Terraces, patios and rooftops: the outdoor square metre that brings people back to the office
A usable outdoor space, not a facade planter
A usable outdoor space has become an attractiveness argument in its own right: somewhere to have lunch outside, hold an informal meeting in the open air, or simply take a breather between two tasks. In the competition to bring people back to the office, the square metre of terrace matters as much as the coffee machine.But a planted terrace is not just a planter set against the facade: it is a structure that involves the building's load-bearing capacity and waterproofing. Kytom clears these two hurdles first, with the structural engineering office and in compliance with waterproofing standards, before designing the use.
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The challenge
The value of a terrace lies in how it is actually used. A planted strip you look at from the window does not have the same effect as a space where you settle in. Our approach is to design outdoor spaces that are lived in: lunch areas, informal meeting corners, sheltered break spots, integrated with the greenery rather than placed alongside it. This use changes everything upstream, because a frequented space imposes safety, comfort and robustness requirements that mere decoration ignores. It is this ambition for real use that then guides the technical decisions.
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Structural constraints
Permissible load and waterproofing, the two hurdles to clear first
Before any plant, two checks govern the project. The load: an extensive planted assembly weighs in the region of 80 to 150 kg/m² once saturated with water, an intensive arrangement with shrubs and thick substrate frequently exceeds 150 to 350 kg/m². The load path must be validated with the structural engineering office before anything is finalised. Then waterproofing: the assembly rests on waterproofing compliant with DTU 43.1, supplemented by a root barrier and drainage systems, in keeping with the professional rules for planted roofs and terraces. These two points cannot be fixed after the fact: a terrace that leaks or overloads a floor costs infinitely more than the study that would have anticipated them. We address them beforehand, not as an option.
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Design for use
Resistant species, automatic irrigation, furniture and shading
Once the structure is secured, the design favours species suited to the actual exposure, wind, sunlight and urban sea spray, rather than fragile plants doomed to replacement. Irrigation is automated and, where the building allows, controlled by the building management system to adjust supply to the weather. Furniture, shading and surfacing complete the whole to make the space usable for much of the year. Maintenance is planned from the design stage, because a living outdoor space requires regular monitoring: we set it out by contract, at the pace of the selected species.
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Frequently asked questions
What load does a planted terrace represent?
In the region of 80 to 150 kg/m² for a water-saturated extensive assembly, often 150 to 350 kg/m² and beyond for an intensive arrangement with shrubs and thick substrate. This is why the load path is checked with the structural engineering office before finalising the project.
Can an existing terrace be planted?
Often yes, but after a survey. We check the floor's load-bearing capacity and the condition of the existing waterproofing: if it is not compliant or at the end of its life, it is replaced before planting. This preliminary study avoids the main cause of damage, a leak discovered beneath the planted assembly.
What maintenance does a planted office terrace require?
Regular monitoring, more intensive than indoors due to the exposure: automated irrigation to be supervised, seasonal pruning, replacement of damaged specimens, drainage checks. We set out this monitoring by contract, at the pace of the species and the site's exposure.
