Our property expert answers all your questions

When we’re renovating our homes, or buying and selling them, we all have questions.

Scottish Field has, on hand, Ewan M. White, who provides impartial, expert advice on a wide range of building and preservation issues.

Ewan’s role is to ensure there is a thorough scientific justification for any works to be carried out, and that unnecessary works are not undertaken. This gives clients peace of mind, and protects their interests throughout the building and preservation process.

Ewan is a registered scientist, expert witness and independent consultant with over 35 years’ experience in the building and preservation industry.

Providing a range of specialist services including diagnostic site inspections and surveys, Ewan reports on all aspects of dampness, condensation, timber decay and building defects.

Ewan has extensive experience of working with a vast array of residential and commercial buildings throughout the country, from Grade A listed properties to complex new builds.

Through his specialist building defects consultancy, Ewan aims to protect his clients’ interests by ensuring that the extent of proposed works are warranted, and that the recommended course of action is the most appropriate and cost-effective solution.

Q. I have recently received a quotation for several thousand pounds to basically strip all the tiles from my roof and completely renew. The roofer says that the existing tiles are porous and beyond repair due to recently having them cleaned. Can cleaning cause such damage?

A. Thanks for the query and after looking at all the photographs, it would appear that the information in your quotation is correct.

The National Federation of Roofing Contractors ( NFRC ) issued a statement in 2012 on this very subject: Most ‘techniques’ that we have come across to remove moss, are often achieved by ‘violent’ means such as power washing, which may cause damage to the roof, especially when combined with unnecessary foot traffic often leading to cracked and broken roof tiles.

Regarding the ‘foot traffic’ this is normally caused when the power washing is carried out. In the attached photograph, it would seem that an attempt to repair such a break has been carried out with a sealant.

In summary, there would seem to never a good reason to power wash roof tiles and as such the longer things are left alone the better.

Q. I live in a house that was built new in 2018 and since moving in I note that there is staining to the base of the wall and also dark spots appear from time to time on sections. The developer has removed the spots on two occasions but they eventually reappear. I am worried that there is a serious underlying issue that requires to be resolved.

A. From your photo, it appears that your house is affected by an issue that I hear is becoming ever more common.

Some storms of late have been such that the existing gutters have been unable to contain the level of rainwater (particularly on a large roof area such as your house) What can happen is that the rainwater hits the gutter, then as most gutters are rarely spotless, whatever is present goes up and over then hits the wall in patches.

This is not the fault of the developer as the gutters appear to have been fitted as per regulations. There is unfortunately no easy remedy here and hopefully for the majority of the year this will not be an issue. If however heavy storms are here to stay, there will need to be a collective thought on rainwater goods.

If you have a question for Ewan, send it to with ‘Ask the expert’ in the subject matter.

For more information about Ewan’s work, visit