The waterproofing membranes can be fixed against wind uplift by
- ballast,
- mechanical fastening or
- bonding.
Ballast and mechanical fastening also fix build-up layers under the waterproofing membrane, which can thus be loose laid. Bonding of the waterproofing membrane is only possible if the build-up layers are stationary, and on substrates, which are suitable for the corresponding adhesive.
6.1 Wind loads at the flat roof
Wind loads at the flat roof
- mass (weight) of the ballast,
- amount of mechanical fasteners or
- amount of adhesive
for the expected wind loads must be calculated with regard to
- the location (wind zone, height),
- the dimensions of the building,
- the form/slope of the roof and
- the substrate/wall openings
and should be differentiated according to
- the centre area
- the perimeter area
- the corner area
of the roof.
The calculation has to be done as a project-related individual calculation, according to DIN EN 1991-1-4 or to the corresponding national regulations.
6.2 Waterproofing membrane loose laid with ballast
6.2.1 Types of ballast and ballast calculation
» Gravel
consisting of washed round pebbles (16/32 mm) with max. 15 % broken stones can be directly applied as ballast on EVALON® waterproofing membranes (EVALON® V / VG), without a protection layer. For higher percentages of broken stones, a protection layer must be installed (e. g. for pneumatic gravel feeding).
The thickness of the gravel layer must be at least 5 cm.
The weight of gravel (16/32 mm) is approx. 18 kg/m² (≈0.18 kN/m²) per 1 cm fill height.
In perimeter and corner areas as well as on sloped surfaces the gravel layer can be consolidated with a suitable adhesive to prevent whirling up.
» Concrete slabs/hollow grid tiles
A loose laid protection layer e. g. rot-proof fleece, building-protection mat 14 (The compatibility of materials needs to be considered.) or similar, must be placed between the roof sealing and the concrete slabs or hollow grid tiles!
Concrete slabs laid closely together, (e. g. 100 x 25 x 5 cm) have a weight of approx. 22 – 24 kg/m2 (≈0.22 – 0.24 kN/m²) per 1 cm thickness and hollow grid tiles (60 x 40 x 8 / 10 cm), filled with gravel (16/32 mm), a weight of approx. 20 kg/m² (≈0.2 kN/m²) per 1 cm thickness. The longer edge of rectangular slabs must be laid parallel to the roof edge.
» Inverted roof
The thermal insulation, made of extruded polystyrene boards with a rebated edge, is laid in a single layer directly onto the EVALON® waterproofing membranes without a separation layer. Between the thermal insulation boards and the ballast, a filter layer made of synthetic fleece (min. 140 g/m²), or a draining fleece layer, must be placed. The required thickness of the ballast15 with loose laid waterproofing membranes is calculated for wind loads according to the “Guidelines for flat roofs”, Appendix I, or in an individual calculation. If gravel is used as ballast, the gravel layer must have a thickness of at least 5 cm.
» Paving flags
Paving flags can be installed on alwitra paving slab supports, in an underlayer of gravel or chalk free grit, or in a bed of mortar (on a draining layer). Between the paving slab supports or the gravel or grit underlayer and the EVALON® waterproofing membranes, a protection layer of building-protection mat or similar should be installed. Screed or mortar layers are to be separated from the roof sealing with a double-ply PE membrane as “sliding layer”.
alwitra paving slab support with spacer PA 20 plus:
» Installation notes
Laying accessible paviours onto alwitra paving slab supports secured against reverse rotation and over-tightening is simple and largely unaffected by weather conditions. Once the waterproofing is completed, the following is applied one after the other:
- protection layer
- paving slab supports (if necessary, with support plates)
- paving slab (min. 4 cm thick)
- spacers
It is recommended that installation should commence from outlets towards perimeters, cutting slabs at the perimeters as required.
At the perimeters the paving must be permanently secured against lateral movement. An adjacent coarse gravel band is not sufficient.
The paving slab supports are located beneath the cross joint of four slabs. A slab is supported on each corner by one pad of the four supports. Along the perimeter of a paved area, paving slab supports are cut and no spacers installed.
Infinitely and individually height-adjustable up to 20 mm pads allow for tolerances in the thickness of paving slabs and substrate, so that the top surface is smooth and evenly sloped.
Individual height adjustment, both upwards and downwards, can be made with a screwdriver even after the paving has been laid, without the need for lifting the slab.
On the base plate, at the adjusting wheel of every pad, serrations are provided behind the spacer. Insert a screwdriver through the open joint into the serration and turn the adjusting wheel: clockwise rotation of the adjusting wheel will lower the pad, anti-clockwise rotation will lift the pad.
If the paving is to be installed with a lower slope than the roof waterproofing, the paving slab supports must be placed on stackable alwitra support plates 20 mm.
Note: The recommended minimum-tilt of the paviours amounts 1 %.
» Roof gardens
Between the roof garden build-up and the EVALON® waterproofing membranes, a protection layer or a membrane combination (protection / drainage / filter layer) must be installed.
The load from the garden layers16 depends on the material, the thickness and the moisture content of the draining, filter and vegetation mat. For calculating wind uplift, the load of the dry roof is to be taken.
6.2.2 Loose laying with Ballast
Protection against wind uplift17 with ballast is permissible only if the bearing capacity of the roof construction and, if necessary, the maximum deflexion for these loads have been proven.
The ballast, including protective layer, must be applied immediately after laying the waterproofing membranes (seam testing), if necessary in sections.
14 E. g. “KRAITEC protect” company Kraiburg, Salzwedel, Germany or “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.
15 Lower values indicated in admission reports for the insulation system “inverted roof” refer only to the uplift protection of the insulation boards.
16 Please ask your roof garden supplier.
17 Also for noise control.
6.3 Waterproofing membranes loose laid and mechanically fastened
6.3.1 Fastening methods and determination of the required quantity of fasteners
Loose laid EVALON® V/VG waterproofing membranes can be secured against wind uplift by mechanical fastening:
Either linear in the seam overlaps of the backed waterproofing membranes with any approved fastener
or field fastening in a grid pattern (field fastening)18
- with b/s/t field fasteners
The fastening method, as well as the required quantity of fasteners, has to be indicated in the specification. The required quantity of fasteners will be determined in an project-related individual calculation.19
In case of refurbishment, an individual calculation should be done, if necessary based on pullout tests of the fastener manufacturer.
On non-ventilated roofs, fastening of the waterproofing membrane at the same time as fastening the thermal insulation. If the insulation boards are not sufficiently secured this way (min. 2 fasteners/m²), they must be additionally fixed prior to installing the waterproofing membrane.
6.3.2 Fastening plan
If required, project-related individual calculations20 will be produced, including installation instructions, material requirements and fastening plan.
The fastening plan contains
- the dimensions of the field, perimeter and corner areas, as well as
- the required quantity of fastening elements per roof area.
With mechanical seam fastening, the membrane width(s), the chord width (top chord spacing) of the metal sheets and the position of movement joints and large roof penetrations (arcade and single rooflights, natural smoke vents) are taken into consideration. In order to draw up an individual calculation and a fastening plan, a Data Sheet confirmed by the roofing contractor will be necessary.
6.3.3 Fasteners
Prior to any application, fastening systems must be tested and certified. The selection of the fasteners (type, length) technologically depends on:
- the thickness of the build-up structure
- the material of the supporting substructure (profiled steel decking, timber deck, derived timber product, cement or lightweight concrete)
- the strength of the substrate
- the corrosion impact from the build-up structure (especially in the case of refurbishment)
The instructions of the fastener manufacturer are to be only tread resistant fastening systems must be used.
6.3.4 Mechanical fastening in the seam area
Especially in corner areas, fasteners may be necessary outside the seam overlap, for example in the middle of the membrane. The fasteners outside the overlap area are covered by seal-welding
either in a row with unbacked tapes (16 cm wide)
or individually with round unbacked preformed EVALON® details, diameter at least 16 cm
You may, however, also use field fasteners (see chapter 6.3.5).
» Position of the fasteners
Load distribution plates must be installed at least 1 cm from the edge of the backing, rectangular load distribution plates with the longer edge being parallel to the membrane edge.
EVALON® waterproofing membranes are marked with several dashed lines along one longitudinal side. This marking can be used as a guiding line for the corresponding lap width and is
- approx. 11 cm for load distribution plates 40 x 82 mm,
- approx. 12 cm for load distribution plates Ø 50 mm.
The fasteners must be driven in only so far as to permanently prevent rotation of the load distribution plates and to ensure that the latter press the waterproofing membranes against the substrate without wrinkles.
» Use of setting tools
For an efficient and highly safe fastening in an ergonomical working position, setting tools may be used. Use only setting tools with a bit stop or a dynamometric clutch.
6.3.5 Mechanical fastening with b/s/t field fasteners
After the waterproofing membranes have been loose laid as described in chapter 6.2.2, the fastening is done as follows:
1 Line out22 the corresponding fastening grid pattern on the roof sealing for the field, perimeter and corner area in accordance with the b/s/t fastening plan.
2 Apply a circle of EVALON® liquid (approx. 6 g) onto the roof sealing around the fixing point. The membrane surface and the field fasteners must be dry and clean, the same requirements as for solvent welding (see chapter 5.2.1) apply.
3 Place the b/s/t field fastener onto the extension piece mounted to an electric screw driver.
4 Drive in the field fastener perpendicular to the roof waterproofing (not in the membrane seam area), into the substrate until the lower surface of the plastic plate is in full contact with the roof waterproofing and a small amount of EVALON® liquid is squeezed out evenly around the circumference of the plate. The plastic plate is seal-welded to the roof sealing on its complete lower surface (approx. 50 cm²).
If EVALON® VG is applied directly onto unbacked polystyrene boards, a sealing ring (on demand) has to be pulled over the screw before assembling the fastener.
This packing ring prevents EVALON® liquid coming into contact with the polystyrene.
In addition, the instructions of the manufacturer (b/s/t) need to be considered.
18 For application the respective manufacturer‘s installation instructions apply.
19 On request, as a service of the fastener manufacturer.
20 By the individual calculation of the respective manufacturer.
21 See also 4.1 “Tips for installation”.
22 Line-out with white chalk.
6.4 EVALON® waterproofing membranes bonded
Bonding of the roof waterproofing is only recommended if loose laying with ballast, or mechanical fastening is not possible. Bonding of the roof waterproofing is only possible provided that all underlying functional layers are permanently stationary (Testing before refurbishment!).
For bonding, use fleece backed waterproofing membranes EVALON® V/VG or EVALON® VSK/VGSK with a self-adhesive coating.23 The laying of EVALON® V waterproofing membranes is done either by rolling or folding, after applying the adhesive onto the substrate (generally bituminous felt).
After removal of the separation foil, EVALON® VSK or VGSK is laid as described in chapter 6.4.5 and 6.4.6. The limited mobility of the roof waterproofing resulting from the bonding makes it necessary to be especially careful when forming dilatation joints, flashings and cappings. Dilatation stresses deriving from the roof and the layer build-up must be absorbed without causing any damage.
Overlaps of membrane type backings at the joints of thermal insulation layers must not be bonded.
Prior to expansion the roof waterproofing, non specially designed movement joints with a width of up to 5 mm are to be covered with a tape (sliding strip) with a width of 25 cm, fastened at one side.
After bonding, subsequent changes in the colour of the membrane surface cannot be excluded.
6.4.1 Preparing the substrate for refurbishment
The scope of the work necessary to prepare surfaces for refurbishment24 depends on the existing layers or plies.
Existing bitumen covering with compressed gravel ballast
Cut open or completely scrape off blisters. Remove compressed gravel ballast with appropriate tools and level the substrate. Apply a compensation layer, e. g. a bituminous felt.
Existing bitumen covering under loose gravel ballast
Remove gravel ballast and bonded, tightly adhered pebbles with appropriate tools, e. g. ‘scabbler’ or roofing plane. If necessary, even the substrate by additionally torching the surface. Level any depression (e. g. removal of blisters or folds) by applying welding tapes.
Existing bitumen covering with a sand/grit coating
Cut open or completely scrape off blisters. Level any depression (e. g. removal of blisters or folds) by applying welding tapes.
Existing synthetic membrane roof sealing
Prior to bonding to existing synthetic membrane roof sealings, consultations with the alwitra Technical Department are obligatory.
6.4.2 Adhesives
Depending on the installation temperature (season), as well as on the type and characteristics of the substrate, the following adhesives are used:
» cold-bonding adhesives
- solvent-containing synthetic adhesive alwitra L 40 rolled onto the complete surface
- moisture-curing single-component PUR adhesive alwitra PUR D, poured in lines (beads)
» hot-melt bonding adhesives
- bituminous hot-melt bonding agent 85/25, 100/25 or 115/15, brushed onto the complete surface or poured in lines (beads), elastomeric bitumen hot-melt bonding agent, brushed onto the complete surface
Cold-bonding adhesives require an installation temperature of at least +5 °C. When using hot-melt bonding adhesives, EVALON® V waterproofing membranes can be installed at lower temperatures.
Note the instructions, especially with regard to
- the substrate conditions
- the installation temperature
- the quantities to be applied in the field, perimeter and corner areas.
If the adhesive is applied in lines, the roof waterproofing at the perimeter and at openings must be ensured in order to prevent wind uplift.
Prior to bonding to weathered substrates (refurbishment), a test bonding has to be carried out to determine the behaviour of the substrate and the required amounts of adhesive.
When applying adhesives, make sure that seam laps (welding area) and membrane joints in particular are kept clean from adhesive.
Fillers or other solvent-containing adhesive compositions are not suitable for bonding EVALON® membranes.
6.4.2.1 Bonding with alwitra adhesive L 40
Technical data:
| EVALON® V unterseitig kaschiert mit Polyestervlies | EVALON® VG unterseitig kaschiert mit Glasvlies/ Polyestervlies | EVALON® VSK unterseitig kaschiert mit Polyestervlies und Selbstklebeschicht | EVALON® VGSK unterseitig kaschiert mit Glasvlies/ Polyestervlies und Selbstklebeschicht |
|
|---|---|---|---|---|
| effektive Dicke der Dichtschicht [mm] | 1,2 / 1,5 1 | |||
| Bahnenbreite [m] | ||||
| - mit einseitigem Schweißrand | 1,05 / 1,55 / 2,05 | 1,05 / 1,55 | 1,05 | 1,05 |
| - mit beidseitigem Schweißrand | 1,09 / 1,59 | 1,09 / 1,59 | ||
| Zuschnittbreiten [cm] | 54 / 79 | 54 / 79 | ||
| Fixlängen | auf Anfrage | |||
| Standardfarben | weiß/hellgrau/schiefergrau | |||
| Sonderfarben 2 | auf Anfrage | |||
| Standardlängen [m] | 25 | |||
| Zubehör: | ||||
| EVALON®-Zuschnittbreiten [cm], unkaschiert 3 | 16 / 20 / 25 / 33 / 50 / 66 / 75 / 105 / 155 / 200 | |||
| EVALON®-Formteile | ||||
| - Innen-/Außenecken | • | • | • | • |
| - Kragen 4 | • | • | • | • |
| - Blitzschutz- und Kabeldurchführungen | • | • | • | • |
| EVALON®-Verbundblech - Tafeln 1 m x 2 m | weiß/hellgrau/schiefergrau | |||
| Klebstoffe | ||||
| - alwitra-L 40 | • | • 5 | ||
| - alwitra-PUR D | • | • 5 | ||
| alwitra-Quellschweißmittel | • | • | • | • |
| EVALON®-flüssig | • | • | • | • |
| alwitra-Dachbahnenreiniger | • | • | • | • |
| VSKA-Anschlussbahnen selbstklebend [cm] | ||||
| - mit einseitigem Schweißrand | 33 / 43 / 63 | |||
| - mit beidseitigem Schweißrand | 66 / 86 / 126 | |||
| alwitra-Haftgrund SK/SK-L | • | |||
| 1 andere Dicken auf Anfrage 2 grün, ziegelrot 3 mit transparenter Mitläuferfolie (bei Verlegung abziehen) 4 für alwitra-Flachdachabläufe und -lüfter 5 Verklebung nicht auf unkaschierter Wärmedämmung | ||||
Substrate conditions:
stable, plain, dry, clean, free from dust, grease and oil, free from separating agents.
L 40 is suitable for bonding on many standard substrates such as concrete, light weight concrete or sanded, gritted or mineral-coated bituminous felt. Bonding on PUR/PIR rigid foam boards with L 40 is not permissible.
Application:
Thoroughly stir the adhesive in the container (25 kg or 9.5 kg).
The adhesive is applied
- on one side, rolled onto the complete surface in a grid pattern (one-side bonding)
- on two sides, rolled onto the complete surface in a grid pattern (contact bonding)
Minimum quantity of alwitra adhesive L 40*
- for one-side bonding
| EVALON® V with polyester fleece backing | EVALON® VG with glass/ polyester fleece backing | EVALON® VSK with polyester fleece backing and self-adhesive coating | EVALON® VGSK with glass/ polyester fleece backing and self-adhesive coating |
|
|---|---|---|---|---|
| effective thickness of waterproofing layer [mm] | 1.2 / 1.5 1 | |||
| Membrane widths [m] | ||||
| - with welding lap on one side | 1.05 / 1.55 / 2.05 | 1.05 / 1.55 | 1.05 | |
| - with welding lap on both sides | 1.09 / 1.59 | 1.09 / 1.59 | 1.05 | |
| Tape widths [cm] | 54 / 79 | |||
| Standard length [m] | 25 | |||
| Specified lenghts | on request | |||
| Standard colours | white / light grey / slate grey | |||
| Special colours2 | on request | |||
| Accessories: | ||||
| EVALON® tape widths [cm], unbacked 3 | 16 / 20 / 25 / 33 / 50 / 66 / 75 / 105 / 155 / 200 | |||
| EVALON® preformed details | ||||
| - internal / external corners | • | |||
| - flange 4 / sleeve | • | |||
| - lightning conductor and cable penetrations | • | |||
| EVALON® coated metal sheets - sheets 1 m x 2 m | white / light grey / slate grey | |||
| Adhesives | ||||
| - alwitra L 40 | • 5 | • 5 | ||
| - alwitra PUR D | • 5 | • 5 | ||
| alwitra solvent welding agent | • | |||
| EVALON® liquid | • | |||
| alwitra membrane cleaner | • | |||
| EVALON® VSKA tapes self-adhesive [cm] | ||||
| - with welding lap on one side | 33 / 43 / 63 | |||
| - with welding lap on both sides | 66 / 86 / 126 | |||
| alwitra primer SK/SK-L | • 5 | |||
| 1 Other thicknesses on request 2 Green, brick red 3 With transparent protective foil (tear off for application) 4 For alwitra rainwater outlets and vents 5 Bonding is not possible on top of unbacked insulation |
||||
- for contact bonding, e. g. at parapets and upstands min. 450 g/m², at rough sheet piles min. 600 g/m².
The above-mentioned quantities must be increased depending on the substrate conditions, especially for rugged and absorbent substrates (e. g. gritted bituminous felt). Excessive application of adhesive (adhesive clusters) on polystyrene rigid foam boards coated with a bituminous felt may lead to funnel shaped destruction of the rigid foam.
Before the membranes are rolled or folded onto the adhesive, allow for sufficient airing of the solvent to reduce the amount of volatile solvent trapped under the waterproofing membrane to a minimum. High amounts of solvent under the waterproofing membrane may lead to temporary blisters in the membrane which will again disappear, with the volatile solvents diffusing out. The airing time depends in particular on the ambient temperature and humidity.
* Minimum quantity according to DIN EN 1991-1-4.
The so called finger test is the most practicle method for determining the right moment. If the finger test produces adhesive threads, a critical point has been reached, in many cases the wetting capability is already impaired.
After rolling or folding the waterproofing membrane onto the adhesive, it must be immediately pressed on tightly with a broom.
The position of the waterproofing membrane can be adjusted immediately after it has been rolled or folded onto the adhesive alwitra L 40 without impairing the adhesion. Again press on tightly.
Always check the adhesiveness.
The equipment is cleaned with alwitra cleaner L 40, this must also be done before longer work breaks.
6.4.2.2 Bonding with alwitra adhesive PUR D
Technical data:
| Base | styrene-butadiene rubber |
|---|---|
| Consistency | vicscous, rollable / brushable |
| Density | approx. 1.02 g/cm³ |
| Shelf life | min. 24 months |
| Storage | dry and cool, protected against direct sunlight |
| Substrate temperature | from +5 °C to +80 °C |
| Ambient temperature | from +5 °C to +40 °C |
| Adhesive temperature | min. +10 °C |
| Open time | one-side bonding: approx. 10 to 15 min contact bonding: approx. 15 to 20 min |
Substrate conditions:
stable, plain, clean, free from dust, grease and oil, free from separating agents, slightly moist to dry. If the substrate is dry, air humidity is low and temperatures are high, moisten the substrate by spraying water fog (max. 15 g/m²)!25 Sanded, gritted or mineral-coated bituminous felt.
Application:
one-side bonding, poured directly out of the container (5.5 kg / 2 kg) in lines (beads)26, approx. 50 – 60 g/m per bead. Allow for airing of the adhesive for approx. 5 – 10 minutes, then before a film can form on the adhesive bead, roll or fold the membrane onto the PUR D adhesive beads and press on with a broom. The width of the line under the pressed-on waterproofing membrane must be ≥ 4 cm.
Minimum quantity of alwitra adhesive PUR D*
| (g/m2) | |||
|---|---|---|---|
| Building height 1 | centre area / inner perimeter area | outer perimeter area | corner area |
| up to 8 m | 300 | 350 | 400 |
| over 8 up to 25 m | 350 | 450 | 500 |
| over 25 m | on request | ||
| 1 Buildings in wind zone WZ 1 + WZ 2 and terrain category II + III | |||
For fast adhesive application (up to 8 beads simultaneously) with regular spacing, the use of PUR adhesive applicators (“application trolley”) is recommended.
The tools must be cleaned e. g. with acetone before the adhesive has cured.
After rolling or folding the waterproofing membrane onto the adhesive beads, it must be immediately pressed on with a broom.
You must not correct the position of waterproofing membranes after they are rolled or folded onto the PUR D adhesive beads, as this will significantly impair adhesion.
Adhesive beads may show through the waterproofing membrane.
PUR D is only suitable for bonding of EVALON® V/VG waterproofing membranes with a fleece backing on sanded, gritted or mineral-coated bituminous felts. Bonding on unbacked rigid polystyrene foam is not permissible. PUR D is not suitable for bonding insulation materials.
* Minimum quantity according to DIN EN 1991-1-4.
6.4.2.3 Bonding with bituminous hot-melt bonding agent and by melt-on method
Technical data:
| Base | 1-component polyurethane, moisture curing |
|---|---|
| Consistency | liquid, pourable |
| Density | approx. 1.10 g/cm³ |
| Shelf life | min. 12 month |
| Storage | dry and cool, protected against direct sunlight |
| Substrate temperature | from +5 °C to +60 °C |
| Ambient temperature | from +5 °C to +40 °C |
| Adhesive temperature | min. +10 °C |
| Open time | approx. 20 min |
Substrate conditions:
- stable, plain, clean, free from dust, grease and oil, free from separating agents
- if necessary, with a bituminous priming coat
Application:
one-side full or partial brushed (brushing method) or poured application (pouring method)
Minimum quantity of adhesive*:
g/m² (number of lines/m²)
Building height1 centre area /
inner perimeter areaouter perimeter area corner area
up to 8 m 200 (4) 200 (4) 300 (6)
over 8 up to 25 m 200 (4) 300 (6) 400 (8)
over 25 m –
1 Buildings in wind zone WZ 1 + WZ 2 and terrain category II + III
* Minimum quantity according to DIN EN 1991-1-4.
The bituminous hot-melt bonding agent, with an installation temperature according to the previous table, is poured or brushed onto the substrate. The EVALON® V/VG waterproofing membranes can be rolled or folded onto the hot-melt bonding agent directly, or later, when the bonding agent is remelted by torching.
In any case, keep the upper side of the membranes and the welding edges clean from bituminous hot-melt bonding agent; do not lay the membranes against the prevailing wind direction.
On bituminous felts with a sufficiently thick bitumen coating, without sand or grit application, or on bitumen beds, EVALON® V/VG waterproofing membranes can be bonded with melt-on method. The bitumen coating or bitumen bed is melted with a suitable tool over the whole width of the membrane and the EVALON® V/VG waterproofing membrane is rolled onto the melted bitumen and pressed on.
Correcting the position of a waterproofing membrane after it has been rolled or folded onto the bituminous hot-melt bonding agent is not possible. After partial bonding, the bituminous hot-melt bonding agent may show through the waterproofing membrane.
6.4.3 Suitability of cold-bonding adhesives
With cold-bonding adhesives, pay special attention to their suitability for contact with the substrate. On substrates which have a top separation layer, e. g. a PE foil or a talcum coating, you cannot use cold-bonding adhesives. Such separation layers may be applied to bituminous felt sand on membrane-shaped backings or bituminous adhesive layers of thermal insulation boards to avoid sticking of the material on the roll or transport piles27.
| Base | oxidized bitumen | ||
|---|---|---|---|
| Softening point | 85 °C 1 | 100 °C 1 | 115 °C 2 |
| Penetration depth [0.1 mm] | 25 | 25 | 25 |
| Installation temperature | 180 °C | 200 °C | 210 °C |
| Consistency at installation temperature | liquid | ||
| 1 at roof slopes ≤ 3° 2 at roof slopes > 3° |
|||
1 also vertical surfaces (contact bonding)
2 sanded, gritted or with mineral-coated bituminous felt on the upper side
Legend: ++ especially suitable, + suitable, – not suitable
6.4.4 Installation scheme
6.4.5 Bonding with self-adhesive membranes EVALON® VSK
EVALON® VSK have a polyester fleece backing and a synthetic adhesive compound coating. They are 25 m long and are produced with an approx. 6 cm wide unbacked welding selvedge. After laying, the fleece backing functions as relaxing zones (vapour decompression, movement compensation, etc.). The coating is bitumen- and solvent-free and covered with a protective foil when delivered.
Until installation, the EVALON® VSK membranes must be stored in a dark place or covered with tarpaulin. Holes in the lower separation foil must be covered to preserve the high adhesiveness of the self-adhesive layer.
Technical data of the self-adhesive layer:
| (g/m2) | |||
|---|---|---|---|
| Building height1 | centre area / inner perimeter area | outer perimeter area | corner area |
| up to 25 m | 200 - 400 (> 10 %) | 400 - 600 (> 20 %) 1500 - 2000 (100 %) 2 | 400 - 600 (> 40 %) 1500 - 2000 (100 %) 2 |
| over 25 m | on request | ||
| 1 Buildings in wind zone WZ 1 + WZ 2 and terrain category II + III 2 on mineral-fibre insulation boards with bituminous adhesive layer. Approval of insulation manufacturer required |
|||
The bottom coating of the EVALON® VSK adheres to all standard building substrates, e. g. bituminous felts, concrete, zinc and steel sheets, aluminium and synthetic materials.
Bonding on unbacked thermal insulation boards is not permissible. A bonding facilitator such as alwitra primer SK or SK-L must be applied to the substrate. EVALON® VSK membranes can be applied, as described above, without any additional precautions at rated wind loads up to 3.5 kN/m² (Wres according to DIN EN 1991-1-4). The EVALON® VSK membranes are not suitable for the waterproofing of flashings or roof penetrations. Perimeter fastening (see chapter 7) is obligatory.
6.4.5.1 Application instructions for alwitra primer SK and SK-L
alwitra primer SK
Technical data
| Suitability of alwitra cold-bonding adhesives on | L 40 | PUR D |
|---|---|---|
| concrete | + | + |
| lightweight concrete | + | ++ |
| render, brick work | ++ 1 | – |
| steel sheet, aluminium | ++ 1 | – |
| timber-based boards | + 1 | – |
| bituminous sheets ² | ++ 1 | ++ |
| bituminous sheets, PE-foil, polyester fleece on the upper side | – | – |
| EPS / XPS rigid foam board unbacked | – | – |
| EPS rigid foam board, backed, glass fleece | – | – |
| EPS rigid foam board, backed, bituminous sheets ² | ++ 1 | ++ |
| PUR / PIR rigid foam board, unbacked, aluminium-laminated | – | – |
| PUR / PIR rigid foam board, mineral fleece backing | – | ++ |
| mineral fibre boards, unbacked | – | – |
| mineral fibre boards, bituminised | ++ 1 | – |
| mineral fibre boards, with anorganic coating | + 1 | – |
alwitra primer SK-L
Technical data
| Base | PSA adhesive, bitumen-free, solvent-free |
|---|---|
| Installation temperature | from +5 °C bis +40 °C |
| Storage | dry and cool, protected against light |
| Shelf life | min. 12 months |
Substrate conditions:
stable, plain, clean, free from dust, grease and oil, free from separating agents
Application:
Thoroughly stir the alwitra-primer SK/SK-L in the container (25 l / 10 l). Apply evenly to the complete surface with a brush or a paint roller.
Min. quantity of primer:
approx. 0.2 l/m² (wet, depending on the substrate). The applied quantities must be increased for rugged and absorbent substrates.
The primer must be completely dry before applying the EVALON® VSK/VSKA.
Note:
The alwitra primer SK-L dries faster in cool weather.
The condition of the bonding substrates and the necessity for precoating with alwitra-primer SK/SK-L (acc. to the table) may alter depending on the weather and construction site conditions. If necessary, a test bonding has to be carried out.
| Base | solvent-free emulsion, bitumen-free |
|---|---|
| Consistency | liquid, rollable / brushable |
| Colour | blue |
| Installation temperature | min. +5 °C |
| Airing time | approx. 30 min 29 (after that, the roof area can be walked on) |
| Storage | dry, cool, frost-protected |
| Shelf life | min. 12 months |
6.4.6 Bonding with self-adhesive membranes EVALON® VGSK
EVALON® VGSK waterproofing membranes have a glass/polyester fleece backing and a synthetic adhesive compound coating. The membranes have a length of 25 m, with a non-coated, approx. 5 cm wide welding edge on one side. The self-adhesive layer is bitumen-free and solvent-free and covered with a protective foil when delivered. Until installation, the EVALON® VGSK membranes must be stored in a dark place or covered with tarpaulin. Holes in the lower separation foil must be covered to preserve the high adhesiveness of the self-adhesive layer.
Technical data of the self-adhesive layer
| Base | SBS rubber, solvent-containing |
|---|---|
| Consistency | liquid, rollable / brushable |
| Colour | red |
| Installation temperature | min. +5 °C |
| Airing time | approx. 15 min 29 (after that, the roof area can be walked on) |
| Storage | dry, cool, frost-protected |
| Shelf life | min. 12 months |
The EVALON® VGSK membranes are not suitable for the waterproofing of flashings or roof penetrations. Perimeter fastening (see chapter 7) is obligatory.
6.4.6.1 Bonding on unbacked EPS rigid foam boards
EVALON® VGSK membranes can be directly bonded to stable, unbacked polystyrene EPS rigid foam boards. The substrate must be clean, dry and free from dust. The membranes are bonded directly to the thermal insulation without any primer. The lap width should be at least 6 cm (the self-adhesive layer will adhere to the overlapped membrane at a width of approx. 1 cm in the rear area), to avoid damage to the insulation material by hot air ingress or spilt solvent-welding agent. EVALON® VGSK membranes can be applied, as described above, without any additional precautions at rated wind loads up to substrate. EVALON® VSK membranes can be applied, as described above, without any additional precautions at rated wind loads up to 2.5 kN/m² (Wres according to DIN EN 1991-1-4).
6.4.6.2 Bonding on other substrates, e.g. bituminous sheets
The underside coating of the EVALON® VGSK membranes adheres in connection with alwitra primer SK or SK-L (up to rated wind loads of 3.5 kN/m²) to various substrates at the roof perimeter e. g. concrete, bituminous felt, brick work, zinc and steel sheets, aluminium and synthetic materials.
23 In flashing areas, also unbacked EVALON® waterproofing membranes can be contact-bonded with a solvent-containing adhesive to suitable substrates, or EVALON® VSKA.
24 Analysis of the roof build-up provided.
25 E. g. with an orchard sprayer.
26 Warming in a water bath will increase flowability.
27 Contact manufacturer for further information.
28 See also 4.1 “Tips for installation”
29 The airing time to a great extent depends on the quantity applied, the materials and the weather conditions.