- General concepts of framework systems and subsystems
- Load-bearing and special tasks of the frame
- Varieties of galvanized steel profiles
- Profile accessories
What is required to assemble a frame for plasterboard cladding? The catalogs of complete systems are full of various products, while the user knows for the most part only rack and guide profiles for gypsum board. Today we will eliminate the lack of knowledge by talking about the most popular elements of frame systems for drywall.
General concepts of framework systems and subsystems
Understanding the key principles of constructing a frame of structures made of gypsum boards helps to achieve three main technological tasks:
- Correct specification and the most profitable purchase of materials.
- Fast and convenient assembly of the structure, even in confined spaces.
- Compliance with the required indicators of strength and reliability, long service life.
For ceiling, wall structures and partitions, there is a different approach to the construction of the frame system. Wall cladding aims to align the planes for further work and provide them with the required punching resistance. The frame in this case serves as a kind of base for the cladding, maintaining resistance to frontal pressure and supporting the impressive weight of the cladding sheets.
Partitions are more complex. Their frame must withstand frontal impacts in opposite directions, provide a sufficiently powerful base for fixing the cladding, door blocks and mounting of various installations. A secondary task is to ensure a sufficient volume of the cavity inside the partition, in which thermal and sound insulation is placed.
The forces acting in a suspended ceiling frame are fundamentally different from other systems. Fasteners of the entire structure to the ceiling take on the main static load. At the same time, the frame itself must ensure ideal flatness, because the ceiling, unlike walls, is characterized by a larger area, and to exclude the effects of sagging and warping, and this can be quite difficult.
Very often, framework systems are made multi-level to distribute functional goals on each of them. Thus, the base (or main) frame provides sufficient rigidity and reliability, and the bearing part performs the function of fixing the sheets, aligning them or shaping them..
Load-bearing and special tasks of the frame
The main system of profiles, otherwise called a subframe, is distinguished by the presence of attachment to the structural part of the building. The subframe is formed on the basis of two lines of the guide profile, forming a kind of frame. The profile has straight side flanges, which allows you to insert into it rack profiles of the corresponding width.
This principle is common to most systems, with the exception of the position of the rack-mount profiles. In wall and ceiling cladding frames, the rack profile is oriented by the central shelf to the back surface of the sheet. In partitions, the drywall is attached to the side shelves of the racks on both sides, while the cavity of the rack profile allows you to place the filler without air pockets.
In systems with single-layer cladding, the main part of the frame most often also combines a load-bearing function. For more loaded structures, a counter-lattice is performed: the supporting frame duplicates the main one, but in the transverse direction. Such a system has the best indicators of rigidity and allows you to perfectly level the surface..
In addition, there is a third level of the frame system. It is represented by local structures that are built to obtain all kinds of architectural elements: vaults, arches, multi-tiered ceilings, parapets and cornices. Since such frames do not have a functional load, they are assembled in any convenient way to ensure overall strength, integrity and correct geometry..
Varieties of galvanized steel profiles
The entire construct described above consists of a very limited set of elementary components. If we neglect the variety of standard sizes, it turns out that only two types of profile are used in the frames for structures made of gypsum board – rack (PS) and guide (PN). Their main difference is that the guide profile does not have curved edges on the outer shelves. Due to this, it does not have the necessary rigidity, but it is excellent for performing its functions..
1 – rack profiles; 2 – guide profiles
A more visual representation of the profile varieties is provided by the Western-style marking. According to this nomenclature, profiles of types UD, CD, UW, CW and UA are distinguished. The first letter determines the form factor of the profile, that is, the presence and absence of stiffening ribs on the outer shelves. The second letter indicates the scope:
- D – ceiling (conditionally);
- W – ordinary wall;
- A – reinforced wall;
According to the size table, all profiles are grouped into sets. So, CD-60 is only one of the two parts of the kit of the same name, the second is the UD-27 profile. The regularity here is that the thickness of the rack profile always corresponds to the distance between the shelves of the guide. Other examples of kits include CW-50 and CW-100, in which the digital index is nothing more than the value of the width of the guide profile and, accordingly, the thickness of the rack.
Ceiling profiles are produced in sets of two standard sizes. The CD-60 set is the most demanded and is the basis for all ceiling systems. It is also used as a supporting profile, but it is often replaced by a more compact CD-47, ideal for a set of small architectural elements: caissons, niches, capitals and pylons. In ceiling structures, the use of such a profile is explained by the same principle as the use of thin 9 mm drywall sheets: the lower the final weight of the suspended structure, the higher its reliability and safety.
Among the wall varieties, there are three standard sizes of sets: 50, 75 and 100 mm. They do not differ in shape, and the choice in favor of one of them is determined by the functional purpose of the wall or partition, its thickness, the desired degree of sound insulation and, accordingly, the amount of filler to be laid. As you may have guessed, the weight of the profile and sheets is not critical when working with wall structures..
The profile manufacturer is one of the most important guidelines when choosing. Different companies use steel of different qualities, their profiles differ in the thickness of the metal used, the stamping scheme and the quality of the protective coating. Individual manufacturers also offer their know-how to make the frame system easier to work with. Examples include a series of Ultra wall profiles with a unique punching pattern and special type of technological holes..
In addition to galvanized purlins, many suppliers offer about a dozen special elements to simplify installation. They can be conditionally divided into fastening nodes and suspension systems.
Of the knots of fastening, the most common:
- Profile extension connectors.
- Cross connectors (crabs).
- Nodes for T-junction.
- Multilevel brackets for fastening the main and supporting frames.
Hanging elements are not that numerous. With a level difference of up to 120 mm, direct suspensions are used, they are also U-shaped brackets. With a greater descent of the ceiling structure, it is suspended on hardened steel spokes up to 4 mm thick. In this case, the main part of the frame is attached to the spokes by means of special clamps with adjusting plates.
The accessories described above are used together with the CD-60 set when working with ceiling structures and false walls. From the entire list, only straight hangers are universal; they can be used when constructing a frame for wall cladding from sets CW-50 and CW-75. In the construction of partitions, special components are almost never used..