Another seven applications are under review, including bids from the Federation of Master Builders and the National Federation of Roofing Contractors.
TrustMark chairman Ian Livsey said: 'All these applicants have shown the determination to be leaders in their particular sectors, and have willingly cooperated with us when we have requested any amendments to their systems and codes of practice.
'This means that the doors are now open for individual firms to become registered with TrustMark via these approved scheme operators.'
The Department of Trade and Industry has granted £2 million for TrustMark which runs until April 2007. From then on the scheme is expected to become self-funding with a £10 levy on each member.