Flashings to upstands are carried out after laying the field membranes with
- unbacked EVALON® tapes,
- self-adhesive EVALON® VSKA tapes
- bent EVALON® coated metal sheets
11.1 Required flashing height of the roof waterproofing34
The required flashing height above the roof waterproofing or the surface paving of non-utility or utility roofs respectively (e. g. gravel layer, walkway/driveway paving or vegetation) is:
≥ 15 cm at a roof slope up to 5° (8.8 %)
≥ 10 cm at a roof slope > 5°
At door areas, it is possible to reduce the flashing height to a minimum of 5 cm, provided that unimpeded water drainage is ensured.
34 The corresponding national regulations apply.
11.2 Laying of tapes
Flashing sheets with a length of up to 25 m are laid at the required flashing height along the upstand and in the valley to the field area and are welded to the roof sealing. Vapour barriers are to be raised to the top edge of the tape.
Unbacked EVALON® tapes can be
- loose laid35 and continuously pressed on along the top edge by alwitra wall flashing profiles or
- fully bonded to the upstands on suitable substrates (contact bonding alwitra L 40) and continuously pressed on along the top edge by alwitra wall flashing profiles.
Unbacked EVALON® tapes are loose laid
- on raised vapour barriers consisting of synthetic membranes, e. g. PE foils,
- on upstands which are not rigidly connected to the supporting substrate and
- if line fastening with EVALON® coated metal sheets is installed in valleys
EVALON® VSKA tapes (see chapter 10.4) are fully bonded to the upstand on suitable substrates and at the upper edge continuously pressed on by alwitra wall flashing profiles or other suitable means.
The joint between the upstand and the wall flashing profile should be sealed with a permanently elastic and weatherproof joint sealant, using a suitable primer, if necessary.
The installation of corner waterproofing is to be made according to chapter 10.5.
35 With loose laid tapes, slight buckling cannot be excluded.
11.3 Protection of the tape
On used roofs (roof gardens, terraces, carparks), the roof sealing at the skirting must be protected against mechanical damage, also above the gravel layer, the pavement or road surface.
This can be achieved by the easy-to-install overhang profile for the alwitra wall flashing profile WA 1-ÜK or the profile WA 150. A protection layer consisting of building-protection mat36 or similar must be installed between the pavement and the roof sealing at the upstand.
36 E. g. “Regupol 9510”, BSW, Bad Berleburg, Germany. Disposal of other building-protection mats can possibly lead to slight staining and embossing at the surface of the waterproofing membranes.
11.4 Wall flashing with EVALON® coated metal sheet
Flashings to upstands can be carried out at low cost using mechanically fastened EVALON® coated metal sheets (approx. 20 cm girth, 2 bends), if line fastening is required in the valley (see chapter 7.1). Also at door areas, the flashing can be carried out best with coated metal sheets.
The connections at the joints and the fixings at the upstand must be watertight, allowing the sheets to expand and contract without damage.
The fixings, with a spacing of e ≤ 20 cm at the upstand, must be either self-sealing37 or must be covered with a seal-weld EVALON® tape.
The joint between the upstand and the coated metal sheet should be sealed with a permanently elastic and weatherproof joint sealant, using a suitable primer, if necessary. To do this, the sheets must be bent at the top edge with a side of at least 10 mm width.
37 E. g. self-sealing stainless steel screw-washer-assemblies (“plumber screws”).
11.5 Flashing to firewalls38
Walls for the separation or segregation of fire sectors (firewalls) must consist of non-combustible building materials (class A). In order to avoid thermal bridges (cooling ribs), they should be insulated above the roof level with non-combustible building materials.
You must not lay the covering over the crown of the firewall. It is recommended to loose lay unbacked EVALON® tapes of the required width (height + min. 10 cm) along the firewall and weld them to mechanically fastened EVALON® coated metal sheets.
At non-insulated firewalls made of e. g. lightweight concrete or other non-combustible materials, self-adhesive EVALON® VSKA tapes are fully bonded, fixed at the top edge against sliding away and made rainproof.
With mechanical fixing, keep the required edge distance, in particular with lightweight concrete (min. 75 mm).
38 The corresponding national regulations apply.