Welcome Michael
You can post your website here
http://constructionforums.co.uk/index.php?board=13.0 To answer your question, many years ago I had a Construction business that used time sheets and even a time clock, back in those days if I had a way of doing all this electronically I would have jumped at the chance of it. The bane of my life was quantifying time sheets every week and allocating hours to certain jobs etc.
The initial problem I see is that many construction workers are out on site and don't have access to a pc, some cannot even use a pc still, but you will get that in other industries too, so you just need to tackle that part of the problem and I am sure the rest will fall into place.
Chris