The practice of issuing long term guarantees emerged around the turn of the twentieth century when roofing with bituminous membranes first made its impact upon the construction industry. At the time the industry relied mainly upon pitched roofs, and the demand for flat roofing was comparatively low.
The primitive method was simply to saturate a layer of hessian in coal tar and then blind it with sand. This means of waterproofing called for extensive remedial treatment more or less annually if it was to be effective, so a new method evolved whereby a multilayer system of hessian was puddled at one and the same time to give more lasting protection.
Then, a change in architectural thinking caused a sudden and dramatic upsurge in the demand for flat roofs, and existing methods of waterproofing such as described above was considered far from satisfactory. This provided great impetus for the development of saturated felts and self finished roofing in which the bitumen content is factory controlled, but these new materials created the need for new skills to apply them. Manufacturers quickly found that they were not only required to supply their “new fangled” products but also to undertake contracts for their effective application.
As a whole, the construction industry approached these new methods and materials with extreme caution and, in order that they should be accepted, it was necessary for manufacturers to provide an inducement in the form of guarantees, linking a built-up roofing specification to a life of 10, 15 or even 20 years.
During the years that followed, countless organizations both large and small engaged themselves in the field of built-up roofing. Frequently the smaller contractors issued the most lavish guarantees, but they were not worth the paper they were written on, for by the time the claim was made, the contractor had gone out of business and vanished. Fortunately there also emerged a smaller number of bona fide roofing contractors who were masters of their craft and upon whom the architects and other specifiers knew they could rely.
Once long-term guarantees had served their purpose when the materials were untried and unproven, operation on such a basis eventually became outmoded and unnecessary. Conditions in forms of contract and other similar documents now lay down specific requirements as to the periods and conditions relating to the defects and liability of the specialist-roofing contractor.

Manufacturers Guarantees

In the United States many roofing contracts are carried out by independent “approved applicators” whose only bond with the manufacturer is the latter’s approval. Consequently, manufacturers have to guard extremely carefully against underwriting responsibilities over which they have no direct control. This means extremely complex forms of guarantee, which need to be carefully scrutinized by each party concerned to know precisely where he stands. If a long term guarantee is required by the customer, this must be stated at the time of tendering to the approved applicator so that it may be taken into account in the price, the guarantee itself being issued by the manufacturer and “hedged” with a reputable insurance company specializing in this type of business and imposing further conditions. Obviously this procedure adds to both the cost and complexity of the contract. Insurance companies such as Underwriters Laboratories and Factory Mutual who specialize in this type of cover actually have their own recommended specifications and requirements for roofing membranes, insulation boards, fixings, etc. to which their clients (the manufacturers) must comply, for coverage.
When all the “small print” in a guarantee is cast aside, the only real guarantee for any roof lies in the reputation of the contracting company, who supplies and fixes it, carrying out a first class and reliable job in the field in which it specializes in.

The above article was taken from `Ruberoid Round the World” January 1971, written by Mr. R.D Clarke, Ruberoid Export Manager. Nothing much has changed in over 30 years, many manufacturers and contractors have come and gone, some by retirement, some by attrition, some have been bought out and some have changed their names over the years. New products still offer outlandish Guarantees to induce acceptance in the construction industry and many “tradesmen” still jump trades to capitalize on a new product which is the latest fad with architects, without proper training and experience in the field.

As the lawyers say “Caveat Empor” (Buyer Beware), if the offer of a new, cheap, seamless, can be applied in the rain, guaranteed 30 years, type waterproofing system sounds too good to be true, it probably is.

New Zealand Guarantees

In New Zealand it is not possible to obtain insurance cover for failure of roofing projects, there are no specialist construction insurers operating in NZ and the risk is known in the general insurance field as “contractors risk”.
Generally a 5 Year workmanship warranty will provide enough cover to establish that the workmanship has been completed satisfactorily, as most defects show up within the first 6 months.
Some contractors are able to offer comprehensive Guarantees linked to the membrane supplier / manufacturer, in this situation the supplier will inspect the work of the contractor on completion and approve the workmanship, and the liability is shared. If the contractor should go out of business during the period of the Guarantee the client is still covered by the supplier and generally they will provide another contractor to fix any defects.
In the end it is the clients responsibility to research the products and vet the people who undertake their roofing work, a handyman builder or a well meaning neighbor may give helpful advise, but in the end it seems common sense to contract with a professional roofing company who specialize in the particular field of roofing required, rather than to use a company or individual who “do a bit of roofing on the side”.

Scie Construction Ltd Guarantees

Scie Construction offer quite extensive Guarantees for materials, based on their actual performance in NZ over a period of time and from research on case histories in other countries around the world with similar climatic conditions, our Guarantees for workmanship are based on actual experience using the products and evaluating their performance in NZ conditions.
For example, the Ruberoid Britorch Blue / Grey Slate surfaced Torchon membrane we have specified and used, has been laid in NZ since 1987 without a single failure due to breakdown of material, and our inspections back on early projects show the membrane will have a life expectancy in excess of 20 years. Ruberoid’s UK research laboratory confirms this and  Scie can confidently offer 15-20 Year combined material and workmanship guarantees in New Zealand.
The NZ Building Code requires that roofing materials have a minimum life expectancy of 15 Years.
We think that Decks over habitable areas, are roofs and the same requirement should apply, although this is not required under the current code..

Examples of Our Guarantees

New mastic Asphalt Tanking or Roofing – 20 Years
New and ReRoof Projects Sarnafil PVC – 20 Years
New and ReRoof Projects Nuratech TPE – 20 Years
New Project Torchon Mineral Roofing 1 layer SBS – not available
New Project Torchon Mineral Roofing 1 layer APP – not available
New Project Torchon Mineral Roofing SBS 2 layers – 15-20 Years
New ProjectTorchon Mineral Roofing APP 2 layers – 15-20 Years
ReRoofed Torchon Mineral Roofing 1 layer SBS – 10 Years
ReRoofed Torchon Mineral Roofing 1 layer APP – 10 Years
ReRoofed Torchon Mineral Roofing SBS 2 layers -15- 20 Years
ReRoofed Torchon Mineral Roofing APP 2 layers – 15-20 Years
New Project PVC Deck Membrane – 15 Years
ReRoofed Deck PVC Membrane with new Plywood substrate – 15 Years
Roof Overlay Torchon Mineral over BuiltUp Bitumen Roofing – 5-10 Years
Roof Overlay Torchon Mineral over Acrylic/Fibreglass Roofing – 10 Years
New Project Ardex Butynol 1mm Black – 20 Years
New Project Ardex Butynol 1.5mm Black – 20 Years
New Project Ardex Butynol 1.5mm Dove Grey – 20 Years
New Project Ardex Butynol 1.2mm Dove Grey – 15 Years
ReRoof Ardex Butynol 1mm and 1.5mm Black or Dove Grey – 20 Years (with new plywood substrate)
ReRoof Ardex Butynol 1.5mm Black or Dove Grey – 10 Years (re-screwed and repaired existing substrate)
It is not recommended to use 1mm Black or 1.2mm Dove Grey on existing old substrates unless approved by an Ardex Representative.

Workmanship Guarantees for other types of waterproofing work vary according to the project, ie Tanking, Asphalt Shingles, Roof Repairs, but generally we will stand by any of our work for a minimum 10 Years.


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