Dual Density Roof Roofing photo

Whether your roofing project is part of a new construction or an existing building rehabilitation or repair, you can begin maximizing your roof’s long-term durability and environmental impact as early as the design phase.

Incorporating stone wool insulation into your roof assembly provides options for enhancing acoustic performance, passive fire protection, reliable long-term R-value and dimensional stability. Moisture-tolerant properties of stone wool even allow for insulation reuse long after other roof assembly materials have reached the end of their service life.

 

 

Roof Insulation Products

Why do we need low slope roof insulation?

As heat rises, most energy loss is usually through the roofing area. Low slope roof insulation is an essential tool that can enhance the energy efficiency of a building and reduce fuel costs.

Creating more effective low slope roof barriers also offers your building further protection from the unpredictable outdoor climate, including overheating in warmer climates and rain and snow in cooler regions.

From high rise apartment blocks, to residential designs, industrial units, large commercial facilities and schools or hospitals, flat roofs are an integral part of modern building design.

Constructions such as terraces, rooftop gardens, blue roofing with water retention and roof spaces which are used for solar purposes are becoming ever more popular. This growing trend for functional roof spaces brings even more demand for effective insulation, helping to enrich the space available on top of your building.

Flat roofs are the umbrella generating spaces to live and work.

Kim Brandt

ROCKWOOL Group Product Manager
ROCKWOOL solutions for flat roofs are durable and proven by more than 40 years of use. ROCKWOOL flat roof insulation is also non-combustible and will protect you, your building and inventory if a fire occurs.

Kim Brandt

Kim Brandt, Global Product Manager, ROCKWOOL

Low Slope Roof Applications

ROCKWOOL offers product solutions for conventional roof assemblies in new construction and the re-cover or re-roof of existing building projects.

New construction:
Choose a stone wool insulated assembly for maximum fire resistance and acoustic performance. Alternatively, a hybrid insulated roof assembly that incorporates rigid foam plastic insulation allows options for added fire protection and thermal performance by using stone wool as either an insulating coverboard or as the thermal barrier.
Re-cover:
Where allowed by the local building code, a new stone wool insulated roof assembly can be installed directly over an existing assembly that has either a failed membrane system or one at the end of its service life.
Re-roof:
When a full roof assembly replacement is needed, a ROCKWOOL stone wool insulated roof can replace the existing insulation in its entirety or be placed above the existing rigid foam plastic insulation layers that are to remain.

ROCKWOOL stone wool insulation can be used in multiple ways in a roof assembly, utilizing either full-height stone wool or a hybrid approach.

Mechanically attached

  1. Roof membrane system
  2. ROCKWOOL Toprock DD
    (multiple layers as needed)
  3. Air and vapor barrier
  4. *ROCKWOOL Toprock Flute Filler
  5. Structural deck

Mechanically attached assemblies can include single-ply membranes including TPO, PVC, EPDM, KEE. 

*Flute Filler not shown - can be installed in metal deck assemblies

Toprock DD - Metal Deck - Full Height Stone Wool Assembly - Mechanically Fastened

Torch or adhesive assembly

  1. Roof membrane system
  2. ROCKWOOL Toprock DD Plus
  3. ROCKWOOL Toprock DD
    (base layer if multiple layers needed)
  4. Air and vapor barrier
  5. *ROCKWOOL Toprock Flute Filler
  6. Structural deck

Torch or adhesive applied systems for multi-ply roof assemblies including SBS, APP (modified bitumen). 
ROCKWOOL Toprock DD Plus is designed for torch applied memebrane systems, with Toprock DD unfaced insulation as additional thermal insulation in the assembly.

*Flute Filler not shown - can be installed in metal deck assemblies

Toprock DD Plus - Metal Deck - Full Height Stone Wool Assembly - Torch Applied Membrane

Cold-Adhered assembly

  1. Roof membrane system
  2. ROCKWOOL Multifix or *Toprock DD Plus 
  3. ROCKWOOL Toprock DD
    (base layer if multiple layers needed)
  4. Air and vapor barrier (varies)
  5. Structural deck

Cold-adhered assemblies including TPO, PVC and KEE; torch or adhesive applied for multi-ply roof assemblies including SBS, APP (modified bitumen).
The mineral coated fiberglass facer on ROCKWOOL Multifix is compatible with a wide range of membrance attachment methods.

*Toprock DD Plus can be used with certain attachment methods 

Multifix - Concrete Deck - Full Height Stone Wool - Cold-adhered Membrane

Insulating Coverboard

  1. Roof membrane system
  2. ROCKWOOL Multifix, Toprock DD, or Toprock DD Plus 
  3. Polyisocyanurate insulation
  4. Air and vapor barrier
  5. *ROCKWOOL Toprock Flute Filler
  6. Structural deck

Stone wool when used as the top layer as an insulated coverboard acts as a thermal
buffer for the roof membrane, increasing the acoustic performance of the assembly, and removing the need for a separate coverboard.
ROCKWOOL stone wool insulation products are components of tested and approved roof assemblies as a coverboard in Very Severe Hail rated assemblies, and in assemblies tested for wind uplift. 

*Flute Filler not shown - can be installed in metal deck assemblies

Toprock DD Plus - Metal Deck - Hybrid Roof Assembly - Coverboard - Light Membrane

Thermal Barriers

  1. Roof membrane system
  2. Coverboard
  3. Polyisocyanurate insulation
  4. ROCKWOOL Toprock DD
  5. Air and vapor barrier
  6. *ROCKWOOL Toprock Flute Filler
  7. Structural deck

When using stone wool as the base layer in the roof assembly it acts as a thermal barrier to increase the fire resistance rating of the assembly.
ROCKWOOL Toprock DD unfaced stone wool insulation is the recommended product for this application.

*Flute Filler not shown - can be installed in metal deck assemblies

Toprock DD - Metal Deck - Hybrid Roof Assembly - Thermal Barrier

Recover Assemby

  1. Roof membrane system
  2. ROCKWOOL Toprock DD, Toprock DD Plus or Multifix

Exisiting Roof Assembly

  1. Roof membrane system, to remain
  2. Coverboard, to remain
  3. Insulation, to remain
  4. Air and vapor barrier
  5. Structural deck

Where allowed by the local building code, a new stone wool insulated roof assembly can be installed directly over an existing assembly that has either a failed membrane system or one at the end of its service life.
Stone wool insulation can act as an insulating coverboard in roof recover applications.

Toprock DD - Metal Deck - Hybrid Roof Assembly - Recover Assembly Exploded View

Case Studies

The project

Wayne State University is a nationally recognized metropolitan research institution with nearly 32,000 students. Annual maintenance evaluations identified a number of buildings on the campus with leaking roofs.

The problem

This case study looks into four of these buildings that underwent a re-roof or re-cover application where ROCKWOOL’s asphalt coated stone wool insulation was installed. The result of these upgrades resolved the water penetration issues and improved the long-term thermal performance of the roof assembly.

The solution

ROCKWOOL exclusive dual-density TOPROCK DD Plus with a higher
density top layer, provided a strong point load resistance and effective
load distribution – adding durability to the new re-roof/re-cover assemblies.

In order to meet the new ASHRAE standards, the addition of stone wool
insulation was a cost effective method for Wayne State University to both repair water penetration and improve the energy efficiency of all four
buildings.

Read more about Wayne State University's Thermal Performance

 

 

Wayne State case study roofing

FAQs

How thick should flat roof insulation be?
Do you need to ventilate a warm flat roof?
What is a cold flat roof?