After a four-month trial Summit Roofguard Ltd director Sarah Beadle was found guilty of 28 various counts of unfair, misleading or aggressive commercial practices.
The jury at Wolverhampton Crown Court also decided the firm's co-director Martin Evans was guilty of 24 charges.
Summit Roofguard, which had an office in Birmingham, claimed to be the largest installer of fascias, soffits and guttering in the region. The prosecution was brought by Dudley Council's Trading Standards after customers across the Black Country were targeted by the £4 million-a-year business.
General manager Trefor Prytherch was found guilty of two counts, while employees Derrick Fisher and Glenys Bolton were each guilty of four. Afterwards, Councillor Rachel Harris, cabinet member responsible for Dudley's trading standards, said: "It is the culmination of four years of investigation and a four-month trial.
"The misleading practices and aggressive targeting methods employed by these individuals posed a risk to consumers both within Dudley and across the Midlands."
The offences were between 2011 and 2014, and the court was told the firm has ceased trading. The annual turnover was forecast to pass the £5m mark in 2012.
One of the victims was pensioner Betty Tipper, from Brierley Hill, sold windows and guttering by Summit Roofguard to replace products installed just four years earlier. Beadle and Evans were found guilty of engaging in an aggressive commercial practice in regard to Mrs Tipper.
Another pensioner targeted was 88-year-old Jack Hill, also of Brierley Hill. He was cold-called by Summit Roofguard in an attempt to persuade him to have his garage roof unnecessarily.
Beadle, Evans and Prytherch were all found guilty of engaging in an aggressive commercial practice regarding Mr Hill. Evans, aged 58, from Lower Broadheath, Worcestershire; Beadle, 39, of Yew Tree Road, Moseley; Prytherch, 57, of Crawley, Sussex; Fisher, 64, from Wootton Wawen, Warwickshire and Bolton of New Oscott, Birmingham, also 64, denied the charges.
Beadle was found not guilty of two counts, Evans of six and Prytherch of six. Not guilty verdicts were returned against all counts faced by Richard Ledwith, 38, of West Heath, Birmingham and Nadeem Yasin, 34, from Hodge Hill, Birmingham.