William McPhee, from Carfin, North Lanarkshire, previously pleaded guilty to two charges under the Consumer Protection from Unfair Trading Regulations (2008) Act.
He was jailed at Falkirk Sheriff Court as a result of a joint operation between North Lanarkshire Council, Stirling Council and Police Scotland.
McPhee was previously jailed for four years in March 2000 and for another five and a half years in August 2006, in both cases for carrying out poor quality or unnecessary work at the homes of elderly residents across Ayrshire and Lanarkshire.
Most recently, between April and May 2013, McPhee worked at two addresses in Drymen where he initially provided a quote for work then, when nearing completion, demanded more cash.
In one instance he quoted £5700 then came back looking for £11,000. In the other, he quoted £5000 and then returned asking for £18,000.
McPhee operated under the guise of a legitimate roofing company.
Trading Standards officers from Stirling Council were contacted and began an investigation that spanned Central Scotland.
Local Police Commander for Lanarkshire Division, Chief Superintendent Nelson Telfer, said: "These types of cold callers are shameful criminals.
"Anyone can be fooled by these appalling con artists, but the over 60s are often specifically targeted.
"We urge people to look out for vulnerable neighbours or family members."
Trading Standards Officers from North Lanarkshire Council are urging anyone has concerns about work done by McPhee, to contact them or the police.