Asked on Oct 23, 2017
What is the best filler for cracks in older redwood decks
by
SvonL
+1
I used a wood filler rated for exterior use, sanded and stained over the whole deck and with the next rain, those filled areas swelled up and basicaly turned to a powdery mess... total failure. What should I do now?
A mix of white wood glue with sawdust will make a paste that is perfect for fixing cracks. This would turn into some sort of "compressed wood" so to speak, and make it super hard and resistant which doesn't happen with the commercial fillers that end up cracking -as you have seen-. Add enough sawdust to the white carpenter's glue and apply. You can buy both on Amazon . Hope this helps you!
Oh! Remember to let it dry for at least 24 hours or even 48 to cure.
Really nothing much you can do. Wood expands and contracts with weather changes Wood filler and caulk does not work well for decking. There are several reasons for this. The wood filler does not “stain” to match the deck finish. This can be frustrating for someone staining a deck. No matter how hard you try, the caulk will not look like the rest of the stained surface and will stick out like a sore thumb.
Another major issue with using wood filler on a deck or wood surface is the stability of the filler. Wood filler and caulk are not stable and end up cracking or breaking out of the voids. This is especially true in an area where there is a wide range of climate change. Colder climates that freeze and thaw will cause wood filler and caulk to fail quickly.
Trying to use wood filler or caulk prior to staining will just end up looking unsightly, as the product will eventually fail anyway. The best way to deal with cracks and voids is to sand around the area to lessen the size of the crack. In extreme cases, replacing the boards or turning them over may be the best option. Otherwise, some small cracks and splits will not hurt the deck’s performance and can be stained over.
Doesn't redwood have a lot of tanin? That can keep fillers from bonding to the wood. It is true that wooden decks are always moving which is another reason why fillers fail. If you have acess to a table saw, I would suggest that you rip strips from a board and fill the larger gaps with wood. The structure beneath the gap will keep it from falling thru and you could pin it with a nail or two.