The specified slider does not exist.
Raised baseplates
Where top-mounted guards are used, managing the risk of water entry on the horizontal surface is critical. Raising the baseplates higher than the field of the balcony (Figure 13) allows water to be deflected around the anchor penetrations, providing inherent protection. This approach does not eliminate the penetrations in the horizontal surface, but is a strategy for risk mitigation and redirection of the water. A curb, wood blocking, or aluminum shims can be used to raise the baseplate. Consider guard dimensions, including height, climb-ability, and opening size relative to building code requirements. If re-using existing guards, alterations may be required. Many newer guard systems can accommodate raising baseplates without exceeding maximum allowable opening size from the top surface of the balcony to the underside of the bottom rail (Figure 14). Re-using existing guards can provide substantial cost savings.
Side-mounted and wall-mounted guards
In lieu of top-mounted guards, side-mounted guards are a reasonable alternate to minimize the impact of penetrations through the membrane. Continuity of the membrane and providing a gap between the rim joist or fascia and the guard rail for drainage and drying are key considerations for this design to work. Transitioning away from top-mounted guards may be critical to address these issues in the long-term. If implementing on existing balconies in a restoration setting, there may be increased costs for new structural design and blocking installation required to accommodate the side-mounted guard.
Side-mounted guards also eliminate the risk of fasteners connected only to sheathing. Although a common structural and procedural issue with top-mounted guards is beyond the scope of this article.
Another approach is to have wall-mounted guards and avoid penetrations through the membrane at anchor points altogether. Guards may be connected to adjacent wall assemblies, columns, or structural posts. There are other risks associated with this approach that must be considered; however, these are beyond the scope of this article as well.
Terminations
Terminations in the sheet waterproofing membrane represent a high risk for water ingress leading to wood rot. Terminations include perimeter upturns at balcony doors, cladding, columns, and downturns at balcony slab edges.
Upturns
Upturns at balcony doors, cladding, and columns require membrane flashing upturns to prevent rainwater and snow build-up/melt from getting behind the membrane. A sealed upturn with a minimum height of 100 mm (4 in.) to 150 mm (6 in.) is appropriate for most installations where the waterproof membrane does not interface with an adjacent through-wall or sub-sill flashing. A durable detail requires a minimum upturn height, securement, and a durable seal at the top edge of the membrane. The seal at the top edge should also be protected with a metal flashing and sealant, providing further redundancy.
Where upturns are not sealed, or where the termination is sealed, but there is no upturn at all, the wood structure is at an extremely high risk of water exposure. Inside and outside corners at upturns present additional detailing challenges and risks.
At upturns, the sheet waterproofing membrane is adhered to the adjacent building material (e.g. brick or wood sheathing) and the top edge is sealed with sealant to prevent water penetration. As the adhesive ages and fails and where there is no additional restraint, the waterproofing will debond and come loose (Figure 15 and Figure 16), increasing the risk of water penetration and further debonding of the membrane.
Rather than relying solely on the adhesive for membrane securement, a fastening bar should be used to provide mechanical restraint. A weather tight seal can be provided at the membrane layer by providing self-sealing butyl tape against the membrane prior to the fastening bar and fastener installation. Further redundancy against water penetration can be provided with a prefinished metal counterflashing terminated into a sealed reglet to protect the top edge of the membrane and conceal the fastening bar.
The same watertightness and redundancy principles apply at inside and outside corners, and post penetrations. Cuts and seams should be reduced or avoided wherever possible by folding the membrane (e.g. at inside corners). Protect all upturns with continuous fastening bars, seals, and counter flashings.
No upturn
When the sheet waterproofing membrane is not upturned onto an adjacent building material, the waterproofing is typically terminated with a bead of sealant. There is no water management redundancy with this approach. As the perimeter sealant ages and fails (Figure 17), water penetration around the membrane is inevitable. At balcony doors, this can result in ledger board deterioration or detachment, or wood rot at a critical location of a cantilevered support beam. Further, this presents high risk of water leaks into the wall system and building interior.
At columns, this can result in wood rot (Figure 18) and rapid loss of structural capacity. Further, this issue is often concealed from view or easy inspection by metal flashings and balcony enclosures and soffits. Like balcony guard baseplate penetrations, this mechanism does not result in a water leak to the building interior. Water penetration can go unchecked for years as deterioration progresses. Locations with no upturn are not durable and should be avoided.
