The innovation and development of the rat valve

In Europe, rat blockers are already in use and are very successful. Until recently, Britain didn’t have legislation in place in dealing with rodents. Now it is legally required that blockers and flaps are used.

Denmark has been leading the way, with 120,000 of them installed and it is expected that Britain will commit to this same number. After 10 years of developing and testing, we now know about getting the best from this product.

In Britain there is a complex network of underground drainage and, as such, rats use drains as their main thoroughfare to find food. Rat blocker material cannot be anything that rats can chew, so acid-proof stainless steel is the best option.

Rat Blocker

To make sure that the blocker meets these regulations, and also protects against rats, they undergo tests and approval at the Danish Technological Institute.

How we test

Pestprooflondon tests blockers and other products by baiting different areas. In the drain, rats check the internal surface and look for small cracks.

Rats can commonly be seen moving inside houses, usually under floorboards, or within loft insulation. However, they leave the house daily to feed. This means that the rat would pass through the Nordisk rat flap, but would be unable to return.

The Nordisk fitting is installed by Pestprooflondon engineers – there is no need for any excavation or repairs of a drain join. Since fitting, Pestprooflondon has been getting fantastic results. The demand for these devices has increased ever since.


It is recommended that the unit is serviced and cleaned annually. The valves would need removing once a year, cleaned, and all the joins checked for any friction with other parts. It can then be descaled, cleaned, and hinges treated with a lubricant that disperses water.

If they are serviced annually, then you should find that you are rat-free. We advise the dates that servicing needs to be done and can book an engineer.

You can contact Pestprooflondon regarding any of our products, fitting, and techniques so that you can witness the reason for our success with your own eyes.