Not one fancy picture or image I hope the words spark a lightbulb in someone's head :-)
Construction companies (contractors) use drawings/specifications to construct buildings. Engineers (or sometimes construction companies) meet with people who want new buildings to turn their building wishes into drawings/specification which comply with building regulations. Sometimes these people are elected government officials spending your money!
Contracts are formed based upon these two dimensional (2d) paper drawings/specifications usually with multiple contractors bidding on the contract. In Canada, Public Contracts (tenders) are awarded to the lowest bidder and all government contracts usually must be public tendered. In other places more sophisticated public tendering systems are used which in my opinion are better.
Drawings in the 80's were created by hand and as you can imagine when you go from 2D to actually building something you run into a few issues! Well what happens now? The contract is wrong! I needed an extra three thousand bags of cement! Well how much does that cost Mr. Contractor? Well who am I bidding against Mr. Owner? Moral of story "Changes to Contract" or "Change Orders" or "Cost Overruns" are always more costly because the contractor has the upper hand. Google the "Change Order Boat".
Think about bidding a contract for even a five story building that costs millions of dollars from instructions essentially that's what drawings and specs are they are building instructions. Some of us have trouble building a table with instruction!
Estimators painstakingly measure the information found on the drawings to develop quantities of material, interpret the specifications to supplement the information found on the drawings then arrive at a cost or a bid. Submitting a bid or in other words assigning a dollar value to the 2d drawings/specs (building instructions) creates a contract.
In this day and age a lot of 2d drawings are created using building information models (BIM) . A three dimension model of the entire building including all of the electrical and mechanical systems is created and contains vast amounts of information stored in basically a data base. A wall consists of metal or wood studs, gypsum board or other coverings and everything else needed. This technology is relatively new (10-15 years) and advancing in leaps and bounds.
The bottom line is it possible right now to virtually construct a building with your computer while your computer remembers what you told it. So in the end you could extract a lot of the quantities we talk of above. Rather than painstakingly determining the material quantities the bidders are given the quantities to assign material construction cost.
Now it's time for blockchain! We got numbers! Client A (account 0xA424764568755777) posts a set of specifications, 2d drawings for design intent, a BIM model and an accompanying smart contract with quantities to the blockchain forever saved for anyone to view. Contractors then evaluate the package, request clarifications, and submit a Materials Construct Cost for each Material Quantity to the blockchain forever saved for anyone to view. Essentially the blockchain would store and adminster the contract between client and contractor transparently for everyone to see.
Missed quantities, cost overruns, or change orders can now have a unit price assigned during bid or at a very least ridiculous increases in labor costs can be easily seen transparently by everyone because of course each additional cost must be entered into the blockchain.
The history of construction, various construction stats, contractor stats, client (government) stats, material costs, etc etc can all be saved in the blockchain. Transparent access to data will bring about all sorts of side businesses focused on analyzing the data.
Now time for the feedback loop, Laser scanning could be used to scan the building at various stages of construction to evaluate how much material is actually used to construct the project. Back to the blockchain with the data and the contract is complete. Materials used for bidding compared to actual materials used to construct could have automatic smart contracts built to deal with surplus or deficiency.
There are endless different contract stipulatations which could be coded and tested. Already there are teams like Agrello trying to create legally binding smart contracts and have already raised over 5000 btc through ICO at https://www.agrello.org. There are amazing people extracting and creating vast amounts of data using BIM and parametric computing. In my eyes they are on a collision course thankfully!
The key part is transparency that a blockchain can offer and the benefit is not just dollars and cents bottom line it's to the majority of us. Our tax dollars are used to build massive projects and without a doubt corruption exists in some form. Transparency is the only solution I see to corruption and blockchain gives me hope. Our money is spent and we deserve to know where each dollar is spent, blockchain can save us!