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Plastered Hollow Brick and Growing Aid Systems

This page belongs to 'plaster masonry'. Houses of plastered hollow brick have been built since 1930, on such walls are growth cable systems of FassadenGrün, ie all assembled kits are stainless steel and almost fully applicable. However, different problem areas should remain recessed, and with thick special plaster, problems can occur. On this page you will find this detailed information, also about the history and characteristics of hollow block bricks and for drilling in hollow masonry. Exposed hollow blocks, ie. As for clinker or bricks, they are discussed under 'exposed masonry'.

Properties of plastered hollow Masonry

Since about 1930 were bricks not only massively made as 'solid brick', but made with holes as a 'perforated bricks'. Initially this was done because of material savings and lower costs while burning, but also to better 'interlock' the stones when laying on the mortar layer. For buildings that were built from this time, such cavities are often to be expected in the masonry. From about 1950 there were also plastered hollow blocks of concrete, partly filled or foamed. Later came increasingly the subject of 'insulation': with bricks with cavities significantly less heat can escape from the house as solid bricks. The hollowed stones were continuously optimized and there are now made with 'more holes than stone'. A trick - the insulation values ​​are increased even further: In the kneading process the clay will have additives such as sawdust or similar mixed in, which burn off in the fire of formed bricks, leaving porous cavities in the already thin webs... Particularly well known are here 'Poroton' stones ( 'porous clay'). In addition there are stones where the foamed hollow chambers are filled with insulating material.

Basically hollow bricks are now chosen by those with a dense or porous structure, the latter as described as having a lower strength in the webs. The degree of porosity is difficult to see from the outside, most likely by the weight of the stones.

Exception: A double-wall masonry

In exceptional cases plastered hollow bricks are used as the outer shell of a 'sandwich' facade. Behind a 10 cm thick, plastered hollow brick wall, when drilled then a larger cavity of turn of about 10 cm thick, which is filled with air and / or insulating material before the actual load-bearing wall of concrete or other masonry units followed. Such facades are to be considered 'Weather shells' and only limited suitable for attachment of growth aid systems.

Problem Areas

Windows with plastic roll down blinds- or blind boxes, is best not drilled into. Also on windows (lintels) and in the area of ​​ceilings, ring beams , and wall integrated supports. It often happens that these are offset appearing as concrete components and dressed flush with the wall with special sandwich bricks along with integrated insulation before the final plaster is uniformly applied. Thus warm bridges are avoided in the area of the concrete parts. At single places or (with older constructions) also extensive along these problem zones is to calculate with a direct layer of heat insulation (4 - 6 cms). Here it can become impossible to fasten standard holders for a growth aid system or a trellis - see below. These places are not really visible on plastering, however, are recognizable by light tapping and listening before the beginning of the drilling works.

One problem can also be special plasters with more than 2 cms of strength.

Cable Systems for hollow Masonry

Basically here all constructions of FassadenGrün are suitable, the Massive with WM 12153 but with the restrictions made there, especially in very light vertically perforated bricks, where the strength of the stone material is still severely restricted. In the problem areas mentioned above, Cross holder WM 12XX2 might be necessary too. If plastic dowels such as DH 10065 are used, each larger variant is preferable.

Holes in hollow Bricks

Such walls are easy to  drill into. All drill types can be used from FassadenGrün. The above, insulated zones, should not be drilled into or at least treated separately, by knocking lightly on the wall before the commencement of drilling, to inspect the situation. Hollow blocks with a high proportion of air chambers ( 'Poroton') are generally drilled without hammering or the hammer function, because otherwise flaking arises in the narrow webs and the sustainability of anchoring decreases drastically. Therefore, pre-drill with a smaller drill bit. Problems can occur when drilling in border areas of the webs and the hole 'runs away' and is wrong. By drilling and gluing the anchor via composite mortar can this be corrected. Please use the general remarks under drilling.

Growth cable system 4030 on a vigorously colored wall of hollow bricks (vertically perforated bricks)
High grade stainless steel wire trellis
Vertically perforated bricks for shoring, high proportion of holes and porous microstructure
vertikally perforated bricks, poroton
New construction with hollow bricks, partial installation of insulating Styrofoam plates of possible thermal bridges, in addition to the surrounding cladding of the concrete ceiling. (Photo detail above)
Hollow bricks with insulation
Mixed construction hollow brickwork (reddish brown) and made with thermal insulation (white pink) laminated concrete columns. In the back of an insulated support is integrated into the masonry.
mixed construction hollow brickwork
Double shell wall construction: supporting concrete wall, insulation, exterior shell made of hollow bricks with stylistic elements
double-leafed hollow brick masonry