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You are an expert at summarizing long articles. Proceed to summarize the following text: 
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority under 35 U.S.C. § 119(e) to copending provisional application Ser. No. 60/908,073 filed Mar. 26, 2007, Ser. No. 60/909,051 filed Mar. 30, 2007, and Ser. No. 60/910,138 filed Apr. 4, 2007. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates to construction materials and systems, and in particular to furring materials used to construct walls, ceilings, flooring and roofing of buildings. The invention provides a significant improvement over conventional furring materials that can trap moisture behind wall panels and causing mold and mildew growth and rot. 
       SUMMARY OF THE INVENTION 
       [0003]    The present invention provides a furring strip system with built-in alignment and airspace between interior and exterior walls for ventilation and rainscreen protection. A wall grid system speeds installation. 
         [0004]    The furring strip system has application to installation of drywall panels, deck applications, and floor applications. The system allows release of moisture from wood and wood plastic composite (WPC) decking via a space between boards. The invention further has application to roof installations with cross bars as well as different types of roofing, and ceiling applications. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]      FIG. 1  shows a front view of a metal furring strip according to the invention; 
           [0006]      FIG. 2  illustrates cross-sectional views of various different shapes of a metal furring strip in accordance with the invention; 
           [0007]      FIG. 3  shows a furring strip grid in accordance with another aspect of the invention; 
           [0008]      FIG. 4  shows the use of a horizontal furring strip in accordance with the invention, for adjustment of alignment with variably spaced wall studs; 
           [0009]      FIG. 5  illustrates a panel hanging tool in accordance with the invention for use with the furring system of the invention; 
           [0010]      FIG. 6  illustrates an example of the hanging of a wall panel using the furring system of the invention; 
           [0011]      FIG. 7  shows side views of different configurations of hanging tool in accordance with the invention; 
           [0012]      FIG. 8  shows an example of attachment of the panel hanging tool to the furring strip of the invention; 
           [0013]      FIG. 9  shows an example of a leg that catches the underside of a furring strip of the invention for attachment of the hanging tool; 
           [0014]      FIG. 10  shows the use of hanging tool cross slots for vertical applications; 
           [0015]      FIG. 11  shows an example of a vertical panel hanging application; 
           [0016]      FIG. 12  shows examples of various shape and size configurations of furring strip slots in accordance with the invention; 
           [0017]      FIG. 13  shows another example of a furring strip grid system in accordance with the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    As shown in  FIG. 1 , furring strips  10  are preferably made from steel blanks, with chamfered holes  12  for screw leveling flush to the strip surface. The holes may be manufactured to different increments such as 12″, 8″ etc.  FIG. 2  shows examples of various cross-sectional shapes for the furring strips  10 , which allow the installation of various types of drywall, boards, panels, siding, etc. The furring strip  10  may have hemmed legs  22  for added strength, and can be made to different depths as well as different lengths. The steel strips can be used as a fireblock in the horizontal direction, and a drip edge may be added for drainage. The hollow back allows only a small amount of the surface to which the furring strip is being attached to be contacted by the strip. This allows for the maximum amount of air flow and drainage on a substrate. 
         [0019]    Preferably, the furring strip  10  is a hollow vented strip made from a durable material such as steel. It can be used for all types of furring. Among its advantages, the furring strip system according to the invention can be made to custom lengths, will not burn in the event of a fire, and can be made with tolerance consistent to 1/10,000 of an inch. The furring strip is vented so that it allows moisture to flow down the steel furring strip and vent an entire wall. This feature is a significant improvement over a conventional solid furring strip such as wood furring strips that can trap moisture in walls, roofs, and floors, causing rotting. The furring strip also can be vinyl-coated to act as a thermal break or barrier for the metal to reduce heat and cold conduction caused by metal such as steel. 
         [0020]    The metal furring strip also can utilize a foam or plastic block to create a larger airspace behind wall panels. These blocks can snap into the back of the metal furring strip. This also creates a thermal break for the metal. The metal furring strip  10  can preferably be manufactured from G-90 Galvanized steel to reduce the possibility of rusting. The furring strip system alternately can be manufactured from vinyl, fiberglass, aluminum, and other composite materials. 
         [0021]    The furring strip can have clips and screw holes pre-punched to attach and to receive different types of ceiling panels, wall panels, flooring, exterior siding panels, decking panels, roofing panels, overhang panels etc. 
         [0022]      FIG. 3  illustrates a pre-fabricated furring strip grid system  30  using cross-members  31  to allow fast installation of furring strips  10  all at one time, according to another aspect of the invention. The furring system automatically spaces itself on 6″, 8″, 10″ 12″, 16″ and 24″ spacing increments for spacing automatically by applying cross members  31 . As shown in  FIG. 4 , the furring strips  10  can be adjusted horizontally along the cross-members  31  for studs that are variably spaced. The furring strips  10  can be attached to the cross-members  31  by various attachment mechanisms such as clamps with wing screws, magnetic clamps, etc. 
         [0023]      FIG. 5  shows a panel hanging tool  50  in accordance with the invention for use with the metal furring strip system. The tool  50  is inserted into slots, holes, or openings in the furring strip, and holds wall or ceiling panels in place until final attachment to the steel furring strip is made. This feature enables one person installation The tool  50  has a screw clamp  54  for adjustably attaching to the furring strip, as shown in detail in  FIG. 8 . Use of the screw clamp  54  eliminates the need for any punches on the furring strip. The tool  50  also has a number of slots  52  for insertion of clips to hold wall panels for attachment to the furring strips. This is shown in  FIG. 6 , where a panel  60  is hung between two furring strips  10  using hanging tools  50 . 
         [0024]    As shown in  FIG. 7 , the tool  50  may have downward facing hooks  72  and/or upward facing hooks  74  for accommodating various types of tongue-and-groove panels for walls, floors, ceilings, roofs, siding, log siding, overhangs, decks, etc., and an additional projection  76  located in the middle of the tool for accommodating double panels. 
         [0025]      FIG. 9  shows an example of a furring strip  10  with cross-slots  102  for vertical panel applications, as shown in  FIG. 11 .  FIG. 11  illustrates a vertical panel  60  being hung on a single furring strip  10  using the hanging tool  50 . 
         [0026]    As shown in  FIG. 12 , the furring strips may have smaller slots to increase strength. The slots, holes, or apertures can be set at different increments and can have various sizes and shapes to accommodate various different applications. 
         [0027]      FIG. 13  shows a second example of a grid system for strips  10  being attached to cross-members  31 , with screws being used to attach the horizontal bars through the slots or with metal tapping screws. 
         [0028]      FIG. 14  shows an example of an installed panel system  140  wherein panels  60  are attached to furring strips  10  via concealed hook fasteners  141  and  142 . Different hook dimensions can be provided to fit all sizes of panels. 
         [0029]    As shown in  FIG. 15 , the furring system of the invention eliminates attachment of panels through the face of the panels, by using j-shaped hooks  142 , giving a concealed attachment and cleaner look to the installed panels. A special starter strip hook  151  can be provided at the bottom of the strip  10 . As shown in  FIG. 15 , the panel  60  is first inserted into the starter hook  151  and then rotated into place under the hook  142 . The next panel  61  then is installed over the top edge of the panel  60 , resting on hook  142 .  FIG. 16  shows a configuration wherein panel  61  is fitted under a top hook  171 . 
         [0030]      FIG. 17  shows a starter strip  191  for a foam back vinyl siding design clip that sticks into the back of a vinyl siding panel  192 .  FIG. 18  shows an example of tongue-and-groove attachment technology, wherein hooks  181  insert into a channel or clip  182  fastened to the back of a tongue-and-groove panel  60  for attachment of the panel to the furring strip  10 . The small channel  182  either can be glued onto the back of the panel, or pop riveted or screwed onto a wood siding fiber cement panel, roofing panel, interior wall covering panel, decking panel, aluminum panel, ceiling panel, or floor panel.

Summary:
A furring strip system with built-in alignment and airspace between interior and exterior walls for ventilation and rainscreen protection. A wall grid system speeds installation. The furring strip system has application to installation of drywall panels, deck applications, and floor applications. The system allows release of moisture from wood and wood plastic composite (WPC) decking via a space between boards. The invention further has application to roof installations with cross bars as well as different types of roofing, and ceiling applications.