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Sika-Trocal SGmA Ballasted Inverted Roof System

PVC waterproof system for use on ballasted roofs.

System includes:

  • Ballast/paving/green/brown surface protection (supplied by others).
  • S-Felt VS 140 filter layer.
  • XPS insulation.
  • Sika-Trocal® SGmA waterproof membrane.
  • S-felt A/T Fleece.

- Filter layer:

S-Felt VS 140:

Manufactured from polypropylene (PP). Used as a filter-layer in inverted roofs to prevent small particles from penetrating gaps and voids in the thermal insulation layer.

- Waterproof membrane:

A PVC membrane, with glass fibre reinforcement, for use in ballasted single-ply waterproof systems. The membrane contains biocides and is highly resistant to ageing, to industrial pollutants and to the bacteria that flourish in the moist layer of dirt present immediately above the membrane in ballasted roofs. It requires no maintenance throughout its service life.

The membrane is restrained by the weight of ballast, although under timber decking additional restraint such as Sika-Trocal metal discs or proprietary pressure plates may be required.

Laps are sealed with THF welding agent, with hot air sealing used at details.

- Protective layer:

S-Felt A polypropylene fleece:

Used as a protective layer beneath the waterproof sheets the fleece is loose laid with simple, loose end and side laps of minimum 100 mm. Generally, trapped at the perimeters by having the Sika-Trocal Metal profiles fixed over it.

S-Felt T polyester fleece:

When used as a protective layer over the Sika-Trocal Type SGmA waterproof sheets prior to the application of a ballasted finish, the minimum 100 mm laps should be sealed to prevent foreign matter being washed under the fleece and to also hold it in place whilst the ballast is placed. The joints should be sealed with a generous application of liquid PVC introduced into the lap and the joints consolidated by pressure applied to the top layer using either a hand roller or sandbag.

General information

Uniclass 2015

Ss_30_40_30_79 Single layer sheet inverted roof covering systemsPrimary


J42/120 Inverted roof covering

Specification data - Single layer sheet inverted roof covering systems

Product Reference

Sika-Trocal SGmA Ballasted Inverted Roof System

Protective layer

S-Felt A polypropylene fleece

S-Felt T polyester fleece

Waterproof membrane



Sika-Trocal SGmA


1.5 mm

2.0 mm





Filter layer

S-Felt VS 140


Sika-Trocal injection moulded corners

Sika-Trocal metal

Standard product features

Filter layer:

Material: Polypropylene (PP).

  • Thickness: 0.5 mm.
  • Width: 2.0 m.
  • Roll width: 2 m.
  • Roll length: 50 m.
  • Weight: 14 kg.
  • Colour: Grey.

Protective layer:

- S-Felt A polypropylene fleece:

  • Thickness: 1.9 mm.
  • Width: 2.0 m.
  • Length: 50 m.
  • Weight: 0.30 kg/m².

- S-Felt T polyester fleece:

  • Thickness: 2.5 mm.
  • Width: 2.0 m.
  • Length: 50 m.
  • Weight: 0.30 kg/m².
  • Colour: White.

Product Options

Waterproof membrane:

- Dimensions:

1.5 mm thick membrane.

  • Width: 2.0 m.
  • Mass: 1.9 kg/m².

2.0 mm thick membrane.

  • Width: 2.0 m.
  • Mass: 2.5 kg/m².


  • Sika-Trocal injection moulded corners: Pre-formed pieces for forming corners.
  • Sika-Trocal metal: 0.6 mm thick galvanized steel coated on the upper side with 0.8 mm thick layer of plasticized PVC. Coloured to match the waterproof membrane. Used to produce perimeter flashings, connections and fixings.