Drivers are being warned to expect night-time lane closures on the M275 from tomorrow
Only one lane will be open in either direction on the city route between 8pm and 5.30am tomorrow and Friday.
The Rudmore flyover will also be closed while the road layout is changed on the southbound carriageway.
From Monday, work will begin on waterproofing three bridges. This will mean four nights of work where one southbound lane will be closed from 8pm until 5.30am.
During the day, three lanes will open for traffic as usual.
The work is being carried out by Colas on behalf of Portsmouth City Council.
Paul Ferroni, the asset manager for Colas, said: ‘As Portsmouth only has three routes in and out of the city we’re very aware of the pressures any work on the M275 can put on the road network.
‘We’ve worked hard to schedule this next phase of work so that it will cause minimal disruption and keep all lanes open during peak hours.
‘In particular we’ve timed activity to happen alongside the work on the new Tipner junction so we can work within existing lane closures arranged for that project.’
Another night’s work will be done on August 16 to remove the contraflow system currently in place on the M275.
After the work there will be three lanes on each carriageway again but speed limits will stay in place while work on the new Tipner junction nearby continues.
More work will be carried out from August 16 but exact times have yet to be finalised.
The waterproofing work has to be done every 40 years to keep the bridge structures safe and strong.
It can only be done in good weather.