Woodworm solution for England’s largest surviving Medieval gateway in Canterbury


Client: Canterbury City Council

Products Used: Insecticide/Fungicide Spray

Built-in 1380 Westgate Towers is England’s largest surviving Medieval Gateway. The Towers is an ancient monument and Grade I listed building, where tourists and history enthusiasts can explore the rich history of the area and take in the spectacular views of Canterbury from the battlements viewpoint. The Westgate Towers, built of Kentish ragstone, are approximately 60 foot (18m) high and are one of the city’s iconic landmarks.

The lease of Canterbury’s former City Gaol, Police Station and Westgate Towers was awarded to One Pound Lane Ltd.  They wanted to transform the area into a restaurant and bar as part of ambitious redevelopment plans for the area.

As part of a large scale restoration and redevelopment, that took place between 2015-2018, commercial timber and damp report needed to be carried out by a PCA approved property preservation specialist. Timberwise were then called to provide a timber and damp survey for this Canterbury landmark.

Timberwise’s instructions were to inspect the timbers within the property for wood rot and infestation by a wood-boring insect.  Timberwise’s trained Surveyor noted a number of types of infestation, including Common Furniture Beetle (Anobium punctatum), Wood Boring Weevil (Euophryum confine), Wet Rot Fungus (Fibroporia vaillantii) and Death Watch Beetle (Xestobium rufovillosum).

Did you know?

The Canterbury trot was the name given to the way pilgrims rode their horses to get to the city before the night-time curfew.  

The Port Cullis

The port cullis is a strong, heavy gate that can be lowered down on each side of the gateway to block the entrance. Upon arrival, Timberwise carried out a timber inspection to the large spanning lintel to the port cullis within the Guard Chamber and the upper floor timbers within the North Tower. Timberwise noted there was considerable evidence of moisture ingress, as well as surface signs of decay and mycelium.

Another day, another stunning location. What a pleasure it will be for myself and our team of technicians to do what we do best, for such a historical landmark ”

Woodworm Specialist

The North Tower

The inspection revealed an old and inactive infestation with re-infestations of wood borer activity; flight holes of recent origin were also observed denoting larval activity.

The right-hand window lintel had decayed to a structurally unsound condition and needed to be replaced immediately. Failure to do so could have resulted in serious danger for the general public visiting the tower every day. The direct cause of the fungal decay was due to timbers been built directly into the masonry with no protection against moisture absorption, providing the ideal breeding ground for dry rot.


Dry rot is often underrated and misunderstood and you can never be too cautious in dealing with an outbreak. All affected timber must be removed, brickwork sterilised. Any new timber installed, within a previous dry rot affected area must be both treated and isolated from the area of the previous outbreak.

To eradicate the fungal decay and mycelium Timberwise applied a dual purpose insecticide/fungicide surface coarse spray; this enables the fluid to penetrate the areas that cannot be accessible by brush. In addition, this fluid had no effect on the external colouration or blooming, therefore leaving the timber in its original state.

Timberwise were conscious that the recommended solution could not in any way affect the integrity of the structure. Some chemical solutions are not permitted by conservation officers. It is very important that when dealing with listed and historic buildings we are very sympathetic to the building and ensure that the solution meets the criteria laid down by the conservation officer.

The dry rot treatment was also complemented with the injection of fungicidal paste to the ends of the lintel that were in contact with the masonry. The slow acting rods give deep-rooted treatment and prevent further decay.

Need help with your property care problem?

If you have any questions about woodworm or fungal decay in your property and feel you may need us to carry out a survey, please feel free to chat directly to one of our property care team. Simply request a property survey online or click on the ‘let’s chat’ button to chat to Timberwise and we’ll help you with your property care problem. Alternatively, give us a call on 0800 288 8660.

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