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Holger Blum Synopsis of the lecture given to the Roofing Trades' Guild at the 1st EVERLAST® Symposium held at Penzlin, Germany, on April 3, 1991.

By using EVERLAST®ROOFSKIN , the roofing specialist Figure1has a successful and permanent solution to the majority of problems presented by the following:
  • renewal of old, leaking flat bitumen roofs Figure2
  • elimination of inadequate windproofing on cold roofs
  • renewal of roof seals on steel sheet sections Figure3
  • elimination of cracks in the roof edge areas on flat concrete roofs Figure4
  • renewal of crack formations in the 'puddle edge' area of flat bitumen roofs
  • prevention of water leakage on corrugated asbestos cement roofs Figure5
  • renewal of light dome joints on thermal roofs Figure6
  • elimination of roof damage with foam filled steel sheet sections Figure7
  • elimination of damage to roof skin due to shrinkage of plastic foam boards
  • elimination of roof damage due to water condensation
  • roof renewal on steel sheet sections Figure8

Innumerable clients are already successfully using EVERLAST® roofing system for their new roofs, because it is by far the most favourably priced permanent ROOF SKIN™ liquid plastic on the market.

First developed for use in tropics EVERLAST®ROOFSKIN was born at the beginning of the 'seventies, at the time the United States of America were trying to find an absolutely weatherproof and permanent ROOF SKIN™ material for their installations and airfields in the tropical rain regions of East Asia - whatever the cost.

Tests conducted by NASA, the US Space Research Agency, established the chemical structure required for a base elastomer that could withstand at least 12 years' weather exposure. The roofs constructed in Eastern Asia at that time are still watertight and intact even today - after 18 years of exposure to tropical weather conditions.

Improved manufacturing method ITWAS ONLY a few years ago that it became possible - thanks to improved exploitation of raw materials and a unique, patented manufacturing process - to employ this ROOF SKIN™ material, which was originally extremely expensive (more than US $ 50 per kilogramme) in a wider field, namely repairing and refurbishing roofs. For this application, first in Hamburg was built a special production plant for this high tech elastomer now called EVERLAST®ROOFSKIN .

The permanent roof sealing method THE DURABILITY of EVERLAST®ROOFSKIN under changing climatic conditions meant it was predestined for applications where a long term solution had to be found for the problem of roof leaks , especially in the case of flat roofs. Figure9

EVERLAST® base elastomer forms a chemical bond with the undersurface when it hardens, and, due to a chemical reaction and its polaric grouping with a high dipolaric momentum, forms an adhesive layer that is virtually indestructible.This is particularly noticeable if EVERLAST®ROOFSKIN is applied to bitumen tar roofs. Figure10

After setting, the EVERLAST®ROOFSKIN surface can no longer be peeled off the bitumen surface; the bitumen is lifted off the cardboard base instead. Because EVERLAST®ROOFSKIN adheres chemically to the undersurface Figure11, it is superior to every kind of plastic coating material with physically bonding adhesives in terms of the safety of application and permanent adhesive properties on roofs!

A High-Performance Elastomer Despite its high tensile strength, EVERLAST®ROOFSKIN is a 'super-elastomeric rubber' and completely conforms to all expansion movements of the roof undersurface in an ideal way. Due to the permanent crosslinking of the chemical chains, the possibility of "creep" - as in the case of bitumen - is entirely ruled out.

The high low temperature flexibility of EVERLAST®ROOFSKIN base elastomer is a further appreciable advantage for roofing specialists. As shown by recent tests at a State plastics technology institute, only EVERLAST®ROOFSKIN was sufficiently permanently elastic at -40°C (-40°F), out of 27 known plastics for liquid application tested. The reason for this is the unique molecular structure of the base elastomer.

Due to the principle of temperature and time-superposition in the case of real elastomers, gradual stress caused by the change from night to day can create a too 'cold' environment even with light frost. The plastic affected becomes brittle and cracks, causing the roof to leak. EVERLAST®ROOFSKIN has a glass transition temperature of minus 58°C(-72°F), is safely protected against this form of material breakdown (cold fractures) and can therefore be used with advantage in climatic zones with permanent frost.

User friendly THANKS to its patented manufacturing and application process, EVERLAST®ROOFSIN is exceptionally easy to use. Ample humidity is the only factor - apart from a dry undersurface- necessary to produce a high-performance ROOF SKIN™. This is documented by our precise working instructions. For the first time ever with this kind of polyurethane material, the thickness of the EVERLAST®ROOFSKIN coat is of absolutely secondary importance.

EVERLAST®ROOFSKIN hardens perfectly, whatever the thickness of the coat (even if over 300 mm!) The problem of forces acting on the only sufficiently permanent fleece material, "100% Acrylic Fleece", has also been solved thanks to the special adhesive bond. A particular advantage offered by EVERLAST®ROOFSKIN is that it can crosslink safely even in frost, and can therefore be applied the whole year round.

EVERLAST®ROOFSKIN roofing system was developed specially to cope with the hard demands placed by building-construction engineers. Construction specialists and physicists developed and formulated the directives for the practical application of EVERLAST® .

Superior longlasting-roof sealing
EVERLAST®ROOFSKIN roofing system is unique. Although silver-coloured polyurethane materials - flooring grade polyurethanes, are sometimes misused for roof surfacing, the advantages offered by EVERLAST®ROOFSKIN , from its price right down to its low temperature flexibility, can stand up to any neutral comparison. This is because, as was previously mentioned, EVERLAST®ROOFSKIN base elastomer was exclusively and specially developed for the constructional requirements of a ROOF SKIN™.
  • • For architects, roofing specialists and planning engineers, EVERLAST®ROOFSKIN roofing system provides an economical and safe alternative for complete roof refurbishment -i.e. removing the roof covering and thermal insulation and subsequent renewal.Figure12 , Figure13 , Figure 14
  • • Try the EVERLAST®ROOFSKIN test: a corrugated asbestos board , 95 mm wide and one corrugation long (i.e. 170 mm long) , coated with EVERLAST®ROOFSKIN is placed on the floor and heavily trodden on. The result: the corrugated asbestos breaks, but remains in one piece, thanks to its elastic bond.
  • • The same proof of EVERLAST®ROOFSKIN performance is seen if the coated corrugated asbestos board is previously stored over night in a freezer at -30°C (-22°F)and if this cold board is then stepped on in the same way. Here, too, the bond remains intact!

Seal everything with just one material MANY LEAKAGE problems on roofs are caused by the number of edges, protrusions, hatches, aerial and lightning conductor brackets. The problems, which are caused by the presence of materials with varying thermal coefficients of expansion, can easily be remedied with EVERLAST®ROOFSKIN roofing system . Figure15 , Figure16

Because even thickly coated sections dry out (cure)without problems, a paste made out of EVERLAST®ROOFSKIN and short fibres is ideal for producing seamless joints. Instead of tiresome methods involving sealing or potting compounds , the roofer can now coat the roof surface and the joins and butts with just one material - EVERLAST®ROOFSKIN - with a minimum of work. Figure17, Figure 18

Figure 1: Roofer inspecting his Flatroof, sealed with EVERLAST®ROOFSKIN.
Figure 2:Restoring an old bitumen felt roof with EVERLAST®ROOFSKIN.
Figure 3: Renewal of roof seals on steel sheet sections with EVERLAST®ROOFSKIN
Figure 4: Elimination of cracks in the roof edge areas on flat concrete roofs with EVERLAST®ROOFSKIN.
Figure 5: Prevention of water leakage on corrugated asbestos cement roofs with EVERLAST®ROOFSKIN
Figure 6: Renewal of light dome joints on thermal roofs with EVERLAST®ROOFSKIN
Figure 7: Elimination of roof damage with foam filled steel sheet sections with EVERLAST®ROOFSKIN
Figure 8: Roof renewal on steel sheet sections with EVERLAST®ROOFSKIN
Figure 9: Long term roof protection with EVERLAST®ROOFSKIN
Figure 10: Bitumen sheet flatroof, sealed 50% with EVERLAST®ROOFSKIN
Figure 11:EVERLAST®ROOFSKIN forms an undestroyable bond to bitumen felt
Figure 12: Old damaged flat roof before applying EVERLAST®ROOFSKIN
Figure 13: Applying arylic fleece and SUPERPRIMER to roof (figure 12)
Figure 14: Flatroof (figure 12), sealed and restored with EVERLAST®ROOFSKIN
Figure 15: Thermally stressed roof-construction sealed with EVERLAST®ROOFSKIN
Figure 16: Thermally stressed flatroof-construction, sealed with EVERLAST®ROOFSKIN
Figure 17: Applying EVERLAST®ROOFSKIN as trowable paste to seal tube joints
Figure 18: Corners perfectly sealed with EVERLAST®ROOFSKIN-paste and fleece


1] DIN 7724
[2]"Fugen – Auslegung und Abdichtung"
Dr. Edvard B. Grunau, Siegfried Esser, Klaus Jürgen Jahn.
Institut für Baustofforschung 1992
EXPERT-VERLAG; ISBN 3-8169-0746-6.
3] "Handbuch Betonschutz durch Beschichtungen"
Hans Schuhmann u.a., 1992.
EXPERT-VERLAG; ISBN 3-8169-0577-3.