This observation reinforces the importance of proper substrate preparation and a fully bonded assembly.

Dewatering Requirements for Successful Blindside Installation

Dewatering serves as both a structural support function and a waterproofing requirement. The dewatering system must provide a stable environment for installation and remain active until concrete is placed and finishes curing.

Effective dewatering should:

• Lower the water table to maintain a workable installation zone
• Intercept seepage from shoring surfaces and the excavation base
• Prevent ponding that can compromise membrane adhesion
• Include contingency plans for storms or pump cycling

Stable site conditions reduce the risk of compromised seams or detailing.

Shoring and Substrate Preparation on High Groundwater Sites

Blindside membranes bond to the surface of the shoring. Surface quality directly affects adhesion and long-term performance. Preparing the substrate improves continuity and reduces potential pathways for water movement. This includes:

• Removing loose material and sharp edges
• Filling voids or irregularities with appropriate leveling materials
• Applying shotcrete where shoring surfaces are uneven
• Ensuring mud slabs and soil bases are compacted, smooth, and free of standing water

A uniform substrate supports membrane continuity and improves concrete bonding.

Sequencing, Protection, and Trade Coordination for Blindside Waterproofing

A successful blindside installation begins with a preconstruction meeting that defines how the work will be sequenced and how trades will interact around the waterproofing. Establishing these expectations in advance helps prevent conflicts in the excavation and sets clear responsibilities for protecting the membrane once installation begins.

Blindside membranes are installed before reinforcement, utilities, and formwork, so the work sequence must protect the system at every stage. Proper sequencing ensures that trades perform their work in an order that minimizes impacts to the membrane. Coordinated access planning reduces unnecessary traffic across installed areas, and protection measures keep the membrane clean and undamaged until concrete placement.

Effective practices include:

• Restricting access to completed waterproofing zones to prevent unplanned traffic
• Providing temporary protection in areas where personnel or materials must move across the installation
• Coordinating penetrations, rebar placement, and formwork layouts before the membrane is installed
• Positioning rebar supports away from seams and detailed areas

When sequencing, protection, and coordination are established early and managed throughout the work, the membrane remains intact and continuous through concrete placement.

Inspection and Quality Control Before the Pour in Blindside Waterproofing

Because blindside membranes are concealed once concrete is placed, inspection must occur before the pour. These checkpoints confirm that the installation is ready to be enclosed and that no detailing issues remain unaddressed.

Inspection hold points should verify:

• Substrate readiness
• Initial detailing at unique conditions
• Seam continuity and attachment
• Penetration and transition detailing
• Final conditions before reinforcement and before concrete placement

These reviews reduce the risk of concealed defects and support long-term reliability. You only get one chance to get it right.

Concrete Placement and Concrete Settling

Concrete placement completes the blindside waterproofing assembly. As the concrete is placed and settles against the membrane, the mix flows into tight areas and reduces the chance of voids forming behind it.

Successful placement includes:

• Protecting adjacent membrane areas from over-splash
• Keeping the membrane clean and free of displaced material during the pour
• Maintaining dewatering until the structure can resist hydrostatic pressure

Proper settling ensures the concrete presses firmly into the membrane for a fully bonded system.

Critical Blindside Waterproofing Details in High Groundwater Conditions

Detailing is often the determining factor in blindside performance. High groundwater increases pressure at vulnerable locations and magnifies the importance of clean, continuous transitions.

“Most below-grade issues are not membrane failures,” said Jennifer Morzano, Henry® Product Manager for Below Grade Waterproofing. “They are detailing failures. High groundwater magnifies any break in continuity, which is why transitions and penetrations must be reinforced as carefully as the field membrane itself.

She said critical detailing locations include:

• Wall-to-slab transitions
• Pipe and conduit penetrations
• Inside and outside corners
• Tieback or soil anchor locations
• Construction joints and grade transitions

Concrete Placement and Consolidation for Full Bonding in Blindside Waterproofing

Concrete placement completes the blindside waterproofing assembly. As the concrete is placed and settles against the membrane, vibration is typically used to help the mix flow into tight areas and reduce the chance of voids forming behind it. Successful placement practices include:

• Protecting adjacent membrane areas from over-splash
• Keeping the membrane clean and free of displaced material during the pour
• Maintaining dewatering until the structure can resist hydrostatic pressure

Reliable Blindside Waterproofing for Zero Lot Line and High Water Table Sites

Blindside waterproofing is essential for zero lot line developments where exterior access is limited. High groundwater adds complexity by increasing hydrostatic pressure and reducing the installation margin of error. When dewatering, substrate preparation, detailing, and sequencing are coordinated effectively, Henry® blindside systems deliver durable, fully bonded protection for below-grade structures in challenging and water-driven environments.