10 Waterproofing of parapets

10.1 Waterproofing concept for the parapet

  • For the single ply waterproofing of parapets, unbacked EVALON® waterproofing membranes or tapes of the required width (girth + min. 10 cm) are used. For full surface bonding you can also use backed EVALON® V waterproofing membranes and selfadhesive EVALON® VSKA tapes.
  • The waterproofing of parapets is always carried out “separately” from the waterproofing of the field area. The sealing of the field area should be raised approx. 5 cm up the parapet.
  • Protection against wind uplift: The edge of the waterproofing at the top of the parapet must be ensured against wind uplift.
  • The installation method and direction of the waterproofing membranes are to be determined depending on the characteristics of the building (height of the parapet, width of parapet top, building material, if necessary perimeter fastening).
  • For parapets up to 50 cm height, membranes can be loose laid without fixing on the wall. For parapets over 50 cm height, the membranes must be either fully bonded, or secured intermediately with EVALON® coated metal sheets or single fasteners (max. vertical interval 50 cm ).

Kapitel 10

The spacing between the individual fasteners must not exceed 30 cm.


10.2 Protection against wind uplift

The edge of the roof sealing at the parapet must be sealed so as to be windproof. With loose laid membranes, this is accomplished by windproof, mechanically fastened EVALON® coated metal sheet angles33, whereas fully bonded membranes, depending on the building height and edge details (edge trim, capping), may be additionally mechanically fastened in line.

Kapitel 10.2

33 E. g. by underlaying a strip of permanently elastic materials, especially at uneven substrates.


10.3 Edge protection of the roof sealing

Inner edges of the parapet must be shaped in such a way that the roof sealing can be applied without damage. EVALON® V/VG/VSKA membranes can be applied directly around cut-off edges. Non cut-off, sharp edges can be covered with a mechanically fastened EVALON® coated metal sheet angle.

Kapitel 10.3

10.4 Installation with VSKA tapes

EVALON® VSKA tapes are membrane tapes with a synthetic rubber coating (butyl) on the back. The coating is bitumen-free and solvent-free and covered with a protective foil when delivered. Until installation, the EVALON® VSKA membranes must be stored in a dark place or covered with tarpaulin. Holes in the lower separation foil must be covered.

Technical data of the coating

Fastening of coated
metal sheets in
with e. g.spacing [cm]
reinforced concrete /
solid brick
• SFS-Spike 4.8 x 25 mm
• SFS-RNR 6.3 x 25 mm
• body-bound rivet 4.8 / 26 mm
• screws 4.5 - 6 mm with dowel
lightweight concreteSFS-IGF-S-8.0 x 65 mm20
steel sheethsteel blind rivets 4 - 5 mm10
solid wood or chipboardwood screws 4.5 x 25 mm20

Kapitel 10.4

EVALON® VSKA tapes are produced with a non-coated approx. 12 cm wide welding edge on both sides (tape width 126 cm / 86 cm / 66 cm), or on one side (tape width 63 cm / 43 cm / 33 cm). Thus, a homogeneous welding of the EVALON® VSKA tapes to the roof sealing and the coated metal sheet angle is guaranteed.

The underside coating of the EVALON® VSKA tapes, in connection with the alwitra primer SK or SK-L (see chapter 6.4.5), adheres to all standard building substrates at the roof perimeter or wall flashing area, e. g. timber, concrete, bituminous felt, brick work, zinc and steel sheets, aluminium or synthetic materials. Depending on the substrate, the coating may show at the membrane surface.

EVALON® VSKA tapes can be installed at temperatures > +5 °C. Substrates must have a stable, plain surface, they must be dry and free from grease and oil. A bonding facilitator of alwitra primer SK or SK-L is to be applied onto the substrate (see chapter 6.4.5). The primer must be completely dry before applying the EVALON® VSKA tapes.

Test bonding is obligatory!

Place the EVALON® VSKA tapes in the correct position. Make sure that the non-coated welding edge is aligned so as to be homogeneously welded to the roof waterproofing after applying the tape. Remove the lower protective foil. Slightly press on the tape to remove any blisters. Then press on thoroughly to ensure reliable adhesive bonding.

Cross joints must be welded over with an unbacked tape. Appropriate measures must be taken to make the upper end of the EVALON® VSKA tapes rainproof.

Kapitel 10.4 zweites Bild

10.5 Installation of corner waterproofing

The membranes must be laid so as to have as little covering layers lying on top of each other as possible at the parapet corners. Membranes laid parallel to the parapet are butt together at the corner areas or laid around corners. The lap width at the butt joint should be approx. 10 cm.
If corners are formed with EVALON® preformed details, they are to be welded with handheld hot-air guns.

10.5.1 External corners (parapet/upstand – valley area)

  • with EVALON® preformed detail

Kapitel 10.5.1

10.5.2 Internal corner (inner top side of the parapet)

  • with EVALON® performed detail

Kapitel 10.5.2

10.5.3 Internal corners

  • continuous membrane, folded and welded

Kapitel 10.5.3

  • with EVALON® preformed detail

Kapitel 10.5.3 Bild 2