To assist the specifier in deciding on the correct waterproofing specification, the Newton Waterproofing Index (or 'NWI') is a unique waterproofing specification tool which has been developed as a means of assessing the ability of a waterproofing specification to successfully protect an earth-retaining or below-ground structure. This assessment is based both upon the type of structure involved, and the type/s of waterproofing being used.  

The purpose of the Newton Waterproofing Index is to give specifiers an accurate understanding of the potential success of different specifications and builds, as well as helping to guide them through the myriad of different waterproofing products and combinations available in the market. Visually, this assessment is then represented as a NWI 'score' that can be used to judge each waterproofing specification.

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The Scoring System

The scoring system works in conjunction with the British Standard for waterproofing, which defines the three types of desired internal environment as Grades 1, 2 and 3. By reflecting these Grades in the scores, the Index makes it quick and easy to visually assess a design, from 0 through to 4.0.

Once assessed by Newton, designs are appointed with a scoring range, due to the fact that even within an agreed specification, the effectiveness of the waterproofing depends on the competency of the installation. For ease, these scoring ranges will also be presented on a scale.

The lower score indicates the standard that can be achieved even with imperfect workmanship, indicating a safer specification that will result in a good level of waterproofing, even if the installation and build are not of the highest standard. 

The upper score can be achieved by those that are trained in the installation. The larger the range, the higher the risk that an imperfect installation will affect the waterproofing.

The Scoring Scale

Tailored Specification Sheets

Newton Specification Sheets are an integral tool within the Index, each bringing together key product information, NBS Clauses and 3D drawings into one complete resource. Each Newton Specification Sheet also carries an Index score that is defined by the specification and the structure to which it is applied.

"We’re delighted to introduce the Newton Basement Shield and Waterproofing Index to the UK waterproofing industry. Newton and our Specialist Basement Contractors can now provide specifiers, developers and contractors with a guaranteed specification that provides A-rated cover on the design, products and installation. For the UK waterproofing market this is a ground breaking innovation and it highlights Newton’s ongoing campaign to improve standards throughout the industry"

Warren Muschialli, Managing Director, Newton Waterproofing Systems

The Newton Basement Shield

The Newton Basement Shield is a comprehensive guarantee available on a wide choice of solutions, provided they are installed by a Newton Specialist Contractor. The most comprehensive specifications that achieve the top Newton Waterproofing Index score also qualify for a reduced cost. 

The Newton Basement Shield will guarantee the project with a bespoke latent defects policy, including:

10 years LDI cover with an A rated Lloyds insurer
2 years defects liability period
Up to £10,000 of cover per project
Cover for product, design and installation failures
In-house design assistance and on-site quality assurance
Independent auditing included where required, to ensure continued quality

*For full information on the Newton Basement Shield guarantee please contact our Technical Team on 01732 806998 or via