Tim Hollingsworth
“Tim Hollingsworth, managing director of leading estate agency and surveying firm Rumball Sedgwick, knows all about Japanese Knotweed, and how it sends a tingle up the spine when you mention it to a purchaser of a property. But should it?

I was contacted recently by a neighbour who is trying to sell his house, which is a good sized family home in a desirable part of central Watford. In my opinion, it is reasonably priced, and he should not have any trouble selling it. However, it has not sold, and he wanted my view on why that might be, and what he could do about it.

He went on to tell me that the previous summer, his gardener had found a small clump of Japanese Knotweed at the bottom of his garden. Although he had had it professionally treated, he was concerned that the selling agent was flagging it up to potential buyers, and this was putting them off.

Although this nuisance plant is very rare locally, isolated appearances can happen due to bird droppings or similar. However, as far as houses are concerned, this really falls into the category of easily resolvable problems, and in my view, is not something that buyers should be unduly worried about.

Despite this plant having a reputation of being able to break up bricks and concrete, in all my (many!) years of surveying, and over the thousands of buildings I have seen, I have never come across an instance where it has actually done so. And like most problems affecting buildings, effective solutions usually become available within a few years of the problem being identified.

So, in the case of Japanese Knotweed, there are now very well established and effective treatment regimes which will get rid of it permanently. RICS (the Royal Institution of Chartered Surveyors) has produced guidance on the matter, and suggests that as long as it is not too close to the property and a suitable programme is in place to eradicate the plant then there is no real issue.

In the UK, we have strict Building Regulations, which mean that most houses are very robust, and will continue to do their job effectively for many decades or even centuries. Sometimes an issue will come along which means some adjustments may be required – for example, in the late 1970s, there was a significant problem of subsidence, due to a series of long hot dry summers which caused an imbalance in water levels in the ground.

At that time, Rumball Sedgwick advised on many insurance claims for subsi-dence. However, properties were rarely so badly affected that they could not be restored. Within a few years, most affected properties had been underpinned, and then brought back to the market. Now, 30 plus years on, those properties are just as good, and just as saleable, as the ones next door.

The same can be said about Japanese Knotweed. The issue is understood, there is a reliable method for dealing with it, and so the property, and its value, should not be blighted in any way. I personally would be happy to buy such a property, and if you are a potential buyer, you should not be put off, as long the issue is known, and a plan is in place to deal with it.

Frequently, over the passage of time, new technology and understanding will provide better solutions to building issues – some of you may remember, for example, that mortgage companies in the 1980s insisted that every house should be newly damp-proofed by drilling holes all around the house near to the ground. However, now we know that a combination of better heating, insulation and ventilation will frequently cure the problem without such invasive work.”


If you believe you may have an outbreak of knotweed, or if you are interested in having your property surveyed or valued, please contact Tim Hollingsworth or any member of the Rumball Sedgwick team on on 01923 200096 or tim@rumballsedgwick.co.uk

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