Moisture under floor mat

[Scottsdale1977]

Hello my 1977 scottsdale that I have restored and keep in the garage for some reason keeps getting moisture under the rubber mat. Several times I pulled up the mat and there is moisture under it. I just usually dry the floor pans then reinstall the mat. The truck isn't drivin in the rain at all and I've even checked after I washed it and can't find any water leaks since this is the only time my truck usually gets wet. Has anyone had a similar issue? May this is one of the reasons the floor pans rust out on these trucks.
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[Matt Man]

Are both floor boards damp? Only thing I can think of is a leaking heater core, but that would only make the passenger side damp. Or maybe if you have AC, the drain is plugged up or bent maybe?

[Scottsdale1977]

Yes both sides are damp. I'm thinking of ditching the mat for carpet to see it it allows it to breath better. I'm just worried my floor is going to rot out.

[Matt Man]

Is is usually damp in your garage?

[Scottsdale1977]

Not all the time but depending on the weather it can be once in awhile.

[tucsonjwt]

I would remove the mat and any padding for awhile and see what happens. You will want to make sure that you don't have any rust on the floor anyway.

[midnight rambler]

I had the same issue with my 74 and I live in san diego. ended up pulling the rubber mats up and using por15 on it just ordered my carpet from Freds truck parts

[enaberif]

heat from driving plus cooling off is creating excess moisture. you could put some sound deadened down to help alleviate this.

[Scottsdale1977]

It's a replacement mat from lmc. Luckily I have no rust on the floors. I'm just going to order carpet for it to see if that solves the issue. The insulation under the mat was also replaced a few years ago when the truck was restored but it has foil on one side so I'm not sure if that's part of the issue too.

[motornut]

how are your seals to the kick vents,no chance of rust or leak there?