EP0286737A1 - Système de toit à membrane protégée pour aires de toit à trafic intense - Google Patents

Système de toit à membrane protégée pour aires de toit à trafic intense Download PDF

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Publication number
EP0286737A1
EP0286737A1 EP87303227A EP87303227A EP0286737A1 EP 0286737 A1 EP0286737 A1 EP 0286737A1 EP 87303227 A EP87303227 A EP 87303227A EP 87303227 A EP87303227 A EP 87303227A EP 0286737 A1 EP0286737 A1 EP 0286737A1
Authority
EP
European Patent Office
Prior art keywords
panels
ribs
foam
roofing system
channels
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
EP87303227A
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German (de)
English (en)
Inventor
Elizabeth Riley
Wayne E. Petersen.
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Dow Chemical Co
Original Assignee
Dow Chemical Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to US06/686,069 priority Critical patent/US4658554A/en
Application filed by Dow Chemical Co filed Critical Dow Chemical Co
Priority to EP87303227A priority patent/EP0286737A1/fr
Publication of EP0286737A1 publication Critical patent/EP0286737A1/fr
Ceased legal-status Critical Current

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04D—ROOF COVERINGS; SKY-LIGHTS; GUTTERS; ROOF-WORKING TOOLS
    • E04D11/00—Roof covering, as far as not restricted to features covered by only one of groups E04D1/00 - E04D9/00; Roof covering in ways not provided for by groups E04D1/00 - E04D9/00, e.g. built-up roofs, elevated load-supporting roof coverings
    • E04D11/02—Build-up roofs, i.e. consisting of two or more layers bonded together in situ, at least one of the layers being of watertight composition

Definitions

  • the waterproof membrane which may be bituminous built-­up sheet or which may be single sheet of waterproof material, is exposed to extreme temperature variations, as much as 210°F (99°C), to ultraviolet radiation, and to physical abrasion, all of which have a deleterious effect on the life of the roofing.
  • the polystyrene foam insulation placed over the waterproofing membrane protects the membrane from the effects of thermal cycling, temperature extremes, and physical abuse, thus reducing maintenance costs and prolonging the useful life of the entire roofing system. It has been found that the membrane so protected remains at stable temperatures below 100°F (38°C), even in hot summer weather. In fact, under normal conditions, the temperature of the membrane will remain within a range of 15 to 20°F -10°C to - 7°C of the building's inside temperature.
  • a polymeric fabric is installed over the foam to stabilize the system, and crushed stone or gravel ballast is applied to counteract the buoyancy of the insulation boards, to provide flammability resistance to the roof surface, and to shield the foam and fabric foam ultraviolet radiation.
  • crushed stone or gravel ballast is applied to counteract the buoyancy of the insulation boards, to provide flammability resistance to the roof surface, and to shield the foam and fabric foam ultraviolet radiation.
  • paving blocks may be used in place of stone, particularly if traffic is to be expected on the roof.
  • pedestals or stones are provided to space the paving blocks above the top of the foam insulation to permit adequate air circulation for drying of the roofing system on warm, dry days. It will also be appreciated that a base roof or deck of substantial strength must be provided to support the weight of such a roofing system.
  • the present invention provides an improved roofing system of the type in which a waterproof membrane is applied directly to the surface of a roof.
  • a waterproof membrane is applied directly to the surface of a roof.
  • Specific novel panels of rigid foam insulation having a plastic film laminated to the lower surface are then applied over the membrane; and paving blocks (generally made of concrete) are applied directly to the foam insulation without the necessity of pedestals or stones.
  • the novel insulation panels are made of of closed foam plastic and have elongated ribs arrayed on an upper surface of the panels, which ribs are coextensive with cut-out channels or valleys interposed between and demarking the ribs.
  • Another aspect of the present invention is that it provides a roofing system in which the upper surfaces of the foam plastic insulating blocks are ribbed, having alternating ribs and valleys, with the concrete paving blocks laid directly on the the ribbed surfaces of the foam blocks.
  • the roof system includes foam plastic panels which, subsequent to forming, are cut longitudinally to provide grooves or channels having bounding walls in which exposed crater-like recesses resulting from a cutting through of pockets in the foam panel are exposed, thus significantly increasing the panel surface area exposed and accelerating evaporation of moisture from the channel-delineating walls.
  • Foam plastic panels of the type finding utility in the roof system of the present invention may be produced using any preferred technique, including casting or by extrusion.
  • the panels are then physically modified by cutting grooves longitudinally across an upper surface zone of the panels to form alternating channels and ribs, the latter defining a discontinuous planar top surface of the panels.
  • Extruded panels of polystyrene foam insulation which have one surface with integrally formed, alternating ribs and grooves of equal width.
  • the polystyrene foam plastic material in the ribs is stiffer, stronger, and more resistant to deformation than the foam plastic material in the valleys, and throughout the body of the panels. It is believed that this strength increase was due to molecular orientation of the material brought about as it foamed during extrusion.
  • the rib array configuration in the foam plastic insulation panels is formed by cutting grooves or channels in extruded plastic sheet material, that is, by excising lineal sections from the panels, after extrusion.
  • An important feature of the insulation panels of the present invention is that in cutting the channels in the panels, an outer, essentially smooth, high-density skin is removed to present a surface which has been found to be much more conducive to releasing and dispersing of moisture accumulating on the outer upper surface of the panel.
  • each panel has an intact high density outer skin produced during extrusion and operative to deter invasive entry of water and moisture vapor into the panels, the lower surface of each panel also being bonded to a co-­continuous water-impervious film or sheet further to obviate intrusion of moisture into the body of the panel.
  • a related feature of the invention is that in cutting the plastic panels to form the channel and ribs array, hollow cells present within the body of the foam plastic panel are sliced through to established channel-­bounding walls having crater-like recesses in the exposed surface thereof, the walls presenting outwardly directed faces in which the area of exposed plastic material to the ambient environment and embraced in the recess-marked surface is significantly increased as compared with planar areas delineated by the perimetric borders of the channel-bounding walls.
  • a practical advantage derived from the increase in exposed surface area of the plastic panels, and realized by excising lineal sections from the panels to form channels therein, is that the resulting increase in surface area exposed to the ambient environment effects a corresponding increase in the effective rate of evaporation of moisture from the panels at the exposed walls of the channels formed in the panels.
  • the ribbed and grooved foam plastic insulation material having a plastic film laminated to the lower surface, is placed on top of a waterproof membrane, and concrete paving blocks are then laid directly on the ribs of the plastic panels and are then laid directly on the ribs of the plastic panels and are held gravitationally thereon.
  • a based roof or deck 10 is shown in Figure 1 as comprising a concrete slab. This slab would preferably be reinforced.
  • the roof deck could equally well be of wood construction, or of metal construction, and concrete simply has been chosen by way of illustration.
  • a waterproof membrane 12 overlies the roof deck 10. The membrane can be attached to the roof deck, or it can be loose.
  • the membrane can be a single sheet of polymeric material, liquid applied, modified bituminous sheet, or it can be an asphaltic built-up membrane.
  • Panels 14, preferably of extruded polystyrene foam, are laid on top of the membrane 12.
  • the foam panels include, on the top surface only, integral ribs 16 interspaced by grooves or valleys 18.
  • the ribs and the grooves in the illustrated embodiment are of equal lateral extent, being approximately one inch (2.5 cm) wide, and about 1/8 to 1/2 inch(0.3 to 1.3 cm)deep.
  • the upper surface zonal configuration of alternating ribs and grooves is produced by physically removing elongated sections of plastics material from the preformed, extruded panels. Suitable cutters may be used for this purpose.
  • An important advantage achieved by producing the channels (and ribs) by cutting the plastic panels 14 rather than by extrusion techniques is that in the cutting method of the present invention the operation has the effect of exposing crater-like recesses 20 as elements of the cut surfaces 22 bounding the grooves or channels 18.
  • the recesses 20 greatly increase the surface area exposed to the ambient environment and thus increase the rate of moisture dissipation from the panels, by evaporation at the walls 22 bounding the channels 18.
  • the cutting removes the smooth, high-density outer film formed upon extrusion and exposes a surface much more favorable to the dissipation of water and moisture.
  • the foam material at the rib sections 16 is stronger, more rigid, and more deformation resistant than is the material 24 beneath the grooves or valleys 18.
  • the polystyrene foam panels 14 are butted together along the longitudinal side edges 30 thereof. The ends 32 of the panels also are butted together.
  • the thickness dimension selected for the foam panels 14 is governed by the degree of insulating quality desired, but typically would be of the order of one to six inches (2.5 to 15 cm) thick.
  • the extruded polystyrene foam is of the enclosed cell variety to prevent moisture penetration.
  • the foam panels 14 by way of illustration are two feet by four feet (0.6 by 1.2M) , but the dimensions are not critical.
  • the lengths could be nine feet (2.7 m), or as much as sixteen feet (4.9 m), to perhaps as much as four feet (0.6 m).
  • Product size is not a critical factor, but handleability is. In windy areas the panels must not be so large as to be blown from a roof before the paving blocks are applied to hold them down.
  • a plastic film lamination 34 is secured to the lower surface of each foam insulation panel 14.
  • the film 34 may be adhesively secured to the foam, or may be heat bonded thereto.
  • the film 34 comprises LLDPE (linear low density polyethylene) (1.7 mils) plus EVA (ethylene-­vinyl acetate) (0.3 mil). Upon heating, the film is readily softened to fuse tenaciously to the foam. There may also be a certain degree of softening of the foam which enhances the adherence.
  • Paving blocks 36 are laid directly on top of the foam panels 14.
  • the paving blocks 36 conveniently are two feet (60 cm) square and two inches (5 cm) thick, and are not necessarily reinforced. Other dimensions can be used, such as eight inches (20 cm) by sixteen inches (40 cm); and reinforcement of the concrete can be used if desired.
  • the concrete blocks 36 are simply butted against one another, and preferably are laid so that the butted junctions do not coincide or register with the butted junctions of the underlying foam panels 14.
  • Figure 3 The exploded, fragmentary perspective view of Figure 3 is similar to Figure 1 and emphasizes the adherence of the film 24 to the underside of the panel 14, and the non-securement of other parts to one another, and shows the crater-like surface at walls bounding the cut-out channels 18.
  • the polystyrene foam panels 14 are of the closed cell variety and are reasonably waterproof. However, constant presence of water will cause some water penetration and associated loss of insulating qualities.
  • the film adhered or sealed to the bottom surface of the foam panels 14 inhibits water penetration of the foam.
  • the alternating ribs 16 and recesses or valleys 18 in the upper surface of the foam permit air circulation so that any rainwater or other moisture on top of the panels is dissipated on hot, dry days.
  • the increased surface provided by the crater-­like formations 20 in the cut channel surfaces 22 enhances the rate of water evaporation, as does the physical form of the exposed surfaces 22.
  • sun shining on the paving blocks will heat the air in the recesses and between the ribbed surfaces and the concrete paving blocks, thereby materially increasing the pressure of such air, thus augmenting the convection forces causing air to exit through the butted joints of the concrete paving blocks.
  • the accumulation of water over time is also minimized.
  • a film of water such as might lie between a flat topped foam insulation panel and a paver laid directly thereon would act as a vapor barrier to prevent drying out of the foam.
  • any film that might lie between the tops of the ribs and the concrete paving blocks is of minimal importance, since the sides 22 of the ribs 16 and the floors of the grooves or valleys 18 provide a large area free of such film for drying of the foam.
  • the exposed craters 20 further increase the area exposed, and otherwise augment the rate of moisture dispersion as compared with a skinned-­ over surface.
  • the ribbed construction also facilitates drying of the undersurfaces of the paving blocks. This is important for reasons including the further constant wetness of the undersurfaces of the paving blocks causes the bottom surfaces thereof to spall off in a few years.
  • pedestals are used for supporting the weight of the concrete paving blocks.
  • Pedestals occupy space that could otherwise be used for insulation, and hence do not add to the overall insulating qualities.
  • the pedestals are expensive, both in material cost and in labor of installation.
  • the costs of pedestals and the non-insulating area thereof are eliminated.
  • the present construction is not intended as a full substitute for plaza construction, but it can support rather considerable weight, and is fully suitable for foot traffic or for small vehicles for maintenance.
  • STYROFOAM® insulation for example, has a design compressive strength of about 25 pounds per square inch (170 kPa). If a safely factor of 5:1 is provided, then this reduces to 5 pounds per square inch.
  • a 24 by 24 inch (60 x 60 cm) paving block has approximately 600 square inches (0.37 M2) which covers a like area of the present plastic foam insulation, but divided by two due to the equal widths of the ribs and valleys. This provides 300 square inches ( 0.19 M2) of supporting area for a two foot by two foot (60 cm x 60 cm) paving block, which multiplied by the five pounds per square inch previously noted results in a total of 1500 pounds (680 Kg) that can be applied to each paving block with a 5:1 safety factor against permanent deformation of the supporting STYROFOAM® insulation due to creep and compressive fatigue.
  • each paving block can support 600 pounds (272 kg) with such foam plastic material.
  • rib width and spacing Exemplary dimensions have heretofore been given for the rib width and spacing. However, these dimensions can vary widely.
  • the ribs might be as little as 1/16th inch (0.16 cm) high, and the supporting area could be less than 50, percent i.e. the ribs could be narrower than the intervening valleys.
  • the present roofing system is highly desirable for construction of insulated roofs in which a certain amount of traffic or maintenance is anticipated.
  • the present roof construction also is beneficial for use in roof construction below radio and TV antenna towers in cold climates. Icicles dropped from such towers readily penetrate gravel-topped roof constructions, initially damaging the membrane and/or underlying insulation and leaving them vulnerable to possible further deterioration from water and ice.
  • the paving blocks used in the present construction are not penetrated by such icicles; no damage is caused by falling icicles.
  • the present roof system possesses all the advantages of prior "upside-down" insulated roof construction.
  • water absorption by the insulation is markedly reduced by the water-impervious film bonded to the lower surface of the insulation, and by the ribbed upper surface which allows drying of the insulation and the underside of the paving blocks on warm, dry days.
  • the rate at which water vaporizes from the channels is enhanced by the added surface provided by the cutting out of sections from the plastic panels, and by the physical form presented by the mechanically cut surfaces defining the channels.
  • the invention includes within its scope a roofing system of the type including a roof deck, and a plurality of panels of foam plastic insulation overlying said waterproof membrane, characterized by the combination of:

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  • Engineering & Computer Science (AREA)
  • Architecture (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Laminated Bodies (AREA)
EP87303227A 1984-12-24 1987-04-13 Système de toit à membrane protégée pour aires de toit à trafic intense Ceased EP0286737A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US06/686,069 US4658554A (en) 1984-12-24 1984-12-24 Protected membrane roof system for high traffic roof areas
EP87303227A EP0286737A1 (fr) 1987-04-13 1987-04-13 Système de toit à membrane protégée pour aires de toit à trafic intense

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP87303227A EP0286737A1 (fr) 1987-04-13 1987-04-13 Système de toit à membrane protégée pour aires de toit à trafic intense

Publications (1)

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EP0286737A1 true EP0286737A1 (fr) 1988-10-19

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EP87303227A Ceased EP0286737A1 (fr) 1984-12-24 1987-04-13 Système de toit à membrane protégée pour aires de toit à trafic intense

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2677062A1 (fr) * 1991-05-30 1992-12-04 Induplast Sa Panneau support de revetement a usage pietonnier.
WO2007137592A1 (fr) * 2006-05-30 2007-12-06 Briceno Matute Alberto Arturo Microbéton vibropressé dans un coffrage synthétique pour la production de panneaux-couches-formes

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1509126A1 (de) * 1963-11-11 1969-05-29 Alois Petri Dachisolierplatte
DE2041990A1 (de) * 1970-08-25 1972-03-02 Isopor Kunststoff Gmbh Waermedaemmender,aus Platten od.dgl. aus Hartschaumkunststoff bestehender Belag fuer Flachdaecher
US4064301A (en) * 1977-02-14 1977-12-20 Day Star Foam Company Floral base
DE2901187A1 (de) * 1979-01-13 1980-07-24 Mizell Emerson H Isolierprofil mit t-foermigem querschnitt und dampfsperre
US4492064A (en) * 1981-12-11 1985-01-08 The B. F. Goodrich Company Insulated roof construction
WO1986001245A1 (fr) * 1984-08-10 1986-02-27 The Dow Chemical Company Systeme de toiture legere

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1509126A1 (de) * 1963-11-11 1969-05-29 Alois Petri Dachisolierplatte
DE2041990A1 (de) * 1970-08-25 1972-03-02 Isopor Kunststoff Gmbh Waermedaemmender,aus Platten od.dgl. aus Hartschaumkunststoff bestehender Belag fuer Flachdaecher
US4064301A (en) * 1977-02-14 1977-12-20 Day Star Foam Company Floral base
DE2901187A1 (de) * 1979-01-13 1980-07-24 Mizell Emerson H Isolierprofil mit t-foermigem querschnitt und dampfsperre
US4492064A (en) * 1981-12-11 1985-01-08 The B. F. Goodrich Company Insulated roof construction
WO1986001245A1 (fr) * 1984-08-10 1986-02-27 The Dow Chemical Company Systeme de toiture legere

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2677062A1 (fr) * 1991-05-30 1992-12-04 Induplast Sa Panneau support de revetement a usage pietonnier.
WO2007137592A1 (fr) * 2006-05-30 2007-12-06 Briceno Matute Alberto Arturo Microbéton vibropressé dans un coffrage synthétique pour la production de panneaux-couches-formes

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