A key stretch of the A18 Mountain Road is set to close for approximately five weeks next month to allow for what the Department of Infrastructure (DoI) has described as ‘essential construction works.’

The section between Creg ny Baa and Brandywell Corner will shut from Monday, September 15, while two new surface water culverts are installed and resurfacing works are carried out.

The roughly 3-mile closure follows earlier disruption in May, when the same area was temporarily closed after issues with the carriageway were discovered while setting up the one-way system ahead of the TT 2025.

At that time, Brandywell Corner was under investigation after surface water began leaking across the carriageway, prompting urgent repairs.

The affected area was resurfaced on May 2 after a private contractor accidentally spilled bituminous adhesive. At the time, no issues were detected.

However, water started seeping from the corner of the new surface, spreading across the road.

In September, Highway Services staff will be carrying out deep excavations up to 2.5 metres across the full width of the road, one culvert to be placed below Kate’s Cottage, and the other just south of Keppel Gate.

Around 350 metres of the road will then be fully resurfaced and re-lined.

The DoI said the work had originally been scheduled for the spring but was postponed due to a breakdown at the Department’s asphalt plant.

The closure has now been timed to take place immediately after the Manx Grand Prix, in a bid to complete the scheme before winter weather sets in.

Infrastructure Minister Dr Michelle Haywood said: ‘This scheme is vital for road safety.

‘The section of road to be worked on has seen five injury collisions in the past three years.

‘The Department has worked closely with the Isle of Man Constabulary to identify and address the issues.

‘In addition, ACU Events, the organiser of the TT, has also requested that these works be undertaken ahead of TT 2026.’

According to the DoI, the works will improve drainage and grip, making the route safer year-round, particularly during the winter months when ice risk is higher.

The additional resurfacing north of Keppel Gate, originally planned, is no longer required after recent retexturing works significantly improved grip in that area.

Dr Haywood added: ‘We apologise for any disruption this might cause motorists, but I am sure that everyone appreciates that it is essential that we should put safety first.

‘I’d like to thank motorists for their patience and understanding while we carry out these important improvements.’

Efforts will also be made to minimise any further highways works on diversion routes between Douglas and the north of the island during the closure period, to reduce traffic disruption.

Access for businesses in the area will remain in place:

  • The Victory Café, Snaefell Summit Café and Snaefell Mountain Railway will be accessible from Ramsey via Tholt y Will Road and Beinn y Phott Road.
  • The Creg ny Baa Hotel will remain reachable from Douglas via Hillberry and Creg ny Baa Road.

In addition to the five-week closure, further short-term closures are planned:

  • The northern section of the Mountain Road between Ramsey and the Bungalow will be closed on Monday, September 8 and Tuesday, September 9 for the removal of road racing equipment by contractors working for the Department for Enterprise.
  • The southern section will have its racing equipment removed from September 15, while the construction works are ongoing.
  • On Sunday, September 21, the northern section will also be closed from midday to 5pm for the Scenic Car Tour event. Arrangements will be made to shepherd vehicles participating in the event through the works area to the Creg ny Baa.

Motorists are advised to plan journeys accordingly and monitor official channels for updates.