Hi,
We have experience of working on construction domain, we have worked for Australia company, who delivers solution for defect and safety management. We have built this product for them from start and maintained. I can share more details in PM, due to NDAs with the company.
We are team of professional mobile and web developers, and can create your mobile application. Though, as your old site is in ASP and access db on which we doesn't works, we will need to get some ASP developers to write web services to interact with your database. We can help in documenting those and find developer too if needed.
In which part of US you are, I am going to be in SFO from 4th June to 16th June and meet-up if convenient for both.
Thanks,
-Kuldip