Acquiring jobsite permit approvals
Although the design stage, tile selection, and hot tub location were now finalized, the project could not commence without a permit. The permit approval stage can range between one and three weeks and applies to almost all hot tubs, depending on the size and nature of the project.
Prior to starting any site demolition and excavation work, clearance from all services running above and below grade was requested. Once the permit was approved and utility locates were performed, construction started in early October with the goal of laying the foundation prior to the frost penetrating the ground.
For this project, the demolition work comprised jack hammering aged concrete decking and removing outdated landscaping while at the same time protecting and preserving the structural columns for the upper balcony. Once this was finished, the property was laid out in accordance to the design drawings.
The next step was excavating the location where the hot tub was to be installed in addition to any outer areas that needed to be removed due to unstable ground conditions. This work was completed using a narrow excavator as space on either side of the house was restricted.
The original idea was to sink the hot tub into the ground; however, with the site being close to the house, several structural implications became apparent had the excavation been an extra 0.6 m (2 ft). That said, the homeowner preferred to have the hot tub partially recessed as per the conceptual drawings.
Laying the ground rules
The base (foundation) material is one of the most pertinent aspects when installing a stainless steel hot tub. A solid foundation provides a safe and level platform for which the stainless steel base frame rests. There is no specified nominal thickness for the concrete base, nor does the platform need to be a cementitious material; however, a reinforced concrete foundation with a substantial amount of drainage relief—on the surface and underside of the platform—is preferred and was installed on this project.
Services
Prior to pouring concrete into the foundation forms, consideration for bonding, electrical conduits, drainage, and other provisions for accessory openings were made. Further, before the concrete foundation was poured, several inspections were performed by local authorities to ensure all services were installed correctly and the location of the hot tub was in accordance with the certified drawings.
The vault
Having the luxury to install the stainless steel hot tub above-, mid-, or below-grade provides several options when nesting the hot tub. On this particular project, the foundation was primarily dictated by the elevation as well as the load factor of the walls and size of the hot tub (including the vessel’s weight when full of water).
The walls of the concrete vault were dimensionally assembled and formed on top of the foundation using 15 m (49.2 ft) of rebar installed 406 mm (16 in.) on centre. In doing this, the hot tub’s size and the condensed area for the mechanical equipment were also factored into the equation.
Due to the in situ of the property and house, the mechanical equipment could not be remotely installed; however, there was enough room to keep the equipment separate from the hot tub, but somewhat adjacent to the framework.
Exposing the vault and ensuring accuracy
The walls of the cast-in-place concrete vault were poured 203 mm (8 in.) thick. This method of installation provides the ability to double check for accuracy with respect to measurements and elevations to ensure they coincide with the approved drawings. Further, with the outlining vault structure in place, the customer had a better understanding of the project’s procedures, while also offering some foresight with respect to the overall design concept.
