Before the body was separated from the chassis I welded across the door gaps pieces of 2" box section to try and stop the body from distorting. The photos below show this and also I removed the outer sill, it shows what a bad state that the membrane between the outer sill and the inner sill is in it has almost dissolved into nothing and in places resembled lace. I kept the inner sill in place as a reference for the floor so that I could get the height correct as there was just enough remaining of the flange where the inner sill meets the floor
The floor section is a large one piece panel which has its advantages and disadvantages, it can be a bit cumbersome to move about but it does replace a large area in one go. As can be seen in the photos it is a nice panel with all the correct shapes in the floor and also the tapped holes for the seat runners. I started to remove the old floor by taking out the cross member that provides the strength across the car and also in a point where the body and the chassis bolt together. In order that the new cross member would fit in exactly the same place I pop marked the inner sill and the floor section that would remain even after the old floor was removed I was hoping to re-use the cross member but when it was removed it was too far gone to be saved.
I cut the floor out using a plasma disk in the angle grinder, these discs produce a very fine cut and don't produce much heat so reducing any distortion, the only downside is it used up one disk to cut the floor out. I used the new floor as a cutting guide and then tidied up the edges and flanges. As can be seen from the photo it leaves a big hole.
With the floor removed and sharp edges taken off it was time for a trial fit of the floor, with it being such a big panel it can be a bit tricky to move about but they are made very well and with a few adjustments made the floor lined up with the marks I had made. Once I was happy with the fit (it did take a few hours to be satisfied all line up well) I removed the floor again to remove the protective paint applied to the new panel so that it could be welded into place. (why they cannot supply them protected in weld though paint is beyond me, I would not ming having to pay a bit extra for this as it would save time and money as after the paint was removed I coated the floor with weld through primer). The same was done to the body with all traces of paint etc removed and painted in weld through primer.
In the photo below you can see the grey weld through primer which gives the metal corrosion protection but still allows you to get a good weld, it looks a bit of a mess at this stage but at least it won't rust! At this stage the floor is only tack welded in, and I will seam weld the new floor to the remaining floor section in the body once the sill have been replaced.. This will be done on both the top and the bottom to ensure a good weld and keep the water out.
The next section follows on because the sills are the next items to be replaced and have to be completed before the floor can be finished.