Building survey finds that fewer than one in 10 staff made use of flexible hours.
Consultants are not using flexible hours as part of their working practices, even though two-thirds of firms claim they encourage it.
The annual survey by Building of almost 500 architects, engineers, surveyors and project managers found that in more than half of firms fewer than one in 10 staff made use of the flexible hours policy.
One in five of firms said more than 20% of staff took advantage of the ability to choose their own working pattern.
There has also been little change in the number of women in the industry: in 2002 the figure for professional staff was 10%, today it is 15%.
Nearly all firms were planning recruitment drives over the next six months, and two-thirds said recruitment difficulties were holding back growth.
All but 3% said they were planning salary rises, most between 3-4%.