I am about to start building a houseboat. I have 8 PVC pipes, 6 metres long and diameter of 355 millimetres.It looks as if two pipes will provide enough buoyance to support 1000 kilograms, but would like to get your advice.

My main problem is the method to affix the pontoons (that will be stopped at the ends with welded pvc) to the superstructure, with the most stability but with the least weakening of the pipe structural strength .

The craft will be used on a closed river estuary.