I have an old barn on a slab. I am going to put down sillplate with TP wood and than OSB followed by Hardiboard type of finish. When I anchor the sill plate do I allow for a slight overhang past the slab of say 1/8 inch to give the hardiboard something to rest on or do I anchor sill flush with the edge of the slab?
My concern is the open gap at the bottom. In other words if sill is flush to edge of slab even though the siding is screwed in it will be unsupported (hanging in mid air)at the bottom, a source of water entry ?? Caulk it or just wrap some Tyvek material around the bottom of OSB before securing?
Not worried about Hardi but how to best protect against water intrusion contacting and rotting OSB?
#1, any sheathing or siding needs to be at least 6" above finished grade.
The bottom plate is installed even with the edge of the slab, if it's set back from the edge waters going to come in under the wall.
The sheathing needs to run past the slab to once again keep the water from getting in.