I just bought a can of Zinsser Gardz for an interior project (bathroom)
and am pretty impressed with it. It is designed to seal and prime
damaged drywall so it can be patched and painted. There is nothing on
the label to suggest that it can be used for exterior applications or
for wood.

So now, I'm looking for a similar water-based product for exterior
wood. I want to use it to seal hard-to-reach places in exterior
woodwork such as the spaces between tightly-spaced-together porch floor
boards, and the area where railing posts are sitting on the porch floor
boards, to seal out water.

What I want is:

- water -based

- thin consistency so it will wick and soak into tight spaces

- forms waterproof seal

- dries clear and is paintable

- matte or satin finish (definitely not gloss)


Anybody know of a product like this?