Home Treatment Guidance Guidance on how to: TREAT A SUSPENDED TIMBER FLOOR TO CONTROL WOODWORM
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Guidance on how to:


floorThe correct treatment of a floor for woodworm requires all of the accessible timbers surfaces that form the floor to be coated with the prescribed level of an insecticidal timber treatment formulation - commonly referred to as woodworm treatment. This means coating the top and underside of all floorboards and all sub floor timbers i.e. joists and plates. Just treating the top surface of a floor without raising floorboards to treat sub floor timbers and the undersides of the floorboards will be of little benefit since two thirds of the timber surface area forming the floor will not be treated.



There is no justification or need and very little benefit to be gained from using a timber treatment material that also contains a fungicide when treating woodworm.

Other timbers sometimes visible/present in a floor void such as timber laths supporting a ceiling below are not normally included in the treatment though some 'fall out' benefit of the treatment may be achieved. Painted or varnished timber surfaces will not benefit from treatment unless it is removed prior to fluid application to allow the 'Woodworm Treatment' to penetrate into the timber.

How much ready to use Woodworm Treatment fluid is needed to treat a floor?

The dimensions of timbers forming a suspended timber floor will vary but for an approximate guide on how many litres of ready to use Woodworm Treatment fluid will be required multiply the floor size (in metres) by 0.75

Example: Floor size - 5m x 4m = 20 x 0.75 = 15 litres (approx). If unusually large timbers are present naturally a greater amount will be required.


Woodworm Treatment process for a conventional in situ suspended timber floor

WF 1. Before work commences display appropriate warning notices at entry points into the property and treatment area to inform others what health and safety precautions should be taken before, during and after treatment. These notices should be available from the treatment fluid manufacturer.


WF 2. Turn off at the fuse board any electrical circuits in the floor areas to be treated which should include the lighting circuit for any rooms directly below. Wrap any electrical junction boxes and other vulnerable fittings in plastic and tape to prevent treatment fluid from entering. Electricity for safety lighting and if being used an electric pump should be obtained from a different circuit. Do not turn on electrical circuits in treated areas until you are satisfied that the treatment fluid is dry.


WF 3. Completely clear areas scheduled for treatment of all furniture, floor coverings, stored articles and any other movable obstructions that may be present that will restrict access to the floor.


WF 4. Carry out any necessary repairs to the floor and apply Woodworm Treatment by brush to any timber surfaces that will be concealed by the repairs.


WF 5. Unless safe access to the underside of the floor is possible from the sub-floor void or a cellar, gain access to the sub floor timbers by raising sufficient floorboards across the entire width of a room. Single boards raised the full width of a room at approximately 1 metre centres is usually sufficient.


WF 6. At ground floor level raise floorboards as near to wall plates as possible and adjacent to outside walls and solid floors. Remove dust from the top of exposed wall plates and carefully examine these more vulnerable sub-floor timbers in greater detail for the possible presence of fungal decay.


WF 7. At first floor level check that solid strutting or trimmers within the floor void do not obstruct access for the treatment.


WF 8. All timber surfaces should be cleaned of dust as far as practically possible.


WF 9. Read the label of the Woodworm Treatment material and material safety data sheet before use and take all precautions stipulated on the label including the wearing of personal protective equipment, removal of pets, food stuffs etc.


WF10. If a water based concentrate is being used dilute sufficient Woodworm Treatment Concentrate in accordance with the instructions and fix a dilute material label to the container. (Dilute material labels should be available from the manufacturer).


WF11. Make ready application equipment and using a coarse low pressure spray apply the Woodworm Treatment at the designated application rate as follows:

Start at one end of the room and through the first raised floor board opening between two joists nearest to a wall introduce the spray lance at an angle with the spray nozzle pointing up towards the underside of the adjacent floor boards. Squeeze the trigger to release the woodworm treatment and manoeuvre the lance so that all accessible surfaces of the joists, wall plates and the underside of floorboards are coated. Repeat this procedure between each of the joists in both directions for each floorboard raised ensuring that all sub floor timber surfaces are coated at the designated application rate. Prior to relaying the raised boards, the underside of each should be coated then re-fixed into position.


WF12. Finally the top surface should be swept clean and coated with the Woodworm Treatment fluid at the prescribed application rate.



Wood preservatives and wall treatment fluids are regulated under the Control of Pesticides Regulations 1986. Under these regulations it is an offence to supply, store, sell or use these chemicals unless they have the appropriate approval. Approved products are given an HSE number which must appear on the label. Essential information for the safe use of the products is also given on the label. Specifications for the supply or application of these chemicals should require that only products and processes approved under the regulations shall be used.

Contact Peter: Email - info@dampdecay.co.uk - Telephone: 015242 71794