Hole under driver's feet (91 Firebird)

My floorboard under the driver's feet of my 1991 Firebird has recently rusted away. (I blame the years of leaky T-tops)
The hole is about eight inches by eight inches. Right now, the only
thing not making it a Flintstones-mobile is the carpet.
The car has low miles, runs great and I'd rather not get rid of it. However, aside from the safety issue, it won't pass a Pennsylvania inspection right now.
My question is, can the hole be patched somehow (maybe a piece welted over it?) or would the whole underside have to be replaced? Also, any idea on how much a legitimate body shop should charge for this?
Thanks in advance for any help and sorry if it's a dumb question.
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You can weld a piece over the hole or even pop rivet a piece as long as you seal it with something like a rubberized undercoating. That will pass Pa state insp.
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Not a dumb question at all... Yeah, they do it all the time on SPIKE, like Overhaulin', Trucks, etc. Just cut the hole square (or as close to it as possible) this will make fabbing a new piece a lot easier. Then grind down the edges smooth, make some good measurements, get a piece of metal and cut to size, pound the edges to overlap the body a little, then just weld it in like 69CamaroSS said, and then finish it off to remove any flange and make it look pretty.. even though no one will see it.. lol. If you are going to do it, good luck. If you want a shop to do it... take it to one you trust.. and expect it to cost a few bucks...
-Geno 1985 Blue Camaro 2.8L auto w/T-tops (aka "Tazmaro") 1988 Blue Firebird Formula 5.0L auto w/T-tops 1985 Brown Firebird 5.7L (360) 5-speed NO T-tops
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John Falcon wrote:

In Manitoba a full frame car can have a patch rivited and seam-sealed in place. A uni-body car (like your Bird) needs to have it welded in. Welding is better, but more work - check with your state safety department to find out the criteria. They'll probably want a patch of sheet metal the same thickness welded in.
To weld it in is easy, it's the seat, carpet and interior removal that'll probably bring the bill up... and you may discover the whole dang floor is rotten and you'll need more... see www.yearone.com - you can order complete floorpans... but that starts getting expensive.
Ray
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John Falcon wrote:

    As long as the flor pan support braces are good. It's just sheetmetal. A good bodyshop should only charge a few houndred to patch, seal, undercoat and paint and reinstall the carpeting.
    What should be done is the rust cut out, the patch made larger then needed. Welded from the inside, then have seam sealer put around the patch. The underside should be undercoated. The top should be atleast painted with spraypaint (to prevent rust). Charles
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