As about 2/3 of the Netherlands is below sea level the Dutch have had to find solutions for controlling as well living and working on the water. They have refined the process of building homes on the water (woonboot) mostly utilising concrete hulls, over many years. Using reinforced concrete that is not susceptible to rusting, you can see many examples of 50 year old hulls still in perfect condition.
Floating home construction - arkenbouw
In the Netherlands floating home construction (arkenbouw) usually takes place in factories that have dry docks and then towed to their mooring on the extensive waterways system. Companies such ABC Arkenbouw have a huge factory which is temperature controlled so the floating homes are built in optimum conditions with no weather problems. The finished floating home is them delivered via the waterways to the mooring. Unfortunately this means that we cannot take advantage of these facilities in the UK because it is not possible to delivery them to the location or it is too expensive.