Project: Flat Roof Replacement Astoria

RH Renovation NYC completed a total low-slope flat roof replacement and thermal insulation upgrade featuring complete legacy roof tear-off, structural plywood subdeck remediation, high-density polyisocyanurate (ISO) insulation board installation, multi-ply modified bitumen membrane laydown, and custom perimeter flashing encapsulation for a residential property located in Astoria, Queens, NYC. Low-slope residential roofs across urban Queens neighborhoods face demanding microclimatic conditions—including standing water risks from sudden heavy downpours, severe thermal expansion/contraction cycles during winter freeze-thaw periods, high wind-shear gusts, and intense summer sun exposure.

When an aging flat roof assembly suffers from membrane splitting, blistered seams, or waterlogged insulation, moisture penetrates deep into the underlying roof framing. Trapped water quickly degrades wood subdecking, rots ceiling joists, ruins interior drywall, and creates costly structural hazards. Furthermore, uninsulated flat roofs allow severe thermal bridging, driving up home heating and cooling energy expenses. This project was engineered to deliver a complete roof envelope renewal: stripping away compromised layers, installing rigid thermal insulation, heat-welding a heavy-duty modified bitumen waterproofing membrane, and sealing all parapet and wall transitions.

Comprehensive Scope of Work & Installation Methodology

To satisfy strict New York City Department of Buildings (DOB) residential building codes and national flat roofing standards, our licensed and insured Queens roofing specialists executed a multi-phase technical installation protocol:

• Complete System Tear-Off & Structural Substrate Inspection: Technicians systematically stripped away all layers of deteriorated legacy roofing, saturated insulation, and failed flashing down to the structural roof deck. A comprehensive inspection was conducted across exposed plywood sheathing and roof joists to identify and repair compromised framing.

• Subdeck Remediation & Vapor Barrier Application: Damaged or rotted subdeck boards were excised and replaced with structural CDX exterior-grade plywood sheathing. A continuous air and vapor barrier membrane was laid across the flat deck substrate to prevent indoor moisture migration into the new insulation layer.

• High-Density Rigid ISO Thermal Insulation Laydown: High-performance polyisocyanurate (ISO) insulation boards were mechanically fastened to the roof deck using heavy-duty stress plates and screws. This thermal barrier eliminates thermal bridging, increases overall energy efficiency, and provides a smooth, rigid substrate for membrane bonding.

• Multi-Ply Modified Bitumen Waterproofing Laydown: Premium polyester-reinforced elastomeric modified bitumen base and cap sheets were installed across the field using controlled torch-applied heat-welding techniques. All side and end lap seams were heat-fused under heavy roller pressure to form a monolithic, watertight barrier against standing water and ice pooling.

• Parapet Wall Transition & Custom Flashing Encapsulation: The waterproofing membrane was extended up perimeter parapet walls and mechanical curb penetrations. Heavy-gauge aluminum termination bars, step/counter-flashings, and industrial non-sag polyurethane lap sealants were integrated to prevent wind-driven rain infiltration behind the flashing edge.

• Reflective Surface Coating & Final Quality Control Inspection: A commercial-grade high-albedo elastomeric reflective aluminum coating was applied across the cured membrane to reflect harmful solar UV rays, reduce building heat absorption, and extend roof lifespan. A multi-point seam audit and water discharge test confirmed zero leakage, followed by a complete site cleanup.

Project Highlights & Technical Specifications

• Service Category: Residential Low-Slope Flat Roof Replacement, High-R Thermal Insulation & Bituminous Waterproofing Assembly

• Project Location: Astoria, Queens, New York, NY

• Core Materials Used: Structural CDX exterior-grade plywood sheathing, vapor barrier membrane, high-density polyisocyanurate (ISO) insulation boards, polyester-reinforced modified bitumen base/cap sheets, heavy-gauge aluminum termination bars, non-sag polyurethane lap sealants, and high-albedo reflective aluminum roof coating.

• Key Engineering Focus: Complete structural deck stabilization, monolithic standing water defense, high-efficiency thermal insulation, urban wind-shear uplift resistance, and NYC DOB code compliance.

Results & Homeowner Value

By combining complete legacy tear-off with high-efficiency rigid insulation and a heat-welded multi-ply modified bitumen membrane, RH Renovation NYC permanently secured the property’s flat roof envelope. The Astoria homeowners now benefit from an energy-efficient, fully weather-tight, and durable flat roof assembly built to withstand severe regional weather for decades.