In 2021, according to the order of the Minister of Transport, Construction and Water Management of 5 July 2013, we will have another obligation to reduce the heat transfer coefficients. We have had almost four years since the introduction of the regulation, and there is still a lively debate on this issue in the stonemasons community. The need to follow a new reality forces us to look for new solutions, both in relation to thermal insulation and anchoring.

Until recently, stone facades were installed mainly with the help of classic anchors. In 2014, Specialinsert introduced a new way: Keep-Nut. The new assembly technology was developed in Italy by a team of professionals with many years of experience in production and development of fastening systems. Specialinsert offers a wide range of fasteners used not only in the stone industry, but also in the shipbuilding, automotive, railway, furniture and many other industries.

Keep-Nut – it can be called a mounting insert or a threaded insert – is an anchor whose structure is based on a system of steel bits placed at right angles. Thanks to this construction, it is mechanically self-anchored and does not require any adhesives. During the stress tests, the insert remains undamaged and a part of the material is torn off. The certified strength is 250 kg for a double-sided insert when installing granite and 150 kg for installing sandstone.

The advantage of the system, especially on facades, is the possibility of using any compositional system. There are no restrictions on the choice of the type of profiles, their thickness and the method of installing the insulation material. This is of great importance in the context of new requirements for the insulation of building facades.

Keep-Nut allows the use of thinner facade panels than is required for conventional anchors, because the installation is done from the back, not from the side. We can use it for panels with a thickness of 7.5 mm. The manufacturer’s experience shows that thirty-millimetre-thick slabs are most often used for sandstone, while forty-millimetre-thick slabs are not used at all. Granite and other high density materials may also be thinner than before. The only determining factor here is the strength of the material.

Using Keep-Nut forces you to change your approach and use slightly different methods than your existing anchor systems. The Specialinsert system requires relatively precise hole drilling, but – unlike other rear mounting systems – they can be drilled with standard tools and drills. To achieve the appropriate hole diameter, the manufacturer recommends the use of cylindrical drills with a diameter of 12 mm or a standard drill with a diameter of 11.8 mm. The anchor is installed by hammering, usually by pressing with a finger, without the use of adhesive.

Keep-Nut has EOTA technical approval for ventilated facades and a certificate from the German Institute of Building Technology DIBt. It is made of polyamide and steel, so it is a non-flammable element of the structure, which is confirmed by the relevant certificate.

Facades are just one of many ways to use this product. As examples from all over the world show, it can also be used to: hang sinks, fasten table bases or wall hangers, or in kitchens made entirely of stone. The only limitation is your imagination.

Source: Kurier kamieniarski

Author: Bogumił Czopik | Published: 28.05.2017