I’ve replaced several sills over the years, but never been totally satisfied with the results. The jacking and supporting part goes fine, as does removing what’s left of the old sill, typically an 8×8 on a stone foundation. (Btw, I’m in northern VT).
Issues start when I try to lay a bed of new mortar on the existing stone foundation. I do this so the new sill will be more or less evenly supported, and to deny rodents, cold air, etc, easy entry to the basement. It never goes well. There are humps and valleys which no amount of pounding on the new sill will flatten out. Last time I tried to use a substantial excess of mortar, mixed it up thin, and used an extra heavy sledge to try to get the beam to smoosh down into the mortar. In the end the 8×8 started bouncing and created its own valleys in the mortar, and there I was with the same problem as before….
I was thinking this time of making little forms which I would run down the length of the foundation wall. I would fill them mortar, let it set, then place the sill on the hardened mortar (with some kind of sill seal). I might even make it a very thick layer (4″ – 6″) and use a 2x PT sill instead of an 8×8. It may be a pain sculpting the forms to fit around the stones, –or maybe I’ll just leave gaps and go with a stiff mix.
Anyone have experience to share on this???
Thanks, –Brian Abbott
Replies
Greetings Brian,
This post, in response to your question, will bump the thread through the 'recent discussion' listing again which will increase it's viewing.
Perhaps it will catch someone's attention that can help you with advice.
Cheers
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Brian,
I'm not a stonemason but have a couple thoughts.
If your stone foundation is drystacked, that mortar you are putting in may have to have some rebar in it to tie it together and prevent movement. So too, I would be looking towards a heavier bed (3"+) for strength.
You mentioned on the last one you added water. Not good. The more water, the more you take strength out of the concrete/mortar.
As far as setting up forms against uneven surfaces, somebody told me to try sprayfoam for filling in voids.
Don K.
EJG Homes Renovations - New Construction - Rentals
I should fill you all in, as my original post was a week ago. I went ahead with the plan I described, and it worked pretty well. In the end my concrete was 2" - 3" thick. It seems fine, though I like Don's idea of a little rebar which would have required a thicker setup.At any rate, the results we're superior to anything I've done before, and unless there's a real need for an 8x8 I will do the same thing again next time. I'll attach a picture or two. Brian
Hmmmm. Only one pic uploaded. I'll attach the second one here....