teqniqal
Well-Known Member
Re: Resurfacing Stage Floor or new?
1/4" thick ANSI Class 3 hardboard can't be bought for '20 dollars', nor is it a '90 dollar' replacement - it about 1/2 way between the two. The point of installing a quality hardboard surface (as opposed to a '20 dollar' hardboard surface) is that it may not need to be replaced for 10-20 years (or more), and when it does, you only replace the top sacrificial layer, not the plywood sub-floor (unless there is some significant rot or structural damage issue).
As to the various types of fastening methods, the use of countersunk deck screws at either a 4 x 7 pattern (~16" o.c.) or a 5 x 9 pattern (~12" o.c.) is fairly common. If you place a round paper 'dot' (like the stickers you get at an office supply store) over each screw before you paint the deck it makes it easier to get a screwdriver bit back in the screw slots in the future.
Pre-drilling ANSI Class 3 hardboard, or Plyron can be done by most automated cabinetry shops equipped with CNC wood tools. They crank-out hundreds of complex wood cabinet parts per day, so a rectangular pattern of precisely placed holes to a specified depth is simple and worth whatever price they ask. The precise depth allows each screw head to sit exactly flush to the floor surface, not depressed, not protruding.
A more recent invention by 3M company may make the screw-down approach less common. They have a super-heavy-duty double-sided tape called 'Hurricane Tape' (Type VHB) that is used to secure metal siding panels to the exterior of buildings. It is thin, not like double-sided foam tape, and available in several widths. If you use some strips of this to lay down each sheet onto the sub-flooring, it can later be torn-loose by pulling a piano wire between the sheets to cut the bond. It's not cheap, but it makes a blemish-free floor and it significantly reduces the labor cost of drilling and screwing a bajillion holes.
Not mentioned in this thread is fire-retardancy requirement defined in many building codes. Some are defined in a performance related manner (xx hours fire rating) while others are prescriptive to the construction (2 layers of plywood with a top layer of XX). If you replace your floor with fire-retardant rated material (like Sierra Pine's Medite FR), you can satisfy the fire retardant requirement quite easily and may not need to mix fire retardant into the stage deck paint. Replacing your floor would, under most codes, be considered major constructions and may require a permit, which in-turn, requires that the floor assembly meet current construction codes.
'lwinters360' mentioned that the existing floor might be a "pine / plywood / sleeper / concrete" layering. The ability for a floor to provide some cushioning for performers (particularly dancers but certainly not limited to them) should not be overlooked. Consideration should be made for installing a layer of shock-absorbing rubber between the concrete and the sleepers (which may require reducing the thickness of the sleepers).
Also not mentioned was the in-fill in the floor void between the sleepers. Many older buildings used "Vermiculite" for this purpose. Some versions of Vermiculite contain Asbestos and must be removed (abated), while others do not. If found, this should be tested. The insulation in the void is there to damp the acoustical resonance of the deck and cavity, and if omitted may cause the floor to be very noisy (i.e. sounds lie a herd of buffalo when performers move across it).
Another item not mentioned was the vapor barrier. This is typically a 3-6 mil thick layer of plastic sheeting that is installed to keep the moisture that seeps from the concrete from attacking the bottom of the floor and possibly allowing mold to grow. Some modern coatings can be painted on the concrete to achieve the same effect if sheeting is not practical. Of course, should you encounter mold when you first disassemble the existing floor, you should discontinue work until it has been assessed to ensure that the spores are not harmful. Black Mold spores can be inhaled and cause severe respiratory problems.
1/4" thick ANSI Class 3 hardboard can't be bought for '20 dollars', nor is it a '90 dollar' replacement - it about 1/2 way between the two. The point of installing a quality hardboard surface (as opposed to a '20 dollar' hardboard surface) is that it may not need to be replaced for 10-20 years (or more), and when it does, you only replace the top sacrificial layer, not the plywood sub-floor (unless there is some significant rot or structural damage issue).
As to the various types of fastening methods, the use of countersunk deck screws at either a 4 x 7 pattern (~16" o.c.) or a 5 x 9 pattern (~12" o.c.) is fairly common. If you place a round paper 'dot' (like the stickers you get at an office supply store) over each screw before you paint the deck it makes it easier to get a screwdriver bit back in the screw slots in the future.
Pre-drilling ANSI Class 3 hardboard, or Plyron can be done by most automated cabinetry shops equipped with CNC wood tools. They crank-out hundreds of complex wood cabinet parts per day, so a rectangular pattern of precisely placed holes to a specified depth is simple and worth whatever price they ask. The precise depth allows each screw head to sit exactly flush to the floor surface, not depressed, not protruding.
A more recent invention by 3M company may make the screw-down approach less common. They have a super-heavy-duty double-sided tape called 'Hurricane Tape' (Type VHB) that is used to secure metal siding panels to the exterior of buildings. It is thin, not like double-sided foam tape, and available in several widths. If you use some strips of this to lay down each sheet onto the sub-flooring, it can later be torn-loose by pulling a piano wire between the sheets to cut the bond. It's not cheap, but it makes a blemish-free floor and it significantly reduces the labor cost of drilling and screwing a bajillion holes.
Not mentioned in this thread is fire-retardancy requirement defined in many building codes. Some are defined in a performance related manner (xx hours fire rating) while others are prescriptive to the construction (2 layers of plywood with a top layer of XX). If you replace your floor with fire-retardant rated material (like Sierra Pine's Medite FR), you can satisfy the fire retardant requirement quite easily and may not need to mix fire retardant into the stage deck paint. Replacing your floor would, under most codes, be considered major constructions and may require a permit, which in-turn, requires that the floor assembly meet current construction codes.
'lwinters360' mentioned that the existing floor might be a "pine / plywood / sleeper / concrete" layering. The ability for a floor to provide some cushioning for performers (particularly dancers but certainly not limited to them) should not be overlooked. Consideration should be made for installing a layer of shock-absorbing rubber between the concrete and the sleepers (which may require reducing the thickness of the sleepers).
Also not mentioned was the in-fill in the floor void between the sleepers. Many older buildings used "Vermiculite" for this purpose. Some versions of Vermiculite contain Asbestos and must be removed (abated), while others do not. If found, this should be tested. The insulation in the void is there to damp the acoustical resonance of the deck and cavity, and if omitted may cause the floor to be very noisy (i.e. sounds lie a herd of buffalo when performers move across it).
Another item not mentioned was the vapor barrier. This is typically a 3-6 mil thick layer of plastic sheeting that is installed to keep the moisture that seeps from the concrete from attacking the bottom of the floor and possibly allowing mold to grow. Some modern coatings can be painted on the concrete to achieve the same effect if sheeting is not practical. Of course, should you encounter mold when you first disassemble the existing floor, you should discontinue work until it has been assessed to ensure that the spores are not harmful. Black Mold spores can be inhaled and cause severe respiratory problems.
