OVERVIEW

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Mainstay provided structural engineering services for this private residence.

 

This stately private residence is full of charm and function. With two stories of living space and a finished basement, the structural design of this palatial home is far from ordinary. With the rise of open concept living, gives rise to unique framing and larger spans. This private residence, located in New Hope, PA is not without its structural challenges.

 

This three-story residence has an attached two car garage and a connector trellis path with a porte cochere and auto court leading to a detached two car garage with shell space. This residence is constructed of wood framed construction. The roof is constructed of plywood sheathing supported by wood roof trusses spanning to wood bearing walls or engineered wood girder beams. The floors are constructed of Warmboard-S plywood decking subfloor. This system integrates plywood with tubing to create a unique radiant flooring system. With its 7-ply plywood panel and tubing, it creates a 1 1/8” thick radiant panel, which allows it to become the main structural decking. This decking is supported by manufactured I-joist spanning to bearing walls or engineered wood girder beams, except at the first-floor level.

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CHALLENGES

To create a more open concept feel in the basement, the owner requested to minimize the use of interior columns. Mainstay was asked to review the current framing documentation and determine the necessary framing to eliminate unwanted columns. Structural steel wide flange beams were introduced to facilitate this request. An additional design challenge was to create the cantilevered framing for the bridge area, on the second floor, that overlooked the main entrance below. In order to create this flush framing, metal strapping was used on top of the floor joists and extended from the cantilevered section over the girder beam and back to the floor joist back span.

 

The foundation walls for this residence did not use typical cast in place concrete or concrete masonry units. The owner opted to use Superior walls systems, which are insulated precast concrete wall panels, which allowed for faster installation of the foundation walls. The panels are joined together using bolts at the top and bottom and a polyurethane sealant is used for the full height of the joint. The panel is designed with its own steel reinforced footer beam so it only needs to be placed on a bed of crushed stone. The depth of the crushed stone is determined by considering the allowable soil bearing capacity of the building site and cross referencing with the combined footing load per linear foot.