray unit 4 from side to side aiming to penetrate beneath each exposed tile and in each gap between tiles. The solution will be absorbed into the roof structure I initially, but then will begin to run off. At this point the spray should be moved on to the next highest row of tiles of roof surface I to be treated. The run-off will be readily absorbed as it runs down the face of the roof surface 1. Difficult or inaccessible areas 6 should be treated by spraying at close range from the roof ladder 5 or by brush or by other suitable means. In order to work 12/18 at close range the operator 3 should adjust the nozzle of the spray unit 4 to give a fine spray rather than a concentrated jet of liquid. The right hand edge (and all subsequent edge areas) of the roof surface I should be carefully sprayed at close range or brushed to avoid spatter.

When the initial area of treatment 18 has been sprayed a first time it should be left for a period ranging from 15 minutes to 12 hours, but should not ideally be left for a longer period as hardening will occur. The initial area of treatment 18 should then be treated a second, third and subsequent time as before, or until the solution ceases to be absorbed into the structure of the roof I and a glaze begins to form on its surface. At this point the operator 3 may move on to the next area for treatment, i.e. in this case to the left of separation line 17. Alternatively if desired, e.g. when full scaffolding has been provided, the subsequent areas of roof surface I as herein defined by broken lines may be treated after the initial treatment of the roof area 18 and prior to the second treatment of roof area 18. This pattern of work may be repeated until the entire pitch of the roof surface I is saturated with the chemical treatment as described above. When features such as a roof light 16 and surrounding flashing 15 are encountered they should be masked off with suitable materials, e.g. polythene sheeting and adhesive tape, before they come into contact with the sprayed liquid. Ideally, when the initial pitch of the roof surface I has been treated completely the operator 3 should turn his attention to the opposite pitch 8 (as referred to in Figure 1).

Figure 3 shows a typical tile in cross section and the effect of water thereon; where the rain water 20 falls on the exterior surface of the tile 19 but due to ageing 13/18 or other factors the porosity of the material has increased so that the water 20 permeates the tile 19 and forms on the interior surface as droplets 21 which then may migrate into the fabric of the building to cause structural problems. Both in this instance and in Figure 4 the principal illustrated will be seen to refer equally to a variety of materials.

Figure 4 shows a typical tile in cross section and the effect of the treatment thereon. Here the tile 19 has been treated as hereinbefore described so that a first treatment layer 21 has penetrated to the interior surface of the tile 19 and been overlain by subsequent applications of said treatment to form treatment layer 22 and treatment layer 23. The structure of the tile 19 has therefore been impregnated with a water resistant material and therefore when rain water 20 falls onto the exterior surface of the tile 19 it is unable to penetrate the fabric of the tile 19 and therefore will run off under the influence of gravity.

Figure 5 shows the typical overlay pattern of roof tiles and areas requiring particular attention. The tiles 19 are typically arranged in a pattern whereby the roof surface is substantially formed of two layers of tiles 19 in an overlapping and underlapping pattern for additional strength and weather resistance. When treating the roof surface it is important to maximise the penetration of the treatment into the margins of each tile, e.g. at their lower edge 24 and at their lateral edges which define the vertical gap 25 between tiles 19. It is therefore recommended that the sprayed jet of liquid is directed along the line of the lower edge 24 for each row of tiles covered, and at each vertical gap 25 the sprayed jet of liquid is directed upwards to penetrate into said vertical gap 25. This method of treatment will 14/18 increase the penetration of the liquid into the gap between the layers of the roof surface thereby maximising the water repellent effect of the said treatment upon the underlying portions of tiles 19. 15/18

Claims

CLAIMS

Claim 1. A colourless substance or substances and method of application to make impermeable an existing roof wherein said substance or substances is absorbed into the roof structure before hardening of said substance or substances thereby preventing the transmission of moisture to the internal space or fabric of the building.

Claim
2. A substance and method as claimed in Claim I wherein the chemical solution comprises a mixture of a stabilising solution such as epoxy ester resin compound in a Naphtha petroleum base and of white spirit typically a mixture of saturated aliphatic and alicyclic C7-C12 hydrocarbons also known as Turpentine substitute or High Flash White Spirit or Stoddard solvent in the USA.

Claim
3. A substance and method as claimed in Claim I wherein the chemical treatment is water based and comprises a member of the poly vinyl acrylate family of polymers.

Claim
4. A substance and method as claimed in Claim 1, Claim 2 or Claim 3 wherein the treatment is applied by means of a manually pressurised low pressure spray unit.

Claim
5. A substance and method as claimed in Claim I Claim 2 or Claim 3 where the treatment is by means of a high pressure compressor and gravity fed spray gun or by means of a high pressure compressor and pressurised reservoir equipped with manual spraying means. 16/18

Claim
6. A substance and method as claimed in Claims I to 5 wherein the roof structure is formed of tiles made from a fibre-cement mixture.

Claim
7. A substance and method as claimed in Claims I to 5 wherein the roof structure is formed of tiles made from cement.

Claim
8. A substance and method as claimed Claims I to 5 wherein the roof structure is formed of tiles made from clay or ceramic material.

Claim
9. A substance and method as claimed in Claims I to 5 wherein the roof structure is formed of tiles made from slate or slate substitute.

Claim
10. A substance and method as claimed in Claims I to 5 wherein the roof structure is formed of concrete.

Claim
11. A substance and method as claimed in Claims I to 5 wherein the roof structure is formed of fibrous corrugated roofing material (often referred to as asbestos or fibrocement sheet roofing).

Claim
12. A substance and method as claimed in Claims I to 5 wherein the roof structure is formed of wooden shingle or board construction Claim
13. A substance and method as claimed in Claims I to 5 wherein the roof structure is formed from a thatch construction or similar.

Claim
14. A substance and method as claimed in any previous Claim wherein access is provided by means of a ladder, scaffolding, scaffold tower and roof ladder or a combination thereof. 17/18

Claim
15. A chemical treatment and method of application substantially as herein described with reference to Figures 1 to 5 Claim
16. A chemical treatment named RENOV-8 and method of application both substantially as herein described with reference to Figures 1 to 5.