London 020 7060 6593 & Exeter 01392 555 432


Below are a selection of endorsements to illustrate the range of services we provide and what our clients think about us.

Grade II Listed, granite cottage, Cornwall

We further investigated potential damp and timber problems which had been raised in a pre-purchase survey.

We employed Lee Harper to carry out a damp and timber survey on a 300 year old Grade 2 listed property that we were buying in Cornwall.
We were delighted with the detailed report that we received which included a breakdown of the work required and possible costs involved. This allowed us to make an informed decision on the property.
Lee kept us up to date throughout the process and we found him to be very helpful and knowledgable. We would have no hesitation in recommending Lee and would certainly use his services again if necessary.

Mr and Mrs Rondelli, Cornwall

Converted agricultural barn, Devon

After studying the pattern and distribution of dampness, further targeted investigations were able to establish that leaking pipes were responsible for the recent appearance of damp.

Lee has been a fantastic support from the moment he arrived to conduct a survey of our home.  We had a very new, and very strange damp issue.  During his visit he was able to determine the source of our damp problem, and explain all the weird phenomena we had noticed within our living room and kitchen diner – salt deposits vs fungus, which fungal growth we should monitor, which fungal growths we could ignore.  Lee advised us brilliantly on how to proceed with our insurance company, and what we could do in the short term to minimise further problems, while the insurers got underway with their assessment and planning.  He provided us with his full and detailed report in just a couple of days, so we had it ready for our insurance company on their first visit to our home.
At every stage Lee has offered us his expert knowledge and thoughtful consideration of issues as they have arisen.  It’s been a massive support for us to have him on board as we face the necessary repair work and our insurance company.

Mr & Mrs H, Devon


Grade II Listed, Victorian private residence – recurrent dry rot outbreak

Investigating a reoccurrence of a dry rot outbreak, identifying the causation which was previously misdiagnosed, providing recommendations to minimise the risk of further damage, and instructions to monitor the repairs.

Five years ago we had an outbreak of dry rot in the cellar beneath the dining room in our Victorian home. This was ‘fixed’ at great expense, mainly due to complete replacement of half the flooring timbers and a lot of plasterwork, plus chemical spraying to the cellar walls and all areas affected, by a specialist subcontractor. The rot recently returned – in the same place and with renewed vigour – and we discovered that the ’20 Year Guarantee’ given by the chemical treatment company was not what we thought it be in terms of re-work and compensation (nil), due to careful drafting.  Research on the internet revealed that disputes over such guarantees is not uncommon, i.e. where companies offer chemical treatment of dry rot (and clients taking this to mean ‘eradicate’, unsurprisingly!), and giving guarantees they know could be problematic in terms of what clients believe them to be. Our research also revealed to us the complexity, resilience and alarming tenacity of dry rot and how extremely difficult it is to eradicate it since the various conditions for its appearance, growth and reproduction are many, and chemical treatment alone is totally ineffective unless these other conditions are thoroughly addressed.
We felt bereft of unbiased, comprehensive advice. Our builders are excellent but we now know this to be a highly specialised and complex problem needing corresponding levels of expertise. The chemical treatment company were uninterested in offering any detailed help or advice, merely offering to re-spray the affected areas, which again, can only be a single component of any planned eradication.
So we decided to appoint Lee Harper to carry out a full examination of the areas. The service they provided was excellent both in terms of the comprehensive analysis carried out and the resulting recommendations which focused on changing the environment in the area concerned in terms of dampness, air circulation, etc. in order to render it hostile to the life cycle of the dry rot organism. We believe we are now on the way to seeing the problem finally resolved. Lee Harper’s knowledge, service and support is excellent and we wouldn’t hesitate to recommend him.

John, Leamington Spa

Grade II Listed, 17th Century timber-framed private residence

Investigated damp issues, assessed adjacent timbers, provided report including holistic recommendations.

Now on my second period house that Harper Building Diagnostics have advised me on and I can’t recommend Lee highly enough. Friendly, knowledgeable and practical advice, that I have no hesitation in acting upon. They won’t drag it out and make a meal of it so they can charge you more, they’re just straightforward and helpful.  You can’t ask for more.

Mr Johnson, Hertfordshire

The site includes a 19th Century Mill with earlier origins, and a row of workers cottages.

During our initial consultation, we assessed damp issues and discussed the clients plans for the cottages, and the wider site complex.
We were kindly invited back to the Mill to demonstrate the nuances of installing a limecrete breathable floor. It was rewarding to see what an excellent job the Mill team had done of subsequent floors.

Lee assessed the damp issues at the cottages adjoining the main Mill house. They sit below the water line and were beset with mould and all manner of damp.
With Lee we discussed the practicalities and options of re-converting the rented cottages, badly converted from agricultural buildings in the seventies. We wanted to use a method that followed our sustainable vision.
Though we had already explored several options and had other consultations we decided that Lees approach made the most sense to us , both practically and ecologically. We later hired Lee and his team to demonstrate the installation of a limecrete floor with a view that our team could then install subsequent floors. The process went well and we have decided to implement his further recommendations. Lee is extremely approachable, down to earth, optimistic and importantly, we all got a strong feeling that he was ‘on our side’ . We would certainly hire him again a little further down the line when we need expert advice and an encouraging presence.

Sarah, Mark & Ben, Devon

A Victorian terraced property, ground floor flat, London – recurrent dry rot outbreak

Investigated a dry rot outbreak following previous unsuccessful attempts at controlling the fungus.
Assessing the extent and severity of the damage using non-destructive techniques, and identifying possible causation.
Our report included recommendations for contractors to follow.

The difference between the service offered by Harper Building Diagnostics and other dry rot investigation companies is immense. Prior to contacting Lee, I had an inferior company survey my property for dry rot and was dissatisfied with the level of service. By contrast, Harper Building Diagnostics could not have been more reassuring and helpful. It was clear that they were experts in their field. Lee brought a van-load of professional equipment and was so thorough and precise. He gave me so much useful information on the day and followed it with a detailed survey report and thorough remedial instructions. Invaluable!

Victoria, London E10

Converted agricultural barn, approx. 1920’s brick construction – damp survey

Investigations discovered that the property had cavity insulation installed at the time of conversion, which was wet, facilitating the transfer of moisture towards the inside of the property. I
The contractor refused to take responsibility and remove the insulation, so our report was used as evidence to present to CIGA (installers trade body), who concluded that it was an inappropriate installation and the insulation should be removed free of charge.

After buying a partially converted barn, I finished the conversion and moved in with my partner and two young children.
After a few months of living in the property we soon realised we had a major damp problem to the extent where you could physically see the water running down the wall.
I have many years of building experience and could not solve the problem. Prior to Lee’s visit I had a ‘damp specialist company’ complete a survey and their outcome was the wall tanking was reacting with salts.
With no solution in sight, I contacted Lee. From the beginning Lee was understanding of my situation and the severity of the damp. Lee was very prompt and even completed the survey on a Saturday.
Lee carried out a full survey focusing on the damp areas. I found Lee to be very knowledgeable with his work. He explained everything and gave me the knowledge to solve the problems using conventional methods but age sympathetic to the barn.
One thing that stuck out to me about Lee and made him different from any company I have dealt with – Lees approach to his work is to find the problem and resolve it using correct building methods, not use a product that only has so many years guarantee.
I am now confident that the problem has been resolved not just masked over.
I would highly recommend Lee and will defiantly use him for further surveys

L Cooper, The Granary, Devon

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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