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HÜWA lexicon

Formwork equipment and concrete building material


Spacers are mounting parts which ensures the necessary laying dimensions between the outer reinforcement bars and the formwork. Spacers can be designed punctiform, linear or laminar. Numerous forms and types for nearly every area of application in the reinforced concrete construction at the job-site were developed within the last years.

Concrete cover

As concrete cover in reinforced concrete construction the distance between concrete surface and outer edge of the concrete coated reinforcing steel is described. Concrete cover is guaranteed by use of plastic spacers (such as concrete balls).


In the concrete, which is little resistant against tractive forces, steel is inserted to collect the tractive forces or additional compressive forces. The so-called reinforced concrete. The special concrete insert is called reinforcing steel or concrete steel. For laying of the reinforcement a reinforcement plan will be constructed. In case of mechanical prestressing we talk about prestressed concrete.

Binding wire or tie wire

To fix it for concreting, the reinforcement will be bound with binding wire.

Chamfer strips or tie wire

Commonly used to break edges of precast concrete parts. They enable a clean finish. Chamfer strips will be used in precast factories as well as on construction sites. According to the field of application, strips of plastic or timber are recommended.

Fiber concrete spacers

At the production of fiber concrete spacers the relatively solid raw material is charged with fibers and pressed through forms mechanically. That way the spacer gets the required form. With this procedure single spacers (e.g. bones) as well as surface spacer (e.g. serpent with and without knobs) can be produced.

Cast concrete spacer

At the production of spacers made of cast concrete, the concrete will be filled in plastic forms. After curing, the spacers will be removed from the form and will be packed. According to available plastic forms, single spacer like e.g. HÜWA-Betofix, HÜWA-Rubeton, HÜWA-TFD etc. and surface spacers can be produced with this method.


Cast concrete spacer with 4-point contact surface. It is used in many precast factories in Germany, Austria and Czech Republic. Betofix was one of the first products HÜWA manufactured.

HÜWA-Bock (with six or four legs)

Steel spacer, made of 6 mm construction steel, with different foot equipment, e.g. concrete foot, large surface foot or standard fitting with formwork protection (plastic cap). HÜWA Bock 500 is certified by DBV-data sheet (see test certificate). HÜWA-Bock is used in reinforcement technology especially at installation of heating and cooling systems (component activation).

Mat cutter

With bolt cutter related cutting device, especially constructed for use on construction sites. It allows the concrete worker a fast cutting to length of the reinforcement mats. The long arms of the tool ensure high power transmission. The cutting blades consist of hardened steel.

Thermal component activation – concrete core temperature control

An old idea and its modern use.

Already the old Romans knew about the use of a surface heating and heated their rooms with underfloor heating, the so-called hypocaust. The heat was led through canal-like tubes under the floors by stoves. Naturally some things changed since the Romans. These days we use thermal component activation. A system which uses building masses for temperature regulation. At building of solid ceilings, or sometimes also of solid concrete walls, pipes will be laid. Water as heat or cool medium flows through these pipes. The whole floated concrete ceiling or wall will be thermal activated as transfer and thermal storage mass and creates a comfortable indoor climate. The use of ceiling cooling leaves out the installation of an air-condition. Special spacers like e.g. the four-leg (HÜWA-Bock 300) or the six-leg (HÜWA-Bock 500) are used in connection with cast concrete spacers or fiber concrete spacers for the lower reinforcement.

In-situ concrete

Describes concrete, processed on-site at the construction site and (mostly in a formwork there) set.

Around 1755 the development of concrete starts with the Englishman John Smeaton. He was searching a water-resistant mortar and carried out tests with burnt limes and clays. Thereby he determined that for a self-hardening (hydraulic) lime a certain percentage of clay is necessary. In 1796 the invention of the Roman cement of the Englishman J. Parker, as well as the Portland cement of his compatriot J. Aspdin in the year 1728, initiated the modern concrete construction. The invention of reinforced concrete of Joseph Monier (patent certificate: 1867) was another big development leap. Nowadays the reinforcing steel is named Monier-iron occasionally. 

Exposed concrete

If concrete parts won’t be plastered or veneered we speak of exposed concrete. The concrete surface fulfills creative functions. Often the surface is designed with a specific structure which is possible through the application of special formworks or formwork inserts. Especially at exposed concrete parts you have to pay attention of a suitable selection of spacers. This spacers becomes apparent slightly at the surface through contact with formwork. If this is not preferred that effect can be minimized by use of exposed concrete spacers.

Distant spacers

Distant spacers are mounting parts ensuring the upper reinforcement in its position. They distinguish themselves by their type of construction, supporting height and purpose of use. It distinguishes between linear distant spacers (steel basket or U-basket) and punctiform distant spacers (spacing trestle, 6-leg, 4-leg).


The materials belonging to compost are first of all the classic materials, arising at the activities in garden and bed, such as mower cuttings. Aside all kinds of household waste, resp. kitchen waste, can be composted and changed into fertile, nutrient-rich humus soil instead of ended up onto the dump or into the incineration plant.

Raised bed

Raised-bed gardening is a form of classic  (at ground label) bed layouts or according to filling in layer structure a version of mound bed. It is mostly found in near-natural gardening. The raised bed united the following essential characteristics: elimination of stoop down when gardening by rising higher of bed; very little weed because primary seed flight  takes place at ground level; no slugs, if slug fence is fixed; use of rotting heat from below (at the roots) through in layers structure and associated with this an essential faster growth. Through additional installation of a cover, the raised bed can be used as cold frame, also. Mounting is also possible on unfavorable grounds, bedrock, even on paved courtyards and contaminated grounds.