I found a small section of sill plate where the bottom is rotted. Can I fill this with epoxy wood filler? Will epoxy take the weight?
You can't see from the picture but the section is about 16" long and the rot goes back in a wedge shape 1/2 to 2/3 the way under the bottom of the 2x4 sill. It looks ok from the inside the basement. There will be the weight of a deck bearing down on the sill after it is fixed. Is epoxy strong enough for that weight?
Looks like it is just where a piece of bark was attached to the wood .
If you poke in and your screwdrivergoes into the wood easily, you may have woodpests.
Otherwise just pack it with a little nonshrink grout (mortar) and you will be fine.
The picture does not show how bad it is, only the back 1/3 of the sill is in contact with the foundation for this 16" section, just enough for the floor joist not to sink. I scraped a lot of rotted wood out. The rot was from a leaking deck ledger.
I used abatron liquid wood, and wood epox and it seems to have worked fine. Supposed to have compressive strength of 5500 psi. I also sprayed borate in there after scraping out the rot, and allowed it to dry thoroughly.