About Us

Founded by CEO Robin Plaster in 2017, we have more than 35 years’ combined experience in the new-build structural defects sector.

Having previously been instrumental in establishing what is the second largest warranty provider in the UK, Robin and his team bring a wealth of experience and passion to the building warranty market. One Guarantee is able to provide cover on a range of properties from single new-build units up to £50 million mixed-use developments.

With our AA-rated (Standard & Poor’s) global insurer, you can be confident that our warranties will give you the peace of mind your property deserves. Our extensive surveying network means that we are able to offer warranties throughout the UK.

Who we are

Our experienced team, based in London and Norwich, provides an efficient yet personal service to all our clients.

Your dedicated account manager will see each project through from the quotation stage to practical completion and we often look to meet with you on-site throughout the construction phase.

Not only does One Guarantee offer comprehensive cover under our structural warranty policies – which are accepted by the majority of UK mortgage lenders – we also provide access to building control via our Approved Inspector network.

And we don’t just work with developers and housebuilders. One Guarantee also partners with brokers and introducers, offering a flexible approach to best serve your client’s needs. For more information, please visit our dedicated page.

One Guarantee is a Registered Code User and supporter of the Consumer Code for New Homes (CCNH). This ensures support and protection is provided to consumers purchasing new-build homes throughout the UK. The CCNH is a Chartered Trading Standards Institute Tier Two approved scheme.

How we work

Over the years, we’ve focused on making the process of arranging a building warranty as straightforward as possible. We understand the importance of a smooth and hassle-free service, particularly when it comes to the issuing of certificates at completion.

Our national network of surveyors will work with you throughout the key stages of the build, with regular on-site technical support to ensure the highest standards of construction are maintained and delays avoided.

Our Values

Professionalism
Our experienced and trustworthy team strives to provide a professional, solutions-based approach to our clients at all times. We treat our clients with respect and believe in forming long-term relationships with all of our clients.

Flexibility
One Guarantee knows every project is unique. That’s why we don’t take a ‘one size fits all’ approach. Our team will work with you to meet your specific requirements.

Dedication
At One Guarantee, we’re passionate about what we do. That’s why we’re always happy to go the extra mile to help our clients obtain a structural warranty. This includes progress reviews and site meetings.

Integrity
Our honest and consistent approach to providing warranties helps clients to understand our offering. Our ethics and morals give us a long-term approach to client relationships.

Skilled
Our knowledgeable team is highly skilled in all aspects of meeting our clients’ warranty requirements. We provide useful advice along with our products to add value to the process.

Accord Buy to Let

Accord Mortgages

Ahli United Bank (UK) plc - consider on an individual case by case basis

Aldermore Bank PLC

Atom Bank PLC

Aviva Equity Release UK Ltd

Bank of Scotland Beginning A

Bank of Scotland Beginning O

Banks and Clients Plc – consider on an individual case by case basis

Barclays Bank UK PLC

Barnsley Building Society

Bath Building Society - consider on an individual case by case basis

Beverly Building Society

Birmingham Midshires

Bishopsgate Funding

Bluestone Mortgages

Britannia Building Society

Buckinghamshire Building Society Loans – consider on an individual case by case basis

Charter Mortgages

Charter Savings Bank

Chelsea Building Society

Cheltenham & Gloucester

Cheshire Building Society

CHL Mortgages

Chorley and District – may consider on an individual case by case basis

Co-Operative Bank

Coutts

Coventry Building Society

Cumberland Building Society – consider on an individual case by case basis

Cynergy Bank

Darlington Building Society

Derbyshire Building Society

Dudley Building Society – consider on an individual case by case basis

Dunfermline Building Society

Ecology Building Society – consider on an individual case by case basis

E-MEX Home Funding Limited

Family Building Soc (a trading name of National Counties BS) – consider on an individual case by case basis

First Direct Bank

Fleet Mortgages

Foundation Homeloans

Generation Home

Godiva Mortgages

Goldentree Financial Services Plc

Guernsey Home Loans

Halifax

Halifax Loans Ltd

Hampden and Co

Hampshire Trust Bank

Handelsbanken – consider on an individual case by case basis

Harpenden Building Society

Heritable Development Finance

Hinckley and Rugby Building Society

Hodge

Hodge Equity Release

HSBC UK Bank plc

InterBay

Intelligent Finance

ITL Mortgages

Jersey Home Loans

Kensington Mortgage Company Ltd

Kent Reliance

Keystone Property Finance

Landbay – consider on an individual case by case basis

Leeds Building Society

Leek United Building Society

Legal & General Home Finance Ltd

LendInvest

LiveMore Capital

Lloyds Bank plc pre fixed 20/40

Lloyds Bank plc pre fixed 50/30/77

Lloyds TSB Scotland plc

Market Harborough Building Society – consider on an individual case by case basis

Masthaven Bank – consider on an individual case by case basis

MBS Lending Ltd

Melton Mowbray Building Society

Molo Finance

Monmouthshire Building Society

Monument Bank

Mortgage Agency Services

Mortgage Trust

MPowered Mortgages

MSP Capital Ltd

National Counties Building Society – consider on an individual case by case basis

Nationwide Building Society

Newbury Building Society – consider on an individual case by case basis

Norwich & Peterborough Building Society

OSB India

Paragon Buy to Let Mortgages

Paragon Residential Owner-Occupied Mortgages

Paratus AMC Ltd

Parity Trust – consider on an individual case by case basis

Pepper Money – consider on an individual case by case basis

Platform (a trading name of The Co-operative Bank p.l.c.)

Portman Finance Ltd

Precise Mortgages

Prestige Finance

Principality Building Society

Regentsmead – consider on an individual case by case basis

Saffron Building Society

Santander UK plc

Scottish Building Society – consider on an individual case by case basis

Scottish Widows Bank

Secure Trust Bank PLC

Shawbrook Bank

Skipton

Smile (a trading name of The Co-operative Bank p.l.c.)

St James Place Bank

Swansea Building Society

Tesco Bank (a trading name of Tesco Personal Finance plc)

The Cambridge Building Society – consider on an individual case by case basis

The Holmesdale Building Society

The Loughborough Building Society

The Mortgage Business

The Mortgage Lender Ltd

The Mortgage Works

The Royal Bank of Scotland plc

The Royal Bank of Scotland plc Direct Line Mortgages

The Royal Bank of Scotland plc Direct Line One

The Royal Bank of Scotland plc First Active

The Royal Bank of Scotland plc Natwest one Account

The Royal Bank of Scotland plc One Account

The Royal Bank of Scotland plc Virgin One

TSB Bank plc

UCB Home Loans Corporation Limited

Ulster Bank

Vernon Building Society – will consider on case by case basis

West Bromwich Building Society

Whistletree (a trading name of TSB Bank plc)

Yorkshire Building Society

Zephyr Mortgages (Topaz)