Plasterboard can be used to expand the attic of a new building as well as the existing attic space of an old building quickly, cleanly and efficiently.
Roof conversion systems with plasterboard consist of a seamless cladding as a finished room surface, which is attached to the roof truss either directly or via metal or wooden substructures. In the level of the substructure, there can also be an insulating layer of mineral wool, as an internal supplement to the actual pitched roof insulation or to meet e.g. sound insulation or fire protection requirements.
This Bauwion knowledge page describes the conversion of the room-bounding surfaces into a wooden roof truss, in detail the production/cladding of the following surfaces with gypsum boards:
1 = sill / sloping roof | 3 = collar beam ceiling (soffit)
On the knowledge pages ► 420 | Drywall and ► 430 | Plasterboard ceiling cladding and suspended ceilings , further drywall systems are described that can also be used in attic conversions.
the substructure: The maximum permissible spans of the planking in accordance with DIN 18181 or the respective building authority approval must be taken into account. In the case of wooden substructures, the wood used must meet at least quality class S 10 (MS 10) according to EN 1912 and must contain no more than 20% wood moisture by mass.
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Acoustic ceilings: The installation of perforated sound-absorbing plasterboard with fleece lamination on the back is also possible for attic conversions. It improves the so-called reverberation times of a room, which depend not only on the volume of the room, but also on the sound absorption capacity of the room surfaces. Reverberation times that are incorrectly or not taken into account for the respective use can lead to the unusability of the room in certain rooms, e.g. gymnasiums, if, for example, communication is unreasonably difficult due to excessively long reverberation times. Further information can be found on the knowledge page ► 430 | plasterboard ceiling cladding and suspended ceilings.
Visible clothing under fire protection clothing: Even in the case of roof conversions, it may be necessary to design the cladding in two levels if one system alone cannot meet all technical requirements at the same time, e.g. in terms of acoustics and fire protection. The acoustic cladding is then mounted as a second level under cladding with classified fire resistance. Both systems must be coordinated with each other and approved accordingly. In particular, the substructure of the fire protection clothing must be designed and approved for the additional load caused by the acoustic clothing.
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Partition wall connection: In order for a partition wall with fire resistance requirements to be able to connect to a roof cladding as a room-enclosing component in accordance with the approval, at least the same fire resistance must be proven for the roof cladding as for the partition wall.
Damp rooms: According to DIN 18181, gypsum products are generally not suitable for applications in rooms with persistently high humidity. However, they are suitable for rooms in which the humidity only rises briefly due to use and due to sufficient ventilation options, e.g. in sanitary rooms within apartments. DIN 18181 recommends gypsum boards classified according to DIN 18180 (type GKBI/ GKFI) or DIN EN 520 (type H2) for damp room applications.
Ball impact safety: If ball impact protection is required, e.g. in gymnasiums, it must be checked whether the selected roof extension system is suitable and approved for this purpose. As a rule, ball impact safety in this case requires a reduced center distance of the support profiles/battens.
Information in the building documents: In accordance with DIN 18168-1, the building documents must specify the use of plasterboard ceiling cladding and suspended ceilings, including their anchoring and the attachment of light partition walls to them. Any necessary measures for fire, heat and sound insulation must also be specified.
Storage of plasterboard: The storage of plasterboard should be horizontal and even, i.e. e.g. on dry pallets or tightly lying lumber. When storing plasterboard, the permissible static load limit of the ceiling is quickly reached. The panels must therefore be stored taking into account the weight of the panels and the permissible ceiling load-bearing capacity, with as much distance as possible between the individual pallets.
Processing of gypsum boards: Gypsum products must be protected from the effects of moisture on the construction site during transport, storage and installation. Gypsum boards in particular are quickly damaged by moisture, but also by deformation. Material delivery and processing should therefore only begin when the façade envelope including the roof offers functioning protection against moisture/precipitation. After installation, gypsum boards should not be exposed to prolonged humidity above 80%. Sufficient ventilation must be ensured, especially when interior plastering or screed work is carried out at the same time, in order to avoid damage to the drywall walls due to increased humidity.
Plasterboard filling: According to DIN 18181, plasterboard should only be filled at room temperatures ≥ 10° C.
Analogous to the four quality levels Q1 – Q4 defined in DIN 18550 for interior plaster surfaces, these are also specified for gypsum boards in Leaflet No. 2, Filling of gypsum boards, see also Lexicon article ► Filling of plasterboards, quality levels. The quality level is to be selected depending on the further coating/cladding of the wall.
It should be noted that markings in grazing light can never be completely avoided due to the handcrafted production of the smooth wall surface. However, they are significantly reduced when an increased quality level (Q3 or Q4) is executed. At quality level 4, they are minimized within the scope of the craftsmanship possibilities, but an absolutely flat and shadow-free execution is not feasible. For an optimal result, comparable lighting conditions should already be available during the execution of the filler work as during acceptance or later use.
DIN 4102-2, fire behaviour of building materials and components; Components, Terms, Requirements and Tests
DIN 6812, Medical X-ray Systems up to 300 kV - Rules for the Design of Structural Radiation Protection
DIN 18168-1, Plasterboard Ceiling Cladding and Suspended Ceilings - Part 1: Requirements for the Design
DIN 18180, Plasterboard - Types and Requirements
DIN 18181, Plasterboard in Building Construction - Processing
DIN 18182-1, Accessories for the processing of plasterboard - Part 1: Profiles made of sheet steel
DIN 18340, VOB Procurement and Contract Regulations for Construction Services - Part C: General Technical Contract Conditions for Construction Services (ATV) - Drywall work
DIN EN 520, Plasterboard - Terms, requirements and test methods
DIN EN 13964, Suspended ceilings - Requirements and test methods
DIN EN 14195, Metal Profiles for Substructures of Plasterboard Systems - Terms, Requirements and Test Methods
Building Rule Lists, Building Rule List A, Building Rules List B and List C, published by the ► German Institute for Building Technology (DIBt)
Construction Site Conditions, Leaflet No. 1, Notes and Guidelines for Drywall Work with Plasterboard Systems, published by the Gypsum Board Industry Group in the Federal Association of Plasterboard Gipsindustrie e.V.
Filling of gypsum boards, leaflet no. 2, surface qualities, notes and guidelines for drywall construction work with gypsum board systems, published by the gypsum board industry group in the Federal Association of the Gypsum Industry e.V.
Gypsum Board Constructions, Joints and Connections, Leaflet No. 3, published by the Gypsum Board Industry Group in the Federal Association of the Gypsum Industry e.V.
Source: bauwion
