Joints
Thermal protection also depends on how board joints are executed in the actual assembly.
VlamShield SHEET · Cement-bound glass-fibre board beneath roof waterproofing
Minimal build-up.
A clear purpose.
SHEET represents a thin, cement-bound glass-fibre board beneath new roof waterproofing. The product line combines a glass-fibre carrier with the mineral principle of VLOEI. For projects where build-up height, material selection and a clearly defined protective layer need to work together.
01 · Function
Function and installed position
A new membrane opens up the area directly above the insulation for a mineral intermediate layer. SHEET addresses this position with a thin fibre composite. The membrane provides waterproofing; the glass-fibre carrier and mineral matrix form the additional layer beneath it.
SHEET is the cement-bound approach in the application area of thin barrier layers such as AllShield BarrierSheet. For each project we compare build-up height, heat transfer, joints, and the loads from installation and PV. Where stiffness and load distribution take priority, we also consider DEK.
Schematic positions, not an installation drawing. WEER and VLOEI show alternative material routes above the membrane; DEK or SHEET sits below it. The illustrated layers are not automatically combined.
What loads act here?
Heat from a PV fire
A thin mineral layer can contribute little fuel yet still transmit heat. Protecting the insulation depends on the temperature profile and the complete assembly.
Point loads and joints
Low thickness saves build-up height but limits bending stiffness. A load-bearing support and the loads from maintenance and PV mounting belong in the selection.
Moisture before waterproofing
Dry storage, sequencing and protection of open roof areas remain necessary. A layer below a new membrane is different from an exposed roof surface.
02 · Material
Material build-up
The material principle combines a hydraulically hardening cement matrix with alkali-resistant glass-fibre reinforcement. This allows a mineral layer to be placed as a coherent element beneath the new roof membrane.
- Cement-bound matrix from the VLOEI material family
- Fine mineral aggregates to adjust structure and workability
- Alkali-resistant glass-fibre carrier for cohesion and crack control
- Factory curing as the principle of the board format
03 · Installation
Installation on the roof
- 01
Select the assembly
The roof membrane, insulation and requirements for the mineral layer form the starting point. Thickness, format and surface mass are assigned to the specific project proposal.
- 02
Coordinate the board concept
The factory-cured fibre composite is intended for dry laying. Support, handling and cutting follow the selected version.
- 03
Plan joints and fixing
Board joints, edge connections and wind restraint are coordinated with the roof assembly. These details belong in the installation plan.
- 04
Install new waterproofing
The new membrane provides protection against weather and water. Connections and outlets are designed consistently as part of the waterproofing.
Joints, outlets and upstands
Outlets
Thickness and cut pieces must not obstruct drainage. The membrane remains the continuous water-carrying layer.
PV mounts
A thin fibre board is not a load-bearing board. Load distribution must suit the insulation and mounting system.
04 · Data
Material and application
Material and application
An overview of the product line. The specific version and supporting technical documents are assigned in the project proposal.
| Material principle | Cement-bound fibre composite |
|---|---|
| Reinforcement | Alkali-resistant glass-fibre carrier |
| Position | Beneath new roof waterproofing |
| Selection criteria | Build-up height, surface mass, joints and heat transfer |
| Project information | Insulation, roof membrane, PV arrangement and protection requirement |
SHEET compared
Limit the flames.
Account for the heat.
SHEET and AllShield BarrierSheet address thin mineral layers beneath new roof waterproofing. DEK adds a stiffer cover board to the comparison. Material principle, heat transfer and the complete roof assembly are decisive.
| Criterion | AllShield BarrierSheet | VlamShield SHEET | VlamShield DEK |
|---|---|---|---|
| Material principle | Mineral composite with fibre carrier | Cement-bound VLOEI material family with glass-fibre carrier | Reference: modified gypsum core with glass mats |
| Position | Beneath new roof waterproofing | Beneath new roof waterproofing | Rigid cover layer on insulation beneath a new membrane |
| Dimensions and mass | PDS: 2.5 mm / 3 kg/m², each ±10 % [1] | Specific version in the project proposal | Reference: 6.4 mm / 5.9 kg/m² or 12.7 mm / 9.8 kg/m² [4] |
| Focus | Low build-up height, prefabricated mineral layer | Thin cement-bound fibre composite | Level substrate and load distribution |
| Selection criteria | Heat transfer, joints and layer count | Build-up height, material profile and suitable construction | Additional loading, support and membrane connection |
Stopping flames does not stop all heat.
ZAG reports limited fire spread in AS-1, alongside local melting of the full 100 mm EPS thickness due to heat transfer. Acting as a flame barrier and protecting the insulation beneath are two different performances.
ZAG · AS-1, conclusions ↗Two layers — at two positions.
The Efectis test includes one 2.5 mm layer above and one below 140 mm PIR. It supports that assembly, not a general requirement to place two layers directly together.
Efectis · R000982, section 3.3 ↗Thickness needs a like-for-like comparison.
Greater thickness increases the steady-state thermal resistance at the same thermal conductivity. When comparing different materials, heat storage, moisture, joints and behaviour under fire exposure also matter. A stiffer cover board can also offer benefits for load distribution and installation.
Compare the complete version: material, position, joints, additional loads and installation. Our technical article explains the published tests and the differences between material families.
Sources for the material comparison
05 · Selection
When yes, when no
Suitable
- New roof waterproofing with a mineral intermediate layer
- Projects with limited build-up height
- Comparison of a thin fibre layer with a stiffer cover board
- Project-specific selection of material and roof assembly
Not suitable
- As standalone roof waterproofing
- As a load-bearing board without the relevant structural evidence
- As a replacement for thermal insulation
- Permanently exposed use without an appropriate material specification
06 · Questions
Questions from practice
What is SHEET for?
SHEET addresses a thin mineral intermediate layer beneath new roof waterproofing. The focus is on the fibre composite, low build-up height and interaction with insulation and membrane.
Is SHEET the same as BarrierSheet?
SHEET is VlamShield’s cement-bound approach. BarrierSheet is a separate product line from AllShield. For selection, we compare the specific version, layer position and supporting documentation.
When is a stiffer cover board a better fit?
Where load distribution and mechanical robustness are decisive, DEK is worth comparing. The added height and mass are assessed against the roof requirements.
What information does an enquiry need?
Send the area, roof assembly, proposed waterproofing, PV arrangement and programme. We compare the material options and specify the appropriate version in the project proposal.
Project enquiry for VlamShield SHEET
Your roof. The right material solution.
Send the roof build-up, area and programme. We compare the sensible options and specify the right version for your project.
Project enquiry- Roof assembly, insulation and proposed new membrane
- Available build-up height and allowable additional roof load
- Area, project location and intended installation date
- PV mounts, access routes and junction details
- Required material and roof-assembly evidence
Other product lines
