Ventilated facade design

What the design package contains

A ventilated facade has three layers that have to work together: the cladding, the ventilated air gap and the insulation fixed to the wall, all carried by a metal subframe. Each layer has its own failure modes — a bracket that pulls out of a hollow block, an air gap too narrow to dry the insulation, a panel that buckles because nobody left room for thermal expansion. The design package exists to close those gaps on paper rather than on the scaffold.

Structural calculation: wind, weight and earthquakes

The subframe carries the weight of the cladding and the insulation, the wind pressure and suction on the facade, and the inertial forces during an earthquake. Wind pressure in Georgia is taken from the construction climatology regulation (Annex 5 to Government Resolution No. 71 of 15 January 2014), which gives values by settlement. Seismic intensity comes from the seismic regulation in Annex 3 to the same resolution: 8 points on the MSK-64 scale for Tbilisi and Kutaisi and 7 for Batumi, refined by local microzoning where it exists.

The seismic regulation requires non-structural elements whose collapse could cause casualties to be checked for the design seismic action together with their supports. A facade cladding panel falling from the tenth floor is exactly that case, so we check the panel fixings, the brackets and the anchors, not only the main frame of the building.

Anchors deserve particular attention. The pull-out capacity of the same anchor differs several times between concrete, solid brick and hollow ceramic block. We specify anchors with a European Technical Assessment for the base material in question and, where the wall is unknown, ask for site pull-out tests before the bracket spacing is fixed.

Thermal design and energy performance

Georgia's Law on Energy Efficiency of Buildings (2020) and the minimum requirements approved by Government Resolution No. 354 of 13 July 2021 divide the country into three climate zones. In the original text of the resolution the maximum U-value for external walls is 0.50 W/m²K in zone 1 (Batumi, Kutaisi), 0.38 in zone 2 (Tbilisi) and 0.25 in zone 3 (mountain areas such as Tianeti). We check the values against the consolidated version in force when your project is submitted.

The brackets of a ventilated facade pass through the insulation and act as point thermal bridges. Depending on their number and material they can reduce the effective thermal resistance of the wall noticeably, so we include them in the calculation and, where needed, specify thermal break pads or a subframe with fewer, stronger brackets.

Fire safety of the facade

The Building Safety Rules approved by Government Resolution No. 41 of 28 January 2016 are based on the International Building Code and apply to buildings of classes III to V. Chapter 14 deals with exterior walls: for buildings above 12 m with a combustible water-resistive barrier it can require testing to NFPA 285; metal composite materials such as aluminium composite panels have their own article with requirements for flame spread, smoke development, thermal barriers and full-scale testing; there are separate provisions for high-pressure laminate cladding.

European reaction-to-fire classes (EN 13501-1) are not the primary route in this regulation, but manufacturers often hold them. We match the documents each product actually has to the requirements of Chapter 14 and design fire breaks in the air gap where the building height and the materials require them.

Drawings an installer can follow

Most problems on site come from details nobody drew: how the cladding turns around a window reveal, where the expansion joint goes, how the subframe passes a balcony slab. We draw every typical and special node and give the crew panel layouts with dimensions and numbering, so that panels are cut in the workshop rather than adjusted on the scaffold.

We work in Revit and AutoCAD and can deliver the model and drawings in the format your architect or general contractor uses.

Expert review and permits

Under the Rules for Issuing Construction Permits (Government Resolution No. 255 of 31 May 2019), expert review of the structural design is required for buildings of class II and above, and of the detailed architectural design for classes III and IV. Facing and repair work on an existing facade that does not significantly change its dimensions or appearance does not need a permit, but a new facade on a new building is part of the permitted design. We prepare the facade section so that it answers the reviewer's questions before they are asked.

What to send for a quote

• Elevations, floor plans and at least one section (PDF or DWG).
• Address of the building — it defines the wind, seismic and climate zone.
• Wall material: reinforced concrete, brick, ceramic or concrete block.
• Preferred cladding and colour, or the look you want to achieve.
• Stage of the project and the deadline for the drawings.