GB2116223A

GB2116223A - Resurfacing a roof

Info

Publication number: GB2116223A
Application number: GB08205975A
Authority: GB
Inventors: Roger Louis Bonafont
Original assignee: RUBEROID BUILDING PRODUCTS LIM
Current assignee: RUBEROID BUILDING PRODUCTS LIM
Priority date: 1982-03-01
Filing date: 1982-03-01
Publication date: 1983-09-21

Abstract

An existing surface finish of a roof 1, comprising a plurality of discrete particles 3 projecting from a layer 2 of water-proofing material, is covered by a flowable material 4 such as a bitumenous or cementitious material. The method may also be applied to decks, aprons and similar building components. <IMAGE>

Description

SPECIFICATION A method of preparing a surface Technical field of the invention The invention relates to a method of preparing an existing surface of a substrate such as a roof for subsequent waterproofing treatment, and to a surface so prepared.

Background art Roofs are often surfaced with a layer or dressing of stone bonded in bitumen. Such a layer or dressing is cumbersome to remove before applying a new layer of waterproofing material, often known as built-up roofing. Alternatively the existing layer or dressing is covered over with a rigid board, such as fibre board, which must be mechanically secured to the roof, before a new waterproofing layer is applied. Both methods are time-consuming and expensive.

Disclosure of the invention It is an object of the invention to seek to mitigate these disadvantages of the prior art.

Accordingly, the invention provides a method of preparing an existing surface finish of a substrate which surface finish includes a plurality of discrete particles such as stones or chippings bonded to the substrate, comprising the steps of providing a flowable material which can adhere to the particles and to the substrate and applying that material as a screed over the surface finish so that the discrete particles are covered and a fresh surface provided by the flowable material is formed.

Preferably the method of applying the flowable material is such that a level screed comprising the fresh surface is formed.

Preferably, the method includes the preliminary step of removing any discrete particles which are loose, such removal being by sweeping or any other suitable method.

The flowable material may be bitumen or a cementitious based product.

The bitumen may be filled with inorganic fillers, for example pulverised fuel ash (PFA) or limestone, or modified with polymers.

The bitumen whether alone or filled may be applied as a hot liquid or as a solution or emulsion in a suitable solvent. In the former case, the hot liquid bitumen sets to provide the fresh surface and in the latter case the solvent evaporates to provide a deposited fresh surface layer of bitumen.

The cementitious based products may be Portland Cement inciuding PFA and/or additives to promote a fast cure (set), flexibility and ease of spreading. Suitable additives may be emulsions of polymers such as styrene butadiene rubber (SBR), acrylic co-polymers, or polyvinylidene chloride.

Whichever flowable material is used, the material as it flows over the substrate fills the voids between the discrete particles and covers them to form the fresh surface.

The fresh surface is substantially smooth and provides a firm and hard base to which a further roofing membrane or other waterproofing means may be applied.

The flowable material may preferably be relatively quick and easy to apply for example by being pumped on to the substrate.

Preferably the flowable material may be selflevelling or may be levelled and smoothed using a tool such as a trowel or straight edge.

The material is preferably hardenable in less than 24 hours, preferably much less, to provide a firm hard layer which is the fresh surface.

The set flowable material providing the fresh surface is also preferably of a kind such that in relatively thick sections for example 5-1 Ohmm thick it is tough and flexible enough to withstand without damage both pressure applied during an operation to overlay it with roofing felt and the movement of non-rigid decks such as metal decks.

The fresh surface preferably does not have loose powders, flakes or laitance on the exposed surface.

It will be understood that the term "substrate" used herein is intended to cover roofs, decks, aprons and similar building components.

It will also be understood that the invention extends to a roof, deck, apron and the like which has a fresh surface applied to it by a method as hereinbefore defined, whether that surface is a final surface or is an intermediate surface in the finished roof, deck, apron or the like.

A roof preparing by a method embodying the invention is hereinafter described, by way of example, with reference to the accompanying drawing, which shows a cross-section through part of the root Referring to the drawing there is shown a roof 1 which has an existing surface finish comprising a layer 2 of waterproofing material to which is bonded a plurality of discrete particles such as stones or chippings 3 which are bonded to the roof 1 by the layer 2 and which project from or stand proud of that layer 2.The existing surface finish 2, 3 is prepared for application of a further waterproofing membrane (not shown) by flowing over the existing surface a screed of a flowable material such as a bituminous material which forms a fresh surface layer 4 and which flows into the voids between the stones or chippings 3 and covers them so that they do not protrude through the fresh surface layer 4 formed. When the fresh surface layer 4 has hardened, it provides a smooth, firm surface to which the further waterproofing membrane (not shown) may be adhered.

Claims

1. A method of preparing an existing surface finish of a substrate which surface finish includes a plurality of discrete particles such as stones or chipping bonded to the substrate, comprising the steps of providing a flowable material which can adhere to the particles and to the substrate and

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION A method of preparing a surface Technical field of the invention The invention relates to a method of preparing an existing surface of a substrate such as a roof for subsequent waterproofing treatment, and to a surface so prepared. Background art Roofs are often surfaced with a layer or dressing of stone bonded in bitumen. Such a layer or dressing is cumbersome to remove before applying a new layer of waterproofing material, often known as built-up roofing. Alternatively the existing layer or dressing is covered over with a rigid board, such as fibre board, which must be mechanically secured to the roof, before a new waterproofing layer is applied. Both methods are time-consuming and expensive. Disclosure of the invention It is an object of the invention to seek to mitigate these disadvantages of the prior art. Accordingly, the invention provides a method of preparing an existing surface finish of a substrate which surface finish includes a plurality of discrete particles such as stones or chippings bonded to the substrate, comprising the steps of providing a flowable material which can adhere to the particles and to the substrate and applying that material as a screed over the surface finish so that the discrete particles are covered and a fresh surface provided by the flowable material is formed. Preferably the method of applying the flowable material is such that a level screed comprising the fresh surface is formed. Preferably, the method includes the preliminary step of removing any discrete particles which are loose, such removal being by sweeping or any other suitable method. The flowable material may be bitumen or a cementitious based product. The bitumen may be filled with inorganic fillers, for example pulverised fuel ash (PFA) or limestone, or modified with polymers. The bitumen whether alone or filled may be applied as a hot liquid or as a solution or emulsion in a suitable solvent. In the former case, the hot liquid bitumen sets to provide the fresh surface and in the latter case the solvent evaporates to provide a deposited fresh surface layer of bitumen. The cementitious based products may be Portland Cement inciuding PFA and/or additives to promote a fast cure (set), flexibility and ease of spreading. Suitable additives may be emulsions of polymers such as styrene butadiene rubber (SBR), acrylic co-polymers, or polyvinylidene chloride. Whichever flowable material is used, the material as it flows over the substrate fills the voids between the discrete particles and covers them to form the fresh surface. The fresh surface is substantially smooth and provides a firm and hard base to which a further roofing membrane or other waterproofing means may be applied. The flowable material may preferably be relatively quick and easy to apply for example by being pumped on to the substrate. Preferably the flowable material may be selflevelling or may be levelled and smoothed using a tool such as a trowel or straight edge. The material is preferably hardenable in less than 24 hours, preferably much less, to provide a firm hard layer which is the fresh surface. The set flowable material providing the fresh surface is also preferably of a kind such that in relatively thick sections for example 5-1 Ohmm thick it is tough and flexible enough to withstand without damage both pressure applied during an operation to overlay it with roofing felt and the movement of non-rigid decks such as metal decks. The fresh surface preferably does not have loose powders, flakes or laitance on the exposed surface. It will be understood that the term "substrate" used herein is intended to cover roofs, decks, aprons and similar building components. It will also be understood that the invention extends to a roof, deck, apron and the like which has a fresh surface applied to it by a method as hereinbefore defined, whether that surface is a final surface or is an intermediate surface in the finished roof, deck, apron or the like. A roof preparing by a method embodying the invention is hereinafter described, by way of example, with reference to the accompanying drawing, which shows a cross-section through part of the root Referring to the drawing there is shown a roof 1 which has an existing surface finish comprising a layer 2 of waterproofing material to which is bonded a plurality of discrete particles such as stones or chippings 3 which are bonded to the roof 1 by the layer 2 and which project from or stand proud of that layer 2.The existing surface finish 2, 3 is prepared for application of a further waterproofing membrane (not shown) by flowing over the existing surface a screed of a flowable material such as a bituminous material which forms a fresh surface layer 4 and which flows into the voids between the stones or chippings 3 and covers them so that they do not protrude through the fresh surface layer 4 formed. When the fresh surface layer 4 has hardened, it provides a smooth, firm surface to which the further waterproofing membrane (not shown) may be adhered. Claims

1. A method of preparing an existing surface finish of a substrate which surface finish includes a plurality of discrete particles such as stones or chipping bonded to the substrate, comprising the steps of providing a flowable material which can adhere to the particles and to the substrate and applying that material as a screed over the surface finish so that the discrete particles are covered and a fresh surface provided by the flowable material is formed.

2. A method according to Claim 1, including the preliminary step of removing any discrete particles which are loose.

3. A method according to Claim 1 or Claim 2, the flowable material being bitumen or a cementitious based product.

4. A method according to Claim 3, in which where the flowable material is bitumen, said bitumen is filled with inorganic filler(s).

5. A method according to Claim 3 or Claim 4, in which where the flowable material is bitumen, the said bitumen is applied as a hot liquid or as a solution or emulsion in a suitable solvent.

6. A method according to Claim 3, in which where the flowable material is a cementitious based product, that product is Portland Cement.

7. A method of preparing an existing surface finish of a substrate which surface finish includes a plurality of discrete particles such as stones or chippings bonded to the substrate, substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

8. A substrate with a surface finish whenever prepared by a method according to any preceding Claim.