London 020 7060 6593 & Exeter 01392 555 432

About us

After experiencing fundamentally opposing methods of investigating and solving damp and timber defects – from the minimalist approach absorbed while training and working in building conservation, to the product-lead, interventionist approach experienced during a period working for local remedial companies – we formed our company in 2005 to provide an approach based on scientific understating, building conservation and sustainability best practice, all guided by 3 fundamental principles:

Holistic Approach – Promoting informed investigation, minimal intervention and holistic strategies, applying the principles of building conservations for the benefit of all projects.

Ecology –  Not only do we resolve and design out and therefore prevent building defects, we aim to improve our clients health and well-being within their built environment and continually strive to minimise the environmental impact of our activities and look for opportunities to enhance the wider ecology.

Equitable business – To be transparent and fair in all our activities.

“The secret of change is to focus all of your energy, not on fighting the old, but on building the new”


What this means for our clients

Being very good at what we do, combined with our very high professional standards provides our clients with confidence and trust in our judgements and abilities, they appreciate that working together with us will lead to the right solutions being realised, for them, the building and the environment.


What makes us different?

We are highly passionate pragmatic problem solvers, fact finders and creative independent thinkers, using our highly relevant academic knowledge and specialist practical experience, with (potentially irritatingly) high ethical standards, that means we can confidently advise on the best way forward – for all.

We  like to inspire and be inspired by like minded companies and individuals.

We’re a personable lot too, so please do get in touch.


Our History

Lee Harper trained as a conservator, has over 25 years practical experience and has been consulting for over a decade, with relevant academic qualifications including MSc Timber Building Conservation, undertaken at the Weald and Downland Museum, and is currently studying MSc Sustainability and Adaptation (Architecture) at Centre of Alternative Technology (CAT) in Wales, Lee is the driving force at Harper Building Diagnostics. His interests revolve around the environment, his family and trying to play as much sport as his dodgy knees will allow! Read more



Our mission is to help create and recreate healthy homes and environments.

We believe that investigating and solving building defects is just the start, we promote solutions that improve your health and well-being, and ensure that the built environment is not detrimental to the wider environment, minimising our ecological footprint.


Our Philosophy

We have a strong ethical philosophy that is an extension of our personal views and which we believe makes us a better company.

We are transparent in every aspect of our business, with no hidden agendas, only representing the best interests of the client, the building and its users.

We are passionate about conserving both the built and natural environment, which are so entwined in the essence of our daily life.


Our Services

Building conservation and sustainability professionals, specialising in:

  • timber decay
  • damp defects & other material failures
  • repairs – rehabilitating timber
  • environmental drying regimes to control dry rot and wet rot
  • targeted (that’s very targeted) timber preservative treatments
  • material and design appraisal – ensuring defects are not designed into your project when rehabilitating or adapting a building



We are not beholden to any trade body, product manufacturer or have affiliation to any organisation which could compromise our impartiality or philosophy.

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London Office:

Harper Suite 1 Crutchfield Lane, Walton-on-Thames, Surrey. KT12 2QY
Phone: 020 7060 6593

Exeter Office:

The Office, The Old Shippen, Upton, Clyst St Lawrence
Cullompton, Devon. EX15 2NP

Phone: 01392 555 432