Keep three functions apart

Roof waterproofing keeps water out of the construction. A mineral protective layer adds a material layer in the zone of fire exposure. A stiff board can additionally distribute mechanical loads. One product can fulfil several tasks, but each of them needs its own technical basis.

VLOEI addresses the cement-bound route of a mineral compound spread on site. The existing roof waterproofing and its connections remain a separate function. For selection, the task of the additional layer is established first.

Binder, aggregates and fibres explain the application

In a cement-bound compound the binder reacts with water. Fine mineral aggregates determine packing and surface texture, among other things; reactive fines can influence the microstructure. Suitable fibres support cohesion and crack control. Water addition and curing affect the result.

Mineral coatings can use different binders. Water dosage, thickness, substrate preparation and curing therefore belong to the specific product. The VLOEI datasheet brings these details together.

Spray, squeegee or trowel?

Tool choice follows the specific compound, layer thickness and substrate texture. Spray application requires suitable equipment, guidance and control of the quantity applied. Squeegee or trowel application allows full-surface distribution but needs a defined layer sequence and careful connections. No method automatically makes difficult substrates easy.

With VLOEI, application by squeegee or trowel is the focus. Before a project is fixed, substrate preparation, mixing process, application rate and curing are coordinated. A controlled trial area is more meaningful for this than a blanket statement "for all roofs".

The most important limits lie in the construction sequence

A water-containing mineral compound needs a suitable application and curing window. Frost, excessively rapid drying, rain and an unsuitable substrate can impair the result. The applicable temperature and waiting time must come from the specific product specification.

Substrate movement adds to this: flexible synthetic membranes and a hardened mineral layer deform differently. Seams, movement joints, upstands and repair patches therefore need their own solutions. Granule-surfaced bitumen and smooth TPO/FPO or PVC-P membranes are not the same adhesion task.

When a board is economically more attractive

A dry-laid, suitable exterior board can avoid mixing and curing steps on the roof surface. In return, cutting, joints, contact layers and wind restraint come to the fore. With WEER on the existing waterproofing, this board concept is the focus. With new waterproofing, SHEET beneath the membrane come into consideration.

A fair calculation covers labour hours, weather interruptions, equipment, rework and later repairability. A coating can be attractive for adapted geometries; a board can have advantages on large regular areas. Our cost comparison makes these items visible.

A tight weather window makes dry-laid boards worth comparing. For an applied compound, include adhesion testing, mixing, thickness control and curing in the same estimate.

Sources and technical documents

  1. VlamShield · VLOEI technical datasheetvlamshield.nl