When conducting a property survey, most homeowners ask the question as to why do surveyors check for Japanese knotweed as part of the process. And more importantly what effect this has on the outcome of the survey.
Have you ever thought about why mortgage surveyors, land managers, surveyors general and even estate agents ask their clients to do a survey of the property they are buying to find out if the property has any Japanese Knotweed?
Most people would just laugh in response to such a question. After all, how could they know where the weed is growing or how much of it is there?
Besides, this particular weed is not that common in the United States or any other part of the world. However, Japanese knotweed is becoming an increasingly common problem in the United Kingdom and other parts of Europe.
How does it affect properties?
Japanese knotweed can cause a lot of harm to properties and a property owner needs to know about this invasive plant in order to do a proper job of valuation.
Japanese knotweed causes no damage to the structure of a building, it just invades and damages the soil beneath the building which can lead to subsidence and a host of other problems.
Its reputation for causing devastating buildings means surveyors, land managers and builders are on high alert about it. Japanese knotweed spreads quickly during warm, dry summer months when its underground stem rhizomes emerge from the ground.

What should a new homeowner do?
If you are a property owner who has just moved into a newly built property, you need to make sure that you do a soil quality assessment before you do a survey or re-tender for your mortgage.
When you do a soil test, you will find out whether your neighbour’s property has Japanese knotweed. With this knowledge, you can make appropriate amendments to your property so that your neighbour’s soil does not contain this invasive plant.
A qualified assessor will be able to identify the main types of weeds that invade a property and determine if your neighbour’s garden is invaded by knotweed.
Knotweed can form huge masses that can exceed six feet in diameter. It can be found growing in every state in the US, the UK and many other countries around the world and has been responsible for widespread property damage in some areas.

How to tackle this problem?
The best method to deal with a Japanese weed is to not allow it to spread. If it is allowed to spread, it will destroy the delicate ecosystem that exists below the surface of the soil.
It will destroy existing grass and shrubs and will quickly destroy any existing garden plant that may have been growing below the level of the invasive plant. Japanese knotweed is very difficult to detect during the dormant periods between frosts because it grows below the surface.
Surveyors will visit your property and inspect it for the presence of Japanese knotweed infestation. The assessor may choose to visually inspect the property using a metal rod or he or she may utilize a specialized camera for the purpose.
The surveyors will write down the observations they make during their inspection and send them to the offices of your property insurance company. The office of property insurance will conduct its own investigation to verify the findings and ensure that your claims are valid.
What next?
Once you have received your confirmation of infestation the knotweeds will need to be removed. You can either choose to have the infested area excavated and graded so that it can be physically removed or you can opt for soil fumigation.
Both methods will result in the removal of the invasive plant, however, the graded excavations may take more time. If you choose to have your soil fumigated you will need to apply a soil fumigation management plan to the property.
Part of the surveyor’s process
When choosing a method of dealing with the knotweed issue it is important to remember that it is a perennial plant that grows up to two meters in height. Its flowers look like those of bamboo but their stems are smooth and thin which makes them difficult to identify without magnification.
They do grow up to eight meters tall and their brown-black flowers feature four-pointed tips. Its leaves appear to be pear-shaped and are highly overlapping.
To best manage this invasive plant it is best to address the issues that create it in the first place – that is, inadequate soil, inappropriate water, wind and human habitat.
In conclusion
Why Do Surveyors Check For Japanese Knotweed?
Ultimately, using a surveyor to ascertain the extent of the infestation will provide some reassurance of whether you have a problem or not and then more importantly, what plan of action you will need to put together to resolve it.
Once you have this professional advice you will be able to tackle the problem and more importantly be able to communicate with your lender if you are buying or selling the property.
Want to know more about whether surveyors check for Japanese Knotweed?
Knotweed Removal aims to provide the most up-to-date information, help and advice for YOU to make informed decisions. If you are unsure or uncertain about how to proceed, please reach out to us and we will gladly come back and advise you as best we can.
Governmental advice can be found here and the UK law covering the removal of Japanese Knotweed as stated under the Wildlife and Countryside Act 1981 can be found here.
The best means to contact us is via our email – hello@knotweedremoval.tips
Do not forget we have a library of blogs covering many areas relevant to Japanese Knotweed, our free downloadable How-to Guides and Product Reviews on the latest methods being employed to eradicate or remove Japanese Knotweed.
Knotweed Removal, UK
- This exclusive twin pack and 9L Watering Set is everything you need for clearing weeds from paths, patios and rives including areas of tarmac, concrete and block paving.
- Kills tough weeds and their roots including: Ground Elder, Nettles, Docks, Couch Grass, Japanese Knotweed, Brambles, Bracken & Ivy.
- Each box contains 3 x 8g Simple ready measured soluble doses and treats up to 75sqm. Apply at any time when weeds are showing green leaf and are actively growing.
- Sold with our durable 9L or 2 gallon capacity galvanised steel watering can with removable brass rose. Colour cannot be guaranteed. Watering can will be randomly picked and despatched.
- Keep children and pets away from treated areas until the spray has dried.
- Kills ivy japanese knotweed, saplings, brambles and nettles to the root
- Kills up to 16 tree stumps
- Contains a reusable pipette for specialist treatment of japanese knotweed
- Kills the roots so weeds don't come back
- Degraded in the soil by micro organisms
- Unique dual action fomulation, kills weeds to the root and prevents new weeds growing for up to 3 months
- Ideal for paths, drives and patios
- No measuring or mess - just add water
- Creates an invisible barrier that prevents new weeds for up to 3 months
- Children and pets need not be excluded from treated areas (once dry)
- WEED KILLER CONCENTRATE: Rootblast's strong weed killer is both super-concentrated and tough on most broad leaf and grass weeds. It's specifically designed to bring you the best results by using systematic herbicide technology. It targets weeds from the inside and kills them at their underlying roots, preventing any future growth
- GLYPHOSATE WEED KILLER: For optimal weed control, Rootblast have created a concentrate weed killer that contains 360g/l of glyphosate. Glyphosate is a broad-spectrum systemic herbicide and crop desiccant that is used by famers. It kills and destroys the weed without affecting the crop. By using glyphosate, Rootblast's weed killer is stronger and more effective than most other weed killers on the market
- GLYPHOSATE HERBICIDE: This powerful and effective weed killer is designed to target weeds such as dandelion, grasses, docks, nettles, willowherb, bindweed, woody brambles, tree stumps, ivy and more. After applying Rootblast's heavy duty weed killer, the first signs of weed control are visible when the weed leaves yellow - this can take anywhere from a few days to up to 2-4 weeks. From this 1 litre bottle of glyphosate herbicide concentrate, you can make up 50 litres of product when it's diluted
- DOCK, GRASS & DANDELION KILLER: Alongside this industrial strength weed killer, you'll receive a pair of protective gloves as well as the integral measuring device attached to the bottle. The gloves provide you with protection to ensure your experience is as easy and safe as possible. The integral measuring device is an inbuilt measuring cup, simply remove cap and carefully squeeze the container until the cup is full
- TOTAL PROTECT WEED GARDEN SPRAY: This easy to use product is available as a ready to use tough, concentrated weed killer that comes with a integral measuring device attached and protective gloves. Use by professional garden and farmers, this product can tackle your weed problem and kill the weed from the root - the ultimate weed killer!
- For use on unwanted vegetation and areas not intended to bear vegetation
- Contains 72 g/l glyphosate for effective control of annual and deep-rooted perennial garden weeds, including grasses*, docks, nettles, willowherb, dandelion and bindweed. Also suitable for woody brambles, tree stumps and Ivy.
- Coverage up to 66sqm per sachet