Reconstruction after a long-term leak problem with envelopes.
The client was in the process of replacing the flooring when, during demolition, their contractor observed staining and visible signs of moisture intrusion in the entry area. This prompted them to contact us for a comprehensive diagnostic assessment.
Below is a step-by-step summary of our investigation, findings, and corrective repairs, including technical upgrades to the building envelope and coordinated design improvements.
Below is a step-by-step summary of our investigation, findings, and corrective repairs, including technical upgrades to the building envelope and coordinated design improvements.
step 1
visual inspection.
Baseboard swelling from moisture exposure under the stairs.
Visible baseboard swelling in the under-stairs area suggests moisture absorption and material expansion, indicating likely hidden water intrusion even if the deformation appears minor.
Water-stained MDF and darkened drywall from moisture wicking.
After baseboard removal, the MDF shows clear water saturation with brown staining and visible moisture wicking. The lower drywall edge is darkened, consistent with prolonged wetting and moisture migration through the assembly.
Widespread black mold across the opened stud bay and OSB.
After opening the wall cavity and removing insulation, widespread microbial growth is visible on the OSB/sheathing, with multiple dark colonies indicating systemic bio-damage rather than isolated spotting. The affected area extends beyond the bottom plate and continues upward within the stud bay, which is consistent with long-term elevated moisture conditions and repeated wetting/drying cycles—not a one-time spill.
Rotted, moisture-damaged bottom plate with dark staining and fiber breakdown.
The bottom plate shows advanced moisture damage, with visible dark staining, fiber breakdown, and delamination consistent with early rot. Deterioration at the stud bay base indicates prolonged wetting at the floor-line, not a short-term event.
Moisture meter shows elevated wood moisture (16.4%) at the bottom plate.
Moisture meter reading at the bottom plate is 16.4% MC, which is elevated for interior framing (typical dry range ~8–12%). This indicates the assembly is still holding excess moisture and has not fully dried.
Deck boards installed tight to siding; missing flashing at door and window.
The photo shows multiple water-management deficiencies at the door/deck/wall interface and at the window opening above.
- Decking is installed tight to the wall/siding (no clearance), allowing capillary wicking and trapping water at the cladding base.
- No visible metal flashing/drip edge at the deck-to-wall transition, so runoff can migrate behind the bottom course of siding and into the lower wall joint.
- Deck surface aligns too high relative to the door threshold, increasing splash-back and direct wetting at the sill/door-to-wall connection.
- Missing head (Z) flashing above the window, leaving the horizontal joint above the unit vulnerable to water intrusion behind the cladding.
step 2
visual inspection.
Front entry under reconstruction with exposed sheathing and structural repairs in progress.
After a thorough inspection and evaluation of all contributing factors, we recommended the following immediate corrective actions:
- Remove the exterior sheathing and replace all rotted structural components, as the wall had settled approximately 3/8" at the primary leak location.
- Install proper waterproofing/WRB integration under the siding around all window openings.
- Treat all exposed framing with an antimicrobial (bio-treatment) to inhibit fungal and mold growth.
- Open the wall cavities to facilitate controlled drying of the assembly.
- Replace the front door with a more moisture-resistant (composite/PVC) unit.
- Install a sill pan/drip tray beneath the door to provide positive drainage.
- Correct exterior water management deficiencies and improve vapor barrier continuity.
- Replace the existing landing and staircase, which were structurally compromised and exhibited extensive wood rot.
- Provide proper clearance between the decking and wall cladding to ensure ventilation and prevent moisture entrapment.
An obvious mistake here is the lack of sealing between the door frame and the opening.
An obvious mistake here is the lack of sealing between the door frame and the opening. I'll explain why this is important, as the gap between the door frame and the wall is a critical transition element in the building envelope.
The sealing cord controls the depth of the sealant and allows it to stretch properly without tearing.
A high-quality sealant prevents water and air from penetrating into the wall cavity.
The waterproofing tape creates a watertight connection between the door and the vapor barrier, channeling water outward.
The connection to the vapor barrier prevents air leakage and condensation within the wall.
Without this system, water and moisture can penetrate the wall, leading to mold, rot, structural damage, and energy loss.
The sealing cord controls the depth of the sealant and allows it to stretch properly without tearing.
A high-quality sealant prevents water and air from penetrating into the wall cavity.
The waterproofing tape creates a watertight connection between the door and the vapor barrier, channeling water outward.
The connection to the vapor barrier prevents air leakage and condensation within the wall.
Without this system, water and moisture can penetrate the wall, leading to mold, rot, structural damage, and energy loss.
This photo of the window shows numerous installation and waterproofing errors that led to moisture penetration.
This photo of the window reveals multiple installation and waterproofing errors that led to moisture intrusion.
- Absence of a proper head flashing (Z-flashing).
- There is no correctly installed metal drip cap above the window to divert water away from the opening.
- Water intrusion behind the cladding.
- Rainwater running down the wall can penetrate behind the sheathing and enter the wall assembly due to improper detailing.
- Incorrect WRB (water-resistive barrier) installation.
- The waterproofing membrane is missing in certain areas, and the layering is reversed, with upper layers tucked beneath lower ones. Since water flows from top to bottom, flashing and WRB must be installed in a proper shingle-style sequence. In this case, the flashing membrane is tucked under the lower portion of the window frame, allowing rainwater to easily penetrate into the wall cavity. Additionally, the adjacent windows on both the left and right lack proper integration.
- Overreliance on sealant as primary protection.
- Sealant appears to be used as the main waterproofing method, which is improper. Caulk is a maintenance joint, not a substitute for correctly integrated flashing and drainage detailing.
Moisture-damaged window opening with missing WRB and mold.
The exposed window opening shows evidence of chronic moisture intrusion, including dark staining and early fungal growth on the OSB/sheathing. The WRB/membrane is missing or discontinuous at the jamb/sill transition, creating an uncontrolled drainage path into the wall assembly. This confirms that exterior sealant alone is not a reliable waterproofing strategy and has not prevented water from bypassing the window perimeter.
Improper door flashing and no sill pan, allowing direct water intrusion.
As demolition progressed, it became evident that the original installation lacked a proper understanding of water management principles. As anticipated, no sill pan or drainage system was installed beneath the door.
Although a metal flashing strip had been added at the deck-to-wall transition, it was installed incorrectly—the WRB/membrane was lapped behind and under the flashing rather than properly shingled over it. Additionally, the deck surface was constructed flush with the interior floor elevation, with no clearance or drainage gap. This configuration allowed water to migrate directly toward and into the door assembly without resistance.
Although a metal flashing strip had been added at the deck-to-wall transition, it was installed incorrectly—the WRB/membrane was lapped behind and under the flashing rather than properly shingled over it. Additionally, the deck surface was constructed flush with the interior floor elevation, with no clearance or drainage gap. This configuration allowed water to migrate directly toward and into the door assembly without resistance.
Improperly flashed deck ledger causing moisture intrusion and rot.
The deck ledger board was installed without proper waterproofing. A critical deficiency is the absence of a visible self-adhered membrane behind the ledger at the wall interface.
This is a classic leak-prone area. When water migrates behind the ledger board and there is no drainage or ventilation gap, moisture becomes trapped. Over time, this saturates the OSB sheathing and leads to decay of structural framing components.
This is a classic leak-prone area. When water migrates behind the ledger board and there is no drainage or ventilation gap, moisture becomes trapped. Over time, this saturates the OSB sheathing and leads to decay of structural framing components.
Severe rot at deck beam penetration due to failed flashing.
Advanced rot is visible at the penetration point of the deck support beam into the wall assembly. The deterioration is consistent with prolonged moisture intrusion due to improper flashing and waterproofing at this critical interface. Deficient workmanship in this area has resulted in significant structural damage and costly repairs—despite the home being constructed in 2015.
Severe structural rot at deck beam connection with extensive wood fiber deterioration.
The following structural framing components were found to be damaged:
Structural repairs should never be attempted without proper engineering evaluation and load management. Removal or exposure of load-bearing elements requires controlled load transfer, temporary shoring, and wall/floor support systems. Improper handling can lead to structural instability and serious safety risks.
Qualified professionals undergo years of technical training and field experience to construct and repair structural systems correctly. If you observe these warning signs in your home, consult a licensed specialist for proper assessment and remediation.
- Exterior sheathing
- Jack studs
- King studs
- Bottom plate
- Subfloor
- Rim joist
- Double top plate
- Wall studs
Structural repairs should never be attempted without proper engineering evaluation and load management. Removal or exposure of load-bearing elements requires controlled load transfer, temporary shoring, and wall/floor support systems. Improper handling can lead to structural instability and serious safety risks.
Qualified professionals undergo years of technical training and field experience to construct and repair structural systems correctly. If you observe these warning signs in your home, consult a licensed specialist for proper assessment and remediation.
It is necessary to choose a visual aid that is appropriate for the topic and audience.
We recommended the client take the following actions:
remove the exterior sheathing and remove damaged structural elements. Install waterproofing under the siding around the windows.
Create a gap between the decking and the wall with a vent. Replace the front door.
Install waterproofing under the door to remove moisture.
The client made the right decision by removing and fixing the problems with the building's enclosing structures.
remove the exterior sheathing and remove damaged structural elements. Install waterproofing under the siding around the windows.
Create a gap between the decking and the wall with a vent. Replace the front door.
Install waterproofing under the door to remove moisture.
The client made the right decision by removing and fixing the problems with the building's enclosing structures.
It is necessary to choose a visual aid that is appropriate for the topic and audience.
We recommended the client take the following actions:
remove the exterior sheathing and remove damaged structural elements. Install waterproofing under the siding around the windows.
Create a gap between the decking and the wall with a vent. Replace the front door.
Install waterproofing under the door to remove moisture.
The client made the right decision by removing and fixing the problems with the building's enclosing structures.
remove the exterior sheathing and remove damaged structural elements. Install waterproofing under the siding around the windows.
Create a gap between the decking and the wall with a vent. Replace the front door.
Install waterproofing under the door to remove moisture.
The client made the right decision by removing and fixing the problems with the building's enclosing structures.
It is necessary to choose a visual aid that is appropriate for the topic and audience.
We recommended the client take the following actions:
remove the exterior sheathing and remove damaged structural elements. Install waterproofing under the siding around the windows.
Create a gap between the decking and the wall with a vent. Replace the front door.
Install waterproofing under the door to remove moisture.
The client made the right decision by removing and fixing the problems with the building's enclosing structures.
remove the exterior sheathing and remove damaged structural elements. Install waterproofing under the siding around the windows.
Create a gap between the decking and the wall with a vent. Replace the front door.
Install waterproofing under the door to remove moisture.
The client made the right decision by removing and fixing the problems with the building's enclosing structures.
2023, HM-Pro LLC. All Rights Reserved.