Is exterior wood filler and a putty knife sufficient to seal nail holes through siding and housewrap?

Question

I recently tore down an old deck that was attached to the side of my house. Rather than using a ledger board, the joist hangers had been nailed directly to the plywood siding, and after removing these, I was left with a lot of nail holes. The nails were long enough to have penetrated through the plywood siding, through the housewrap, into the sheathing, and finally the house's rim joist.

When I went looking for something to seal these holes, I was directed towards an exterior wood filler that came in a squeeze tube or a can. I followed the directions to apply with a plastic putty knife, pushing the product as deep as I could into the holes, and leaving it mounded up slightly from the siding, to be sanded down and painted .

It seems like I couldn't possibly have consistently pushed the wood filler all the way through the siding to the house wrap layer, using only a putty knife. I'm concerned that, though I may have sealed the outer layer of siding, any water that gets beneath the siding (at some unknown location above) could then get through the housewrap and to the sheathing and rim joist, and cause rot in the future. Is this a realistic worry? Do I need to redo the sealing job with something better?

The area will be hidden by the ledger board of the new deck, spaced off the siding by 1/2" spacers, so appearance is not a concern.

Answer 1

The paint that protects the wood siding from rot, will be the same paint that protects the filler added into the nail holes.

As long as the paint film is unbroken, stays intact, it will prevent moisture from entering the framing.

It is as any painted surface a maintenance issue. If you don't keep the paint in good order by repainting when needed any wood surface will start to decay, or wood filler in holes of wood siding.

Answer 2

If you use some turpentine and squirt it in the nail hole, the wood filler will go deeper in the nail hole. The turpentine will make wood filler more moldable while preventing instant reaction with the wood, and the turpentine will evaporate after a while. It is like lubricating the wood hole.