Construction Employee Work Tracker

The reason we need this developed is to keep a clear track of sub-contractor progress on building sites. The idea would be that sub-contractors each get their own unique login and password when they begin work for our company. They would then fill this in on our site so we have a clear record of their details (Name, Address, National insurance no.) generally all the details we require to pay them and keep track of legal requirements. Once the sub-contractor has successfully signed up and input all required details he would then be able to access a project specific checklist (That as administrators we could alter and access at any time). Each checklist under a project would be a unique area of the building site such as a kitchen for example, these areas would be worth a specific amount of money and this would update their biweekly invoice. (This is to ensure that sub-contractors can not double book their work or work they have not completed. They should also be able to upload images for these areas such as photos or plot completion sheets.) There would also be an additional tab for the project for 'daywork' which should have two input boxes (one for the amount of hours, the other for their hourly rate.) These should always require an image to be uploaded (A scan of a document confirming it.) Once they have logged these areas and any dayworks this would be added to their 'invoice' total. Our payments run on a bi-weekly method that people invoice every second Tuesday and get paid the Friday of that week. This means any areas logged up until midnight Tuesday would be due to be paid on Friday however anything that is booked in after this would fall under the next payment run. We would require access to reports of every employee and which areas on what projects they have completed. So we have accurate records of any daywork scans, plot areas booked and how much needs to be paid to each contractor. It is very important that once the areas get 'checked' off on the project page that they then get disabled and the contractors name appears next to it for all other sub-contractors to see - This completely eliminates the possibility of over booking. Other specifics will be ironed out as we progress. Payment terms can be arranged, but a working prototype is essential. Timeline for the project is 1-2 months. Budget can be negotiated depending on the product we receive. Our background is we operate a ceramic wall and floor tiling company and we need an accurate way of tracking sub-contractor earnings and progress. This should give us the opportunity to see at a glance on our portal the date on which works were completed, if they have been paid, which contractor completed them and any document or image proof for each area. Any confusion on this at all I would be happy to iron out.