Barrett joins as managing director of E7 Building Services Limited and is charged with expanding the integrated services division.
Jarvis admitted its M&E services offering has been historically “low key” over the last 30 years.
It has operated through two separate divisions delivering a combined annual turnover of £10m.
The new-look divison now operates from a head office in Wellingborough and has undergone significant restructuring.
The M&E business employs around 100 staff including nearly 70 skilled engineers, working across most construction markets for many of the UK’s leading contractors.
Barrett has 36 years industry experience with the majority spent at T Clarke Group where he established relationships with key clients including Kier, RG Carter, SDC and Bouygues.
Mark Doyle, Jarvis CEO said: “Alastair’s appointment is key to E7BSL after a period of real change .
“He has the right pedigree to take our services division to the next level and beyond, providing a truly integrated building services offering which is what our contractor clients are asking for.”