Delta: Professional Indemnity Insurance in Structural Waterproofing

  • 31 May 2024

Professional Indemnity Insurance (PI) is a type of insurance that covers a business or an individual who provide(s) advice or professional services that a third party is reasonably entitled to rely upon. In the event that the third party suffers a financial loss because of a failure by that business or individual to exercise reasonable skill and care, the third party has the potential to make a claim on Professional Indemnity Insurance (PI). If the third party makes a claim of valid professional negligence, the legal costs (and, compensation) may be paid, wholly or in part by the insurer. Delta Membranes has more…

With Design and Build emerging as one of the most common contractual arrangements in UK construction, Professional Indemnity (PI) insurance should be a necessity.  

The UK construction industry widely acknowledges that structural waterproofing is undertaken by ‘specialist contractors’ and the design elements of this sit firmly on the specialist contractor’s shoulders. 

Whilst many specialist contractors will have insurance, not all will carry suitable PI Insurance that covers the scope of work undertaken.

PI Insurance for Structural Waterproofing Professional

PI insurance works in a different way to most other construction insurances, so presents a different risk profile for insurers. A key difference is that PI insurance policies are underwritten on a ‘claims made’ basis, whereas most other liability policies are underwritten on an ‘occurrence’ basis.

With PI insurance becoming increasingly difficult for structural waterproofing professionals to obtain for waterproofing designs/waterproofing Design and Build, Delta Membrane Systems Limited is delighted to have partnered with PHL Insurance, a specialist broking services provider with experience in the construction sector, who can access Professional Indemnity Insurance for you. 

Defect errors in the waterproofing of a building can be immediately recognised, whilst some can go undiscovered (even after a building has been completed and is in use). 

It is also not uncommon for the consequences of a waterproofing defect to incur costs and losses far in excess of the value of the design work that led to them. 

The Building Safety Act, which has extended the Defective Premises Act to include refurbishment and other works in addition to new dwellings, has increased the time period for compensation claims for retrospective work from 6 years to 30 years. For new work, the liability period has been extended to 15 years.

To be eligible 

All Delta Registered Installers are eligible to apply for PI Insurance with PHL Insurance.  

Delta Registered Installers/Specialist contractors who are only undertaking design work should ensure their PI insurance contains design liability obligations. If the design input is very limited or specific, this should be clearly stated in the contract.  


As an independent specialist contractor, PHL Insurance recognise every specialist contractor is different and will have different insurance requirements, their recommendations will be tailored to suit your business needs, ensuring you have the right cover for your projects, whether it’s designing a waterproofing solution for a podium deck or Design and Build for a new basement.  

Whether you are taking out a new PI policy or renewing an existing one, just complete a downloadable Proposal Form and Supplemental Questionnaire. Take care to ensure all forms are completed to the best of your ability – take time to dot the i’s and cross the t’s.

Delta Membrane Systems,
Delta House,
Merlin Way,
North Weald,
CM16 6HR
United Kingdom

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