1955 MG Magnette getting new sills - inner and outer
Car sills replacement is a major job on most cars. The sills [that lower body under the doors] is part of the car body's main structure, and removing them to replace them, weakens the body significantly to the point that the body may warp, it becomes a floppy body. For the same reason when the sills are rusted out it makes the car structurally unsound and forces your hand to repair it properly. It is alot of work to try and square up a floppy body with no sills, it can be done though.
Classic car sill cavities very rarely got paint ..... ever. So if you can see rust bubbles on the outside, I'll bet you a hot dinner that it is 10 times worse on the inside.
The MG Magnette sills didn't look too bad from the top ...... er yeah nah, they're toast
The problem with sills on classic cars, is a lot of them have already been patched up a couple of times in the cars life, and hence very few are just a case of cutting a small square of rust out and welding in a new bit. The good news is that it is all fixable, the bad news is that your car needs to be pulled apart and a complete restoration is required.
Inner sill panel custom made and welded in place - proper jacking points put in also
This is where you need to make a decision, to fix or flick ...... for example the time it has taken to do the sills and other body restoration work required on this MG Magnette you see here in the example pics, is worth 2 to 3 times more than what ever I would get selling the car fully restored. And thats before paint, interior, wiring and mechanical work to be done. So if you can't do the work yourself, or can't afford to pay someone like me to do it, then you have to be realistic. Most people that go ahead and pay for these repairs have that passion for their favorite car, they do it for the love of it, for the entertainment value in seeing it progress from a wreck to a restored classic.

To properly replace the sills the body needs to be braced substantially to ensure it stays square. The body needs to be made a light as possible to be able to put it in up the car rottiserie, so it needs to be completely blown apart back to a bare shell. You can save money by pulling the car apart yourself, remembering though that you will need to have the skills to put it back together too. Otherwise I can do it for.
Priced from as above just to make an outer sill and weld it in, typically the work involved will will be much more than this.
All work is done at our standard hourly rate + parts + materials.