Hybrid Floor Element and Ground Screw Foundation


In even the most environmentally sustainable projects, a building often resolves its weight and structure on an all concrete foundation. It goes without saying that reducing the use and reliance on concrete in construction is important and its use in foundations is particularly unfortunate in that it permanently alters the ground below us. In a building that is lightweight and has all wood construction, the foundations can be replaced with ground screws instead. The proposal, City Maintenance, examines how New York City’s camouflaged service buildings could be constructed to maintain the city in an expanded way addressing culture, community organizing and events. The typical masonry buildings are often simple storage spaces providing extra square-footage needed for city services. City Maintenance envisions a hybrid of a garden-gallery-storage building that provides space for both utilitarian and cultural services. The proposal presents an architectural plinth, a horizontal surface made with Kerto LVL Q-Panels that can serve as an outdoor deck or as the foundation and ground floor for a multi-story building. Each Kerto LVL column is connected to two ground screws that span two separate Kerto floor elements. Structurally, this proposal is at the extreme end of the spectrum with typical ground screws which are typically used for light-construction and outdoor posts. In order to facilitate the structural capacity, the facade is made in a multi-cell polycarbonate with high insulation values with an architectural fabric wrapping the material to minimize its weight and filter light. Overall, the design maintains itself as a diaphanous prism, open and closed simultaneously. The building's structure emphasizes flexibility and changing use. Each of the floor elements can be customized to integrate additional systems like plumbing or structural rigging into the hybrid helical joint. The plinth emphasizes open accessible spaces for indoor and outdoor use that articulate subtle changes between areas of art display, performance, private social gathering and community activism. The subtle geometry of the plinth maintains the beauty of the garden, but activates it as a civic space as well.

Key benefit

Eliminates concrete entirely with a timber structure and ground screw foundation system

Material list

Kerto LVL Q-Panel
Kerto LVL L-Panel
Kerto LVL S-beam
Kerto LVL Floor Element

Ecological values

Ground screws as an alternative to concrete foundation have some significant benefits, it reduces the CO2 emissions of a project, raising the building allows the topsoil to remain intact and porous and it does not permanently fix a concrete foundation in the earth. The simple examination shows that the same foundation would be around 57 cubic yards (115 tons) of concrete and require 5-6 concrete trucks each to pour their payload directly into the ground to support a building that is entirely above ground (no basement). Consider instead the use of 20 removable and reusable ground screws combined with a wood system… The goal detail connecting the screw with the Kerto floor element was to optimize the prefabrication in order to make the simplest on-site construction as possible. Once placed on the ground screws, the structural helical joint allows the plinth to be leveled off the screws from the top of the floor element as well as tie columns and bracing into the foundation. The joints main detail is an oversized reverse screw that allows the plinth to raise up and down a few inches and retains its structural integrity. The helical joint is also hollow so it can accept other systems like forced-air and plumbing. The hybridization of wood construction and ground screw foundations is particularly interesting as the system benefits from the existing prefabrication knowledge and skill of Kerto LVL floor elements by integrating steel helical joints that can lock into ground screws. The on-site assembly of Metsa systems is already fast and combined with the high-speed deployment of ground-screws the site-prep is as simple as the on-site assembly. The approach of designing a structural ground floor that is directly hybridized with a ground-screw element presents a fully prefabricated solution for a foundation with limited site preparation and extreme versatility for use and load.



  • Economical span (mm)
  • Thickness (mm)
  • Airbourne sound reduction factor (dB)
  • Impact sound transmission (dB)
  • Resistance to fire class
  • Thermal properties





Operation In Progress, Please Wait!!!