Abstract:
Disclosed herein is a hail resistant roof system having a roof deck. An insulation layer is supported by the roof deck. An energy absorbing layer supported by the insulation layer and a waterproof membrane loose laid over the energy absorbing layer. A wind blown debris resistant roof system is disclosed that includes a roof deck with a secondary waterproof membrane disposed over the deck. A layer of stiff material is attached to the roof deck and a primary waterproofing membrane is supported by the stiff material. Further, a roof insulation and waterproofing construction upwardly adjacent the waterproofing membrane. Also disclosed herein is a hail resistant roof system. The system includes a roof deck with a secondary waterproofing membrane. An insulation layer is supported by the roof deck. An energy absorbing layer is supported by the insulation layer and a primary waterproof membrane is loose laid over the energy absorbing layer.

Description:
BACKGROUND 
     Large roof structures which are typically more common in the commercial industry, but not exclusive thereto, provide a very large surface area which necessarily increases the possibility of impact and potential damage by hail or wind blown debris in the event of more unfavorable weather conditions. Roofing companies and roof owners are both, understandably, quite concerned about the potential damage of hail and wind blown debris since if a roof system is catastrophically failed by either one of or both of those implements, substantial damage is incurred. The damage occurs in the roof structure itself, replacement of which is not inexpensive and beyond that can be incurred for structures, equipment or inventory stored within the building. Clearly, this kind of damage is associated with potentially massive cost. Art work or sensitive equipment are but two possible items contained within a building which would be utterly destroyed by any significant amount of water being introduced thereto. For these reasons the industry has long attempted to build roof structures capable of handling such aggressors as hail and wind blown debris. One system which does have some ability to ward off hail and wind blown debris employs waterproof structures and a gravel top layer. Historically such structures were being built in many venues, however, more recently the industry has moved toward membrane type roof systems without gravel topping structures for several reasons which are not germane hereto. This has made the risk from hail and wind blown debris more of a concern. To date, however, there are no effective solutions for the problem. 
     SUMMARY 
     Disclosed herein is a hail resistant roof system having a roof deck. An insulation layer is supported by the roof deck. An energy absorbing layer supported by the insulation layer and a waterproof membrane loose laid over the energy absorbing layer. 
     A wind blown debris resistant roof system is disclosed that includes a roof deck with a secondary waterproof membrane disposed over the deck. If the roof deck is weak and cannot resist wind blown debris itself a layer of stiff material is also attached to the roof deck before the secondary waterproofing membrane is installed. Further, a roof insulation energy adsorbing layer and primary waterproofing construction is installed over the secondary waterproofing membrane. 
     Also disclosed herein is a hail resistant roof system. The system includes a roof deck. An insulation layer is supported by the roof deck. An energy absorbing layer is supported by the insulation layer and a primary waterproof membrane is loose laid over the energy absorbing layer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       Referring to the drawings wherein like elements are numbered alike in the several Figures: 
         FIG. 1  is a schematic representation of a first embodiment of a hail resistant roof assembly; 
         FIG. 2  is a schematic cross-sectional view of an energy absorber/dissipater at a first stage of breaking; 
         FIG. 3  is a schematic cross-sectional view of an energy absorber/dissipater at a second stage of breaking; 
         FIG. 4  is a schematic cross-sectional view of an energy absorber/dissipater at a third stage of breaking; 
         FIG. 5  is similar to the  FIG. 1  embodiment however it has been modified to also be a wind blown debris resistant roof assembly; 
         FIG. 6  is an alternate embodiment of the wind blown debris resistant roof assembly; 
         FIG. 7  is an alternate embodiment of a hail resistant roof assembly; and 
         FIG. 8  is an alternate embodiment of a hail resistant roof assembly. 
     
    
    
     DETAILED DESCRIPTION 
     It will be understood by one of ordinary skill in the art that a hail resistant roof assembly and a wind blown debris resistant roof assembly are related in that the top layer of these assemblies is configured to absorb an impact from a solid object. The roof embodiments that are considered to be wind blown debris resistant roof assemblies further include an additional waterproofing membrane in a protected location in a roof construction. The distinction is that while the hail resistant roof assemblies are intended to absorb impact there are some impacts sustainable from wind blown debris that will be far in excess of the capability of the hail resistant roof assembly to prevent the waterproofing membrane from rupturing. In order to avoid the deleterious effects of water coming through the roof membrane into a building, an additional membrane is provided to prevent water infiltration to the building. Where significantly large wind blown debris is not anticipated, a hail resistant roof assembly will be sufficient. 
     Referring to  FIG. 1 , the general concept of the hail resistant roof assembly is ascertainable from review of the first embodiment thereof. In order to more clearly illustrate the roof assembly, walls  10  and roof deck  12  provide an indication of the basic structure. Above the roof deck  12  is sufficient material to make the roof deck monolithic. This may be either strips of membrane material  14  as shown, a polyurethane foam or other material sufficiently impermeable to create an air sealed deck or substrate surface. It is noted that inherently air sealed decks such as concrete (poured-in-place) are also contemplated. Once the deck or substrate above the deck has been sufficiently air sealed, an insulation layer  16  is loose laid thereupon. The insulation can also be adhered entirely or spot adhered as illustrated at  18  to the air sealed roof deck  12 . Adherence may be effected by glue or other substance or configuration that does not render the air seal configuration ineffective. Mechanical fasteners are only employed if they too are sealed so the substrate air seal is not lost. The insulation is a rigid roof insulation having a minimum one pound density 1 ½ inch thickness in expanded polystyrene or polyisocyanurate. Above and supported by the insulation  16  is an impact absorber dissipater  20 . In one embodiment absorber/dissipater  20  is gypsum board. The board in one embodiment is about ½″ thick. In the case of gypsum board, energy absorption/dissipation occurs in the form of a successive breaking of the board which is illustrated in drawings  FIGS. 2 ,  3  and  4  in sequence. Breakage may be generally concentric or spiral for individual locations. During the rapid stepwise breakage following an impact from a hail stone or other similar object, kinetic energy is absorbed. More specifically, some of the total kinetic energy of the object is absorbed with each breakage until sufficient kinetic energy has been absorbed that the hailstone can no longer break the board. The stone has thus been effectively stopped. Gypsum board is particularly effective because small sections break at the break site so that the roof structure “bounces back” to some extent. Although three breakages are illustrated in  FIGS. 2-4  this is but one example. More or fewer breakages are possible and correspond to the amount of energy in the solid object. As illustrated,  FIG. 2  shows one breakage  42 ;  FIG. 3  shows two breakages  42  and  44 ; and  FIG. 4  shows three breakages  42 ,  44  and  46 . As illustrated sequentially in  FIGS. 2-4 , the object  40  is protruding farther into absorber/dissipater  20 . 
     Referring back to  FIG. 1 , a waterproofing membrane  22  is loose laid on absorber/dissipater  20 . Further, in one embodiment a wrinkle  24  is intentionally created in membrane  22  to keep additional membrane material “in reserve”. The excess membrane in wrinkle  24  provides material that can be “pulled” by object  40  into a depression created thereby preventing rupture of membrane  22 . In combination with wrinkle  24  or in another embodiment not having wrinkle  24 , a fold  26  is created for the same purpose as wrinkle  24 . In both cases, the provision prevents membrane  22  being held taught. If membrane  22  is taught, it is more likely to rupture because incident to the impact, a depression will be formed in the roof assembly. In the event membrane  22  cannot move into the depression, it will be caused to stretch into the depression, and rapidly, making rupture more likely. The foregoing is illustrated in  FIGS. 2-4  wherein the membrane material may be pulled into a depression  48  formed by object  40 . 
     Referring to fold  26 , it is noted that the fold is located beneath inverted “L” metal  28  and that metal  28  is configured, including attachment to the roof deck  12  if any, not to inhibit the movement of membrane  22  from fold  26 . In the event metal  28  is adhered to membrane  22  it will be with an adhesive which can be defeated by an anticipated magnitude of pull on membrane  22  as is generated by a hypothetical object  40 . In one embodiment, the adhesive is butyl rubber. 
     Referring now to  FIG. 5 , an alternate embodiment directed to wind blown debris resistance as well as hail resistance is illustrated. Several of the elements of  FIG. 5  are identical to those discussed with respect to  FIG. 1 . These elements are identified with identical numerals to  FIG. 1 . The distinction, as will be readily appreciated from perusal of  FIGS. 1 and 5  simultaneously. 
     Atop roof deck  12  is a membrane  50  which in one embodiment is adhered to deck  12 . As illustrated the adhesive  52  extends to all locations under membrane  50 . It is also possible to spot adhere membrane  50  to deck  12  but is still desirable to maintain the placement of adhesive on deck joints as in  FIG. 1  to prevent air from migrating to locations under membrane  50  from within the building structure weather sealed by the roof depicted. In this embodiment, membrane  50  provides additional water proofing for the roof in that in the event that wind blown debris impacts the membrane  22  with energy sufficient to rupture membrane  22 , membrane  50  will prevent interior building damage until the roof system can be repaired. The system of  FIG. 5  works identically to that of  FIG. 1  for smaller impacts but provides the additional protective margin of membrane  50  for eventualities rupturing membrane  22 . 
     Referring to  FIG. 6 , an alternate windblown debris resistant roof assembly with a deck that could be impacted or penetrated by flying debris and an additional strengthening board of plywood, OSB wafer, gypsum or similar is added to the deck is illustrated wherein the assembly is configured for a building  10  having a parapet  60 . Membrane  50  is brought up parapet  60  to a level above the “field” of membrane  22  such that membrane  22  is securable and air sealable to membrane  50  by adhesive  62 . Adhesive  62 , and adhesive  64  at an opposite roof edge maintain an air sealed roof assembly between membrane  22  and membrane  50 . It may additionally be desirable to mechanically attach membranes  50  and  22  to parapet  60  with fastener  66  with appropriate sealing compound such as butyl rubber. In other respects the embodiment is similar to the foregoing. 
     Referring to  FIG. 7 , a pitched roof assembly is illustrated in a configuration allowing for hail resistance. Building  70  includes parapet  72  and a roof deck  74 . Above roof deck  74  is an angled layer of insulation  76 . Above the insulation  76  is an absorption/dissipation layer  78 , which in one embodiment is gypsum board. A membrane  22  is lose laid thereover except proximate the parapet  72  where adhesive  80  is placed to maintain membrane  22  in a desirable position during normal operation and configured to fail under shear load in the event of a hailstone impact to allow fold  82  to be “pulled” out across the roof assembly. This is similar to foregoing embodiments and does not require further detailed discussion here. It is noted that in this embodiment adhesive  80  is also placed between layers of the membrane  22 . After fold  82  membrane continues onto parapet  72  and is adhesively affixed to membrane section  84 , which itself is adhesively affixed to parapet  72  and to deck  74  in an air sealed manner. In one embodiment, membrane  22  and section  84  are also mechanically affixed to parapet  72  with fastener  86 . In this illustration a further water proofing member  88 , which may be membrane or metallic, or other waterproofing, environment-resisting material is adhesively affixed on the top of parapet  72  and extends down beyond fastener  86  to shed water over the fastener helping to avoid leaks. 
     Referring now to  FIG. 8 , another alternate embodiment is illustrated. In this embodiment, the structural components of the building are identical and are thus labeled identically. The roof assembly is distinct however. In this embodiment, angled insulation is used as in a foregoing embodiment, however the insulation is specifically configured to receive a fold of membrane  22 . Insulation perimeter section  100  is undercut at  102  to leave space for a mechanical fastener  104  fastening a perimetral edge of roof membrane  22  and is installed after the installation of the field section of the roof assembly including insulation  106 , absorption/dissipater board  108  and membrane  22 . 
     As it appears to one of ordinary skill in the art from a review of  FIG. 8 , membrane  22  is loose laid over board  108  and insulation  106  similar to foregoing embodiments. At a perimeter edge of field section  110 . Membrane  22  is folded on itself as  112  before being fastened to deck  74  with fastener  104  and adhesive  114 . Subsequent to such securement, insulation  100  is installed over termination  104  and weighted in place with board  116  insulation  100  and a portion as illustrated of membrane  22  (and sub assembly). This board  116  may also be gypsum board. Finally, an additional waterproofing material, being membrane or metal or equivalent is adhered to membrane  22  at  118  and to board  116  parapet  72  with adhesive  120 . It will be appreciated from the foregoing discussion that  118  is an adhesive designed to fail under shear such that fold material at  112  can be pulled out onto the roof field in the event of age related shrinkage and/or a hail stone impact to reduce tensile force on the membrane thereby averting a membrane rupture. 
     While preferred embodiments have been shown and described, modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation.