Re: Terminal rot?
This doesn't sound like a major problem. I am sure most garages in your area that undertake welding repairs will be able to help. If you don't wish to put yourself through the trouble of trailing for quotes/inspections you could look up a mobile welder in either the yellow pages or the local area phone book. From experience, this is a common rust area which due to its location suffers from the full effects of water and damp penetrating either through damaged underseal/paintwork or sealant. Whats more water can drip down from the upper bulkhead arera and accumulate in the space between the double layers. Once repaired I would recommend spraying the inner surface with an appropriate protector such as waxoyl - as well as resealing the seam-welds with weldseal. While you're getting this area attended to it might be worthwhile checking the whole length of the car where the floor meets the sills. This is another area that is prone to rusting - again the problem is mainly due the dampness penetrating the seal protecting the area where the two surfaces overlap. I recommend seam welding the joints, as this will strenghten the overall structure, and, once all sealed up and painted, perhaps make it less likely to suffer from corrosion. To ensure further proection, spray the sill/floor cavity through the appertures on the inner sills with a mixture of waxoyl and engine oil. In my opinion the rot is certainly not terminal - however you obviously have to consider at what point the repair becomes uneconomical. Best of luck.