# Sheathing overlapping foundation



## woodworkbykirk (Sep 25, 2011)

overlapping it is standard construction practice. the sil should be pressure treated if no sil gasket is installed between the foiundation and mudsil first.

the easist way to help stop wicking is to run a 4" strip of blueskin or vycor first


----------



## hand drive (Apr 21, 2012)

When building I always build the floor system and 2x wall a 1/2 inch back from the foundation so the sheathing flushes at the outer edge with the foundation and the siding overlaps the foundation. If the wall framing is flush with the foundation then consider treated plywood at the bottom or use flashing against the wall that laps the one inch and use osb. 
If you do use treated plywood keep in mind that the 4x8 piece of osb when lapped over the rim joist and connected to the wall studs acts as a lateral support brace of sorts and ties the floor to the wall laterally. breaking that connection with a rip of treated plywood will weaken the lateral support of the wall to floor connection. I always sheath down over the rim and put purlin blocks at the horizontal break along the top of the sheathing because the sheathing will not reach the top plates of the wall when lapped over the rim joist...


----------



## joecaption (Nov 30, 2011)

If the wall was built to code so the siding will not be within 6" of grade then this should be a non issue.


----------



## Tham (May 27, 2012)

I never overlap sheathing below the mudsill. I start the siding 1" below (and corners).

tham


----------



## Pittsville (Jan 8, 2011)

Since I need the protection mainly on the back (interior) side of the sheathing, would it make sense to apply Vycor and wrap it around the bottom of the sheet and back up to the sill? This would be done before fastening the sheet to the wall. (See poorly drawn diagram)


----------



## hand drive (Apr 21, 2012)

Pittsville said:


> Since I need the protection mainly on the back (interior) side of the sheathing, would it make sense to apply Vycor and wrap it around the bottom of the sheet and back up to the sill? This would be done before fastening the sheet to the wall. (See poorly drawn diagram)



That should work fine but if there is ever any moisture from the face side of the sheathing above the flashing it could trap in the seat of the folds along the bottom of the sheathing. put the flashing on before the house wrap...


----------



## Pittsville (Jan 8, 2011)

I suppose I could staple of piece of sill seal to the back side of the sheet before fastening it. That would eliminate the possibility of trapping any moisture...


----------

