Plasterboard of ceilings and lofts

Important notice before building!

Before building the plasterboard loft covering, check the followings:

  • The crust and the foil under it are in perfect condition at the chimney, borders, breakings and the loft is absolutely dry.
  • Is the floor capable of bearing the new load?
  • Is the heat insulation continuous and sufficient between the bonders? (Is all of the surface completely filled)
  • Is the airing of heat insulation insured? (The minimal cross-cut of the lower and upper vents is 200cm2/m2, the suggested width of the air-funnel between the insulation and the safety foil is 4cm).
  • Is the condition of the roof structure adequate?

The plasterboard should not be screwed directly to the bonder or to the binding piece. The galvanized steel CD profile frame and the sprocket (to which the plasterboard can be screwed) that are placed between the adjustable bails are always needed. On vertical and angle flat the maximum axle-spacing of CD profiles can be 40cm, while in case of horizontal dados and partition walls it is 60cm.

Roof structure with a view to heat technology

For the sake of having the loft working perfectly and in good quality, proper heat insulation is needed. Materials made of mineral-wool fiber (e.g. glass-wool heat-insulating blanket) are used as heat insulation. To prevent the possible sweating of the roof, a vapor-tight layer should be placed. The vapor-tight layer should be placed on the "warm" side of the heat insulation. It can be put in between the heat-insulating layers as well. In so far as there were no heat technological calculations, this layer cannot be more than a quarter of the whole heat-insulating layer's thickness. To place the vapor-tight layer unharmed, it is preferable to put it under the space structure (variation "A"). In the space evolved between the vapor-tight foil and the panels the different installations can be lead without going through the vapor-tight layer itself. If the vapor-tight foil does not have a heat-reflecting layer, the space between the foil and the panels can be used for placing heat insulation.

In winter we put heat insulation only in case of placing the vapor-tight layer immediately. If the heat insulation is left without vapor-tight layer, the vapor content of the air can condense in the heat insulation. There is great likelihood of it especially in interiors, where humidity is higher because of the aqueous technological processes.

A) Under the space structure – on bonders or supplementary laths

B) out of the space structure – between the covering and space structure

Placing heat insulation

Put the mineral-wool heat insulating material between the bonders. The width of the material is approximately 10 mm bigger than the distance of bonders. If the heat-insulating material does not stay between the bonders, it can be affixed by packthread during the adjustment. If the sectional-height of bonders is smaller than the thickness of insulation, their height can be augmented with placing supplementary laths. Each of the elements can be placed without gap, fitting close to the elements of the roof structure. The combination of different types of insulation materials is not excluded (rock-, glass-wool). In case of upper exhaust roof structure it is very important to have an upper exhaust layer of the specified height between the heat-insulation and the safety waterproofing. The insulating material can be placed after the construction of frame-structure.

The construction of frame-structure and placing the vapor-tight layer

The frame structure is affixed to the floor- and angle beam-structure (e.g. bonders, binding pieces). The frame structure consists of CD, UD steel profiles and slips. The maximum distance between the CD mounting profiles and the slips is 400 mm.

Why should we use adjustable clips?

  • They ensure the necessary space so that the 5-10 cm mineral-wool insulation material can be placed in front of bonders. By this, ensuring a loft without heat-bridge.
  • It enables an easier and more exact affixation of CD profiles. The rugosity of bonders can be removed, ensuring the constant bearing for the plasterboard.
  • Because of its bow-like shape the adjustable clip is able to dampen the incipient movements in the loft, protecting the plasterboard covering from checking.

For having the structure acoustically independent from the neighboring walls, glue sponge tape (that is adjusted upward) to the UD base profile (slip).

Frame structure built of CD and UD steel profile

Variation "A" – vapor-tight layer out of space structure

  • The vapor-tight layer is affixed to bonders or laths with the help of a stitching-machine.
  • The adjustable clip is screwed to the bonders with two flat-head screws.
  • The CD profiles are affixed to the adjustable clip with the help of two self-catching screws.
  • The CD profiles are pushed into the bounding UD profiles at the juncture of the structure and the face-wall.

Variation "B" - vapor-tight layer out of space structure

  • The CD profiles are affixed to bonders and roof-structures with the help of adjustable clips or direct suspensions. The affixation of adjustable clips and direct suspensions occurs with the help of two flat-head screws.
  • The vapor-tight layer is affixed to CD profiles by tacky tape.

Wood-lath frame structure

In case of wood-lath frame structures, the vapor-tight layer can be placed in two ways:

  • A) Under space structure
  • B) Out of space structure

The vapor-tight layer is affixed to the bonders and wood-laths with the help of stitching-machine. The adjustable clip is screwed to the bonder with two 35 mm wood-screws. The wood-lath is affixed into the adjustable clip with two 25 mm wood-screws. If the distance of bonders is not more than 850 mm, the size of laths is 50/30 mm. In case of bigger distance (maximum 1000 mm) the laths are 60/40 mm in diameter. If the bonders are not completely straight, it can be eliminated with the usage of adjustable clips.

Covering with plates

The plasterboard plates are basically affixed in a way that the lengthwise edge of them should be perpendicular to the mounting profiles and mounting laths. In the course of covering the transversal gaps of plates should be shifted with at least a mounting profile distance (because of the elimination of transversal gaps).

The plasterboard plates are affixed with 25-55 mm long self-tapping screws (depending on the type of frame structure and thickness of covering). The maximum distance of screws placed on the ceiling and the angle flat is 170 mm. After mounting come the grouting and the gypsum plastering of bolt heads.

Vertical plasterboard walls in the loft

The vertical walls of the loft are mounted in a similar way that the free-standing plasterboard wall (from CW and UW profiles) or the plasterboard walls that are affixed to adjustable clips (from CD and UD). The adjustable clips can be affixed on the wood frame structure or on the attic depending on the features of the building. The heat insulation layer runs through the weathering (the lateral plasterboard wall serves aesthetical function) or starting from the weathering, going behind the lateral plasterboard runs in the hidden part of the floor. You always have to be careful not to have heat bridges.