The red brick wall, and gates which can be slotted in when needed, will protect the St Bede's and River Park areas.
Plaques Honour Cockleshell Heroes
Blue plaques have been unveiled on the houses in Southsea used by the Cockleshell Heroes as they trained for their daring mission 70 years ago.
Portsmouth City Council and the Royal Marines Association organised the plaques to mark the anniversary of the raid on Nazi-occupied Bordeaux in December 1942.
The Royal Marines trained to use canoes - the cockleshells - to access the strategically important French port which was used to supply the German army.
They were taken to the Bay of Biscay on the submarine HMS Tuna on December 7 before they paddled about 75 miles along the Gironde River until they could sneak into the port of Bordeaux and plant limpet mines on the merchant ships docked there.
Only one of the six two-man canoes made it to the port, with the others either capsizing or being captured before being executed by the Germans.
The mission, which sank one ship and severely damaged four others, was praised by Winston Churchill who said it helped shorten the war by six months.
The plaques were unveiled at houses in Spencer Road and Worthing Road in Southsea.
Ron Locke, chairman of the RMA southern region, said:
''It is important for young people to know and learn about the bravery that these men showed in this daring raid.
''The blue plaques are good as they draw attention to the fact that these were houses of importance during the Second World War.''
The unveiling of the plaques is to be followed on November 4 by a public ceremony marking the 70th anniversary of the raid.
This will see the RMA place a memorial near the Royal Marines Museum, Portsmouth, with Lord Ashdown as guest of honour and relatives of the heroes attending.
Red Jet 7 will be built at East Cowes, securing 85 jobs there - and will join the fleet next summer.
Five men have been questioned after shots were heard in Wimborne Road.
24-Year-Old Nikki Henderson Become The Youngest Ever Skipper Of A Clipper Round The World Yacht
Recently Played Tracks
Now playing: The best feel good music
Deposit £10 to get a £40 Welcome Bonus - That's £50 to play bingo, slots and more!*
Over 50 tracks to make you feel-good. New album out now...
Find your local four day weather report here.
What's happening on the roads where you are?
Make Heart the soundtrack to your day and you could be a winner with great prizes up for grabs throughout the day.
Find out more about some of the companies advertising on Heart.
Get some great ideas on how to advertise your business on radio, online and on mobile.