It's not Penguin. As Jesse stated, the link profile doesn't really set the site up for success. I count 8 unique linking root domains.
1 of the links is on a "links" page.
3+ of the links are some form of a on a directory page.
Another is on a members profile page.
Another is on a Free Advertising forum.
The Flash on the home page probably isn't helping either.
The site needs content (like Jesse said), and content that others in that niche would be genuinely interested in.
Think of some creative marketing campaigns you could do with "concrete repair." Maybe run a video series on the dangers of degrading concrete, create an infographic on the degrading process that concrete goes through, write a post about how to keep moisture out of concrete (or other general concrete maintenance), etc., etc.
Also - if the company would consider it, I would suggest they do a site-wide redesign. It looks like it's been a few years.