Really underground garage
Join Date: Aug 2010
Location: mnts of Va
Gotta back the truck up just a bit with a question...........if any moisture gets in/around the new alum sill,how is this going to impact the intregrity of the "old pitched sill"?Once that question or condition is calc'd then you can sorta proceed to next step of deciding to completely caulk or wedge with spacing.
Most of those alum sills are an extrusion......their bttms aren't flat.Instead they have vert stiffeners every cpl inches.Sometimes outter edge or lip is wider......just take that into consideration before layin a bead of caulking say,at just the outer edge.....you'll still get flex in middle.Better to fit a taper'd wedge in some instances.
Further....and this should have been a MAJOR factor before install is why an old pc of wood was going to be left under the new sill.It very well could be stout,and better quality than anything avail today(and best to leave)............or it could be that door dick didn't want to be bother'd taking it out?This also should be an influence on how the problems treated.
There could be some other factors that would lean the balance oneway or other in the proper fix.........and it can get a little confusing so will stop here.BW
Those who say it cannot be done shouldn't interrupt the people doing it.