Lightweight to medium-weight attachments
ETICS Expert Tip – Part 3
This is what matters when it comes to fasteningBuilding facades have to support a variety of attachments, such as awnings, marquees, railings, lamps, letterboxes etc. ETICS facades hold special challenges when it comes to fastening.
As a rule, the different attachment parts are divided into the following groups:
- heavy and
- safety-relevant attachments.
Our current Expert Tip deals with lightweight and medium-weight attachments. Lightweight attachments are those with an acting load of up to 5 kg, medium-weight attachments are those with an acting load of up to 15 kg.
For information on fastening heavy and safety-relevant attachments, please refer to our ETICS Expert Tip – Part 4, which we will publish on 1 July 2022.
In principle, all fastening solutions for attachments on thermally insulated facades must meet the following requirements:
- Safe load-bearing capacity and load transfer in the substrate / insulating material
- Weather resistance and rain-impermeability
- Minimisation of thermal bridges
In addition, the functionality of the ETICS must not be impaired by the attachment or the corresponding fastening solution.
Improvised solutions such as steel or wooden constructions only rarely meet these requirements. The following errors/damages often occur in such cases:
- Problems with connections/seals
- Load-carrying capacity too low/deformations too high
- The durability of the materials in the system is unclear (e.g. wood may rot)
How to find the suitable fastening solution for the attachment part to be fittedThe selection of the optimal mounting element is determined by the acting loads of the attachment as well as the moment of assembly. The acting loads are essentially composed of the weight load of the attachment, the payloads (variable loads) and weather-related effects. You can find out more about the different loads in our next Expert Tip part 4.
Fastening of light attachments (up to 5 kg per attachment)Depending on the insulation material, lightweight attachments can be fastened directly in the insulation plane.
Fastening of medium-weight attachments (up to 15 kg per attachment)Medium-weight attachments must be fastened in the substrate in order to be able to transfer loads reliably and permanently. For safety-relevant fastening, an approved fastening is required. Overhanging components offer a large target surface for wind and snow loads and therefore also require a building authority approval (e.g. satellite dishes).
Left: Example of fastening an attachment up to 5 kg (here house number), fastening in the layer of insulation. Right: Example of fastening an attachment between 5 and 15 kg (here rainfall pipe), fastening in substrate.
The moment of assembly is importantThe moment of assembly is the second important selection criterion for the correct fastening solution. Here, a distinction is made between "fastening before or during the installation of the ETICS" and "subsequent fastening".
Attachments can also be fastened before and during the installation of the ETICS, but also afterwards.
Fastening before or during installation of the ETICSIn this case, the exact positioning of the attachment is already known before or during the installation of the ETICS. The fastening solutions for attachments can be integrated directly into the external thermal insulation composite system.
Subsequent fasteningOftentimes, the position or the kind of attachments which are to be mounted to the building envelope has not yet been planned. The installation takes place subsequently on an ETICS facade that is already completed.
With the Iso Team, EJOT has compiled a product group for the planned and subsequent fastening of attachments to ETICS facades which offers a solution to all fastening problems.