Subfloor Rotting From Below
During the demolition of a fairly extensive kitchen renovation it was discovered under the ceramic tile floor near the window bump out the subfloor was rotting.
It appeared initially that it must be the coming from the windows. I suspected the vinyl windows, this was before the drywall was removed. However, the evidence shows no water staining on the back side (interior) of the sheathing where the drywall and insulation were removed.
What I did discover is the window bump out was built-over the existing patio concrete slab. The owner informed me this window bump out was an alteration to the home.
I still need to explore more but I believe there is a footing built beyond the concrete patio slab which the pressure treated floor framing is installed.
There is/was R-13 insulation in the floor, paper faced batts, paper towards the conditioned part of the home and underneath the insulation 4 or 6 mil poly.
Cannot determined at this point if there is building paper on the exterior wall sheathing or if there is an air gap between the sheathing and brick veneer.
I feel certain there are no weep holes but will need to pull back some of the landscaping.
I think the water is coming from the patio under the brick veneer and right under the sill plate that seems to be bearing on the concrete footing.
Could enough moisture be entering that would cause the subfloor to rot from the underside? Would this be a case where condensation is building up on the underside of the subfloor causing the rot even those the bulk water entering may not be making direct contact with the underside of the subfloor?
How about the solution? Remove it all and begin over with a good footing, foundation, water management detail?
Climate zone 4 – Mixed Humid
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