Patent Publication Number: US-10774562-B1

Title: Railing anchor

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to an improvement in mounts for railings, especially on balconies and more especially on balconies made with wood substrates and having lightweight concrete tread surfaces. 
     Multifamily buildings often have balconies and, where code permits, are often framed with wood. The supports for the balconies extend outward from outer building walls and are often made of wood such as 2×10&#39;s. The supports have a wooden deck (particularly plywood or chipboard) topped with a lightweight concrete. 
     The balconies also need to have railings to protect occupants of the finished dwelling. Aluminum is a preferred railing material for durability and light weight. The railings need to be strong enough to prevent impacts from dislodging the railings from the balcony and, in the balconies discussed above have conventionally been anchored to the wooden support and deck in order to have a strong base. 
     This form of construction has been found to be cost-effective. An important precaution, though, is that the wooden support and deck must be shielded from water ingress. Penetrating water causes early failure and needs to be avoided. 
     Usually, a shield to prevent water from getting to the wood is installed, and conventional railing anchors with affixed posts are mounted to the deck so they extend upward as what the trade calls a “missile.” Then the concrete is poured. However the missile acts as a large protuberance that can cause its own problems. Workers building the dwelling often use the doorway to the balcony to move construction materials into the building and to remove debris. During those movements, the materials or the worker may collide with the missile, dislodging it and damaging the water-tight seal. Repairing such damage is quite expensive. Thus, there is a need in the art for an improved railing support for a wooden balcony having a lightweight concrete tread surface. 
     SUMMARY OF THE INVENTION 
     The present invention fulfills one or more of these needs in the art by providing a railing anchor arrangement that includes a wooden support and a wooden deck on the wooden support. A first metal plate on the wooden deck has threaded holes. A moisture barrier covers the wooden deck and seals to the first metal plate. The moisture barrier can be a waterproof membrane. At least one lag bolt extends downward from the metal plate through the wooden deck and is secured in the wooden support to secure the metal plate onto the wooden deck and the wooden support. Threaded studs extend upward from the holes in the first metal plate. Concrete can be poured on the moisture barrier to make a tread surface and the first metal plate, and a second metal plate with a post for a railing can be mounted atop the concrete by aligning holes in the second metal plate with the studs. 
     In one embodiment the first metal plate has six holes, with two lag bolts occupying two of the holes and four threaded studs occupying four of the holes. The studs may have nuts above and below the second metal plate to hold the second metal plate spaced above the first metal plate. A shield preferably surrounds each stud between the metal plates to prevent contact of the concrete with the threads of the studs. The shield may be a polyvinyl chloride sleeve. 
     Preferably, the first metal plate and studs are steel and the post for a railing is aluminum. Places where a steel part is adjacent an aluminum part are provided with an isolation barrier, to prevent galvanic action between the different metals. 
     The threaded studs that extend upward from the holes in the first metal plate are preferably mounted by mating stud threads to threads in the holes of first metal plate with a thread locker adhesive where the studs mate with the first metal plate. 
     Typically, the concrete is a lightweight concrete. Preferably, the second metal plate is separated from the concrete by an isolation barrier. 
     The invention can also be considered as a method of installing a railing on a surface having a wooden support and a wooden deck topped with a moisture barrier and a lightweight concrete surface. The method includes mounting a steel plate on the wooden deck by driving lag bolts downward through holes in the steel plate, through the wooden deck and into the wooden support, the steel plate having threaded studs standing upright from the steel plate. The method also includes applying a moisture barrier to the wooden deck and sealing the moisture barrier against at least edges of the steel plate. Then a lightweight concrete is poured on the moisture barrier and the steel plate to a desired depth, leaving tops of the threaded studs exposed above a top surface of the lightweight concrete. The lightweight concrete is allowed to cure. The method includes subsequently mounting an aluminum railing post on the concrete by fitting an aluminum plate having an affixed aluminum railing post over the threaded studs and tightening nuts onto the threaded studs. 
     Applying a moisture barrier may be accomplished by adhering a waterproof membrane onto the wooden deck. The steel plate is mounted on a part of the waterproof membrane and then covered with a mastic sealant to prevent water ingress through openings caused by the mounting of the steel plate. The method may include moving materials across the concrete into an adjacent building once the lightweight concrete has cured and before mounting the aluminum railing post 
     The method may include installing a temporary railing post over the studs once the lightweight concrete has cured and before mounting the aluminum railing post 
     The invention can also be considered as a railing anchor for a balcony that has a wooden support, a plywood deck on the wooden support and a moisture barrier covering the plywood deck. The railing anchor includes a steel plate adapted to be mounted on the plywood deck and having four threaded holes and suitable to be mounted on a moisture barrier. Four steel threaded studs extend upward from four of the holes in the steel plate and are mounted to the steel plate by mating stud threads to threads in the holes of steel plate with a thread locker adhesive where the studs mate with the steel plate. Two other holes in the steel plate are configured to receive lag bolts that can extend downward from the steel plate through the plywood deck and be secured in the wooden support to secure the steel plate onto the plywood deck and the wooden support. The holes of the steel plate are preferably arranged in two lines of three holes each. The steel plate may have a centerline marked between the two lines of three holes. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be better understood by a reading of the Detailed Description of the Examples of the Invention along with a review of the drawings, in which: 
         FIG. 1  is a cutaway perspective view of a balcony having an anchor in accordance with an embodiment of the invention; 
         FIG. 2  is a sectional view of the embodiment of  FIG. 1  taken along lines  2 - 2  and looking in the direction of the arrows; 
         FIG. 3  is a sectional view of the embodiment of  FIG. 1  taken along lines  3 - 3  and looking in the direction of the arrows; 
         FIG. 4  is a sectional view of the steel plate; 
         FIG. 5  is a top view of the steel plate; 
         FIG. 6  is a top view of the aluminum plate and post; and 
         FIG. 7  is sectional view of the aluminum plate and post. 
     
    
    
     DETAILED DESCRIPTION OF EXAMPLES OF THE INVENTION 
     As seen in  FIGS. 1-3 , a railing anchor arrangement and has a wooden support  12  and a plywood deck  14  on the wooden support. The wooden support or wooden blocking is quite substantial, typically several 2×10&#39;s arranged to form a cantilever support from the main building wall (not shown). A moisture barrier  16  (such as a waterproof membrane) covers the plywood deck. A steel plate  22  is mounted on the membrane on the plywood deck. The steel plate  22  has two unthreaded holes  52  and four threaded holes (see  FIG. 5 ). Two steel lag bolts  20  extend downward from the two unthreaded holes  52  in the steel plate through the plywood deck and into the wooden support  12 , for instance protruding into non-threaded clearance holes. Four steel threaded studs  24  extend upward from the four threaded holes in the steel plate. The stud shanks can be ⅜ inch in diameter. The holes  52  could be threaded, but that is not necessary. A mastic sealant  17  is applied to the steel plate  22  to seal paths for moisture that may have been formed to the deck  14  by the installation of the steel plate. 
     A lightweight concrete  18  can be poured on the moisture barrier  16  and the steel plate  22  to make a tread surface. A form  40  around the perimeter of the deck contains the wet concrete and determines its height. Once the concrete cures, an aluminum plate  26  with a post  28  for a railing can be mounted atop the lightweight concrete by aligning holes  42  (shown in  FIGS. 6 and 7 ) in the aluminum plate with the studs  24 . 
     The steel plate  22  is seen in more detail in  FIGS. 4 and 5 . A suitable size for the plate is four inches square with a minimum thickness of about ⅝ inch. The holes for the lag bolts and the studs are arranged in two rows of three, but other arrangements may be suitable. The placement of the holes for the studs is such that the studs will align with holes in the aluminum plate  26 . The plate  22  may be marked with a centerline between the two rows of holes to aid in placement of the plate on the deck. 
     The studs  24  may have nuts  34  above and below  32  the aluminum plate to hold the aluminum plate spaced above the steel plate. A shield such as a polyvinyl chloride sleeve or tube  25  preferably surrounds each stud between the steel and aluminum plates. The shield prevents contact of the concrete with the threads of the studs. Places  44  where a steel part is adjacent an aluminum part are provided with an isolation barrier, to prevent galvanic action between the different metals. The aluminum plate  26  is separated from the concrete by an isolation barrier  27 . 
     The railing anchor arrangement can be mounted in a step-wise fashion. Once the wooden support  12  and deck  14  are in place, the waterproof membrane  16  can be installed on the deck  14 . The first metal plate  22  can be placed on the membrane  16  on the deck with the centerline parallel with the expected railing direction. The studs  24  are typically already installed on the metal plate  22  with a thread locker adhesive at a factory before the plate is mounted to the deck, but the studs could be installed on the plate on the jobsite. 
     On the jobsite, the lag bolts are installed to secure the plate  22  to the deck. Then the mastic  17  is applied to the metal plate  22  and a waterproof seal is made between the barrier  16  and the plate  22 . 
     The lightweight concrete can then be poured. The form  40  around the perimeter of the deck contains the wet concrete and determines its height. The only portion of the anchor extending above the top of the concrete is the top portion of the studs  24 , since the second plate  26  and its post  28  are added later. In the meantime, workers can access the interior of the building through the door to the balcony to move materials into the building and to remove debris from the building. The small area of the top portion of the studs thus is a small target that is more likely to be avoided by transit of materials in and out of the building than when the posts are missiles. In addition, in the event of a collision with transiting materials or workers, since the studs are smaller than the missiles of the prior art there is a reduced lever arm to dislodge the stud and/or disturb the waterproof barrier. In the event the stud is bent or the barrier is disturbed, the stud can be removed and replaced and the waterproof barrier can be repaired with mastic. 
     If desired, a temporary railing post can be mounted on the concrete and secured to the studs, such as to comply with worker safety codes that require a temporary guardrail. The railing post can have brackets to removably hold horizontal railings, such as 2×4&#39;s. The 2×4&#39;s can be moved out of the way when the balcony doorway is being used for transiting materials or workers. 
     Preferably, the railing that is installed complies with terms on building codes. The railing, post and second plate can be made if various materials, preferably aluminum or steel. 
     Certain modifications and improvements will occur to those skilled in the art upon reading the foregoing description. It should be understood that all such modifications and improvements have been omitted for the sake of conciseness and readability, but are properly within the scope of the following claims.