Ratwall technical

Metex Knowledge Base

How do rats get into buildings?

Drainage systems and pipework play a critical role in maintaining a functional home.  However, drains connect to sewers and sewers contain the rat population – which like to nest within houses.  Defective drains or pipework often lead to a rat infestation.  After all, an adult rat can fit through a 12mm horizontal gap and a round hole of 25mm diameter. The most common points of entry in a drainage system are via:

  • Built over defective drains
  • Cracked clay pipes
  • Uncapped inlet pipe
  • Soil vent pipes
  • Plastic to clay pipe joins
  • Guttering downpipes
  • The exposed leading edge of PVC pipes
  • Gaps around the edge of waste pipes
  • Flexible toilet pan connectors

One device, full protection

Most dwellings have one main drainage outlet point before connecting to the main sewer, by installing the Rat Blocker here the whole upstream drainage system is protected from Rat intrusion.

  • A – Terraced Housing
  • B – Detached Housing
  • C – Main Sewer Lines

Metex Ratwall installation instructions

Metex Ratwall installation is easiest to install from street level using the optional installation pole. Ratwall has a unique feature that ensures a low force installation by holding the Ratwall unit in compression until it is in place within the pipe. For full details, download and follow the installation instructions. All Rat Blockers should be inspected and maintained according to the installation instructions.

Installation without the installation pole

Metex Ratwall may be installed using the supplied nut and a 17mm spanner in place of the installation pole. This gives the installer the benefit of holding the unit in compression for a low force installation.

Installation into chamber inlet – orientation of the flap

Metex Ratwall is factory configured to work within a manhole chamber outlet, but can be re-configured to protect a chamber inlet. For full details, download and follow the installation instructions.

Guide to eradicating rats from a building

Fitting a Rat Blocker from Metex will prevent rats from accessing the building through the protected drains.  However, a Rat Blocker alone may not guarantee the removal of rats already in the property.  We recommend consulting a professional Pest Controller to ensure the correct measures are taken to ensure all rats are removed and cannot return.  For details of suitable professionals, see our list of Approved Installers.

Rat Blocker Maintenance is ESSENTIAL

We are often asked if Rat Blockers need servicing – the short answer is yes, BUT not for the reasons you may be thinking!

All Metex Rat Blockers supplied by Metex are high-quality robust units, manufactured from Stainless Steel and will give many years of trouble-free service.  However, drains are a hidden world that harbour, not just rats and vermin, but all sorts of other items that have been flushed away but should not be there!  Blocked drains are often caused by seemingly harmless wet wipes, also fat tipped down the drain can solidify and can cause a blockage due to a build-up or ‘fat berg’.  Therefore, every drain is at risk of blockage unless the waste that flows through it can be carefully controlled.

As a result, it is essential that all Rat Blockers are maintained at least once every year by checking and cleaning, which is also an opportunity to visually inspect the drain.  Without these annual checks, there is a risk that should a blockage occur the Rat Blocker may be incorrectly blamed.

Ease of Maintenance

Rat Blockers from Metex can be easily removed and re-installed for drain cleaning and maintenance purposes.  Ensure the installation instructions are followed carefully when re-installing the unit.

During the first three months, it is important to check that the Rat Blocker is operating correctly. During inspection the unit should be removed completely from the drain, cleaned thoroughly and its condition inspected.  All moving parts should be assessed and lubricated as necessary.  A Rat Blocker that is showing signs of wear or mechanical issues should never be refitted.  Should there be in any doubt as to whether to refit a Rat Blocker please contact us for advice.

It is recommended that a service agreement is put in place with an approved installer for the inspection and maintenance of the installed Rat Blocker.

Quality products from Metex

All Rat Blockers from Metex are high-quality stainless steel devices.  The Nordisk TX11 Rat Blocker, previously sold in the UK as the Vermend Rat Blocker has been successfully installed in over 100,000 locations which is testament to the quality and durability of this product range.