FAQ – Frequently Asked Questions 

Primers

  1. Why should I use a primer?

Floor screeds

  1. How long does it take for \”Széria\” to set to light foot traffic and what is the waiting time before subsequent bonding?
  2. How does an anhydrite-base floor screed differ from a cement-base floor screed?
  3. Can I use lightweight estrich in rooms with underfloor heating systems?
  4. Can I use “Széria” self-levelling floor screed for thicknesses over 15 mm?

Plasters

  1. Can Széria-Glett be used over wall heating systems?
  2. Can I use Széria-Glett applied in a single coat on thicknesses over 10 mm?
  3. Can I use Széria-Glett for plasterboard joints?
  4. Can I use skimming plaster on surfaces coated with dispersion paint?
  5. Can I apply Széria-Glett over Ytong wall surfaces?
  6. Can I apply limewash over skimming plaster?
  7. Can I apply skimming plaster over limewash?

Jointing fillers

  1. Can I use Széria-Hézagoló Jointing Filler for smoothing the surfaces of plasterboards?
  2. Is it true that extra skimming over the joints is usually not necessary when using a glass fibre joint filler compound?
  3. Is it necessary to use drywall joint tape for glass fibre enforced joint filler compound?

Plasters of paris

  1. Can I use Keramod 125 plaster of Paris for making ceramics, for example for thin-walled structures?
  2. What is the setting time of Keramod 125 plaster of Paris?

Plasterboard adhesive compound and gypsum binders

  1. How does gypsum binder differ from gypsum plaster?
  2. Can the plasterboard adhesive compound only be used for plasterboards or is it good for fixing other building components as well, such as stucco ornaments?

Mortars

  1. Can I use Széria-Vakolat mortar in thicknesses of less than 6 mm?
  2. Do I have to skim coat over Széria-Vakolat mortar?

Why should I use a primer?

Primers are formulated for bonding porous and disintegrating parts of mineral substrates, walls and floor systems, thus improving the adhesion of the surface. By closing up the pores in substrates it considerably reduces and balances the hygroscopic properties of the surface in absorbent areas, and prevents gypsum-based plasters and skimming plasters from burning out. It can be applied over mineral substrates and dispersion paints as a protective coat in interior areas.

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How long does it take for \”Széria\” to set to light foot traffic and what is the waiting time before subsequent bonding?

It depends on the thicknesses applied and on the ambient conditions (e.g. temperature, humidity), generally in about 8 hours the surface sets to light foot traffic and is ready for finishing in about 24 hours.

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How does an anhydrite-base floor screed differ from a cement-base floor screed?

The anhydrite (calcium sulphate) base floor screed has better spreading properties. In the hardening process significantly less tension occurs and remains in the finished substrate, hence the resulting surface is practically tension-free and will not crack even applied sparingly, and it is suitable for areas subject to wheel chairs in thicknesses of 2 mm and above.

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Can I use lightweight estrich in rooms with underfloor heating systems?

Yes, but the heating must not be turned on for 10 days after the application.

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Can I use “Széria” self-levelling floor screed for thicknesses over 15 mm?

Yes, it can be used for thicknesses over 15 mm if spread in a single coat, but for levelling thicknesses over 10 mm \”Széria\” lightweight estrich is more cost effective, which has the same technical properties as the self-levelling floor screed for thicknesses between 2-15 mm for a considerably lower price.

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Can Széria-Glett be used over wall heating systems?

Yes, but for highly absorbent surfaces it must be primed before skim coating in order to avoid cracks from forming.

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Can I use Széria-Glett applied in a single coat on thicknesses over 10 mm?

Theoretically yes, however, cracks are more likely to occur on surfaces of thicknesses over 10 mm if applied in a single coat. For such thicknesses Széria-Vakolat mortar in 6-40 mm thicknesses appears a more economical choice.

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Can I use Széria-Glett for plasterboard joints?

Yes, but drywall joint tape must be used in all cases.

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Can I use skimming plaster on surfaces coated with dispersion paint?

No. Film-forming substances, such as dispersion paint, must be removed before skim coating.

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Can I apply Széria-Glett over Ytong wall surfaces?

Széria-Glett works very well for plastering Ytong walls, however, the surface should be primed first.

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Can I apply limewash over skimming plaster?

Theoretically it’s possible, however, you should coat the plastered surface with a primer recommended by the manufacturer of the limewash. The primer should be used in all cases!

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Can I apply skimming plaster over limewash?

Never apply Széria-Glett over calcareous surfaces of any kind. Before plastering, sand the calcareous surface thoroughly and apply a coat of primer.

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Can I use Széria-Hézagoló Jointing Filler for smoothing the surfaces of plasterboards?

If extra hard and solid surface is required Széria-Hézagoló Jointing Filler is expressly recommended for skimming plasterboard surfaces. Under normal circumstances, however, Széria-Glett should be enough and it is also more cost effective.

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Is it true that extra skimming over the joints is usually not necessary when using a glass fibre joint filler compound?

Generally speaking yes, glass and cellulose fibre reinforced plaster contains a high percentage of alpha-plaster, which does not shrink when dry, thus the material filled into the gaps and grouts fills the space completely, and it does not shrink when it gets hard.
On the other hand, extra skimming can be spared only if no drywall joint tape had been used. Extra skimming may be necessary if drywall joint tape is used.

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Is it necessary to use drywall joint tape for glass fibre enforced joint filler compound?

Not necessarily if the support structure of the plasterboard walls meet static requirements, and if the manufacturer’s instructions for the hanging of plasterboards are duly observed. Special attention should paid to making sure that the boards are properly aligned, to adequate support, screwing, and the quality of trimming and smoothing of the edges where the boards are cut or split.

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Can I use Keramod 125 plaster of Paris for making ceramics, for example for thin-walled structures?

Keramod 125 plaster of Paris can be used for making a wide range of ceramics. To complement its broad spectrum of uses we also recommend our casting plaster products for use besides Keramod 125, which provide an ideal solution for every need in ceramics production. Please consult the manufacturer or the distributor.

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What is the setting time of Keramod 125 plaster of Paris?

It does not have a specific setting time. According to MSZ 57:1977, the beginning of the setting time must be over 6 minutes, and the end of the setting time must be under 30 minutes. Naturally, if required, it can be arranged that the plaster of Paris has the same setting time within that time frame every time it is used.

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How does gypsum binder differ from gypsum plaster?

Gypsum binder is superior in every technical respect, and in quality and the structural plasters are available on the internal market. It is a fast setting (5 minutes), white binding plaster specifically formulated for installation and fastening works in various areas for building and construction, such as electrical installation. It is also suitable for repairs around the houseand for repairs before painting.

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Can the plasterboard adhesive compound only be used for plasterboards or is it good for fixing other building components as well, such as stucco ornaments?

The plasterboard adhesive compound is specially formulated drywall adhesive, which is perfectly suitable for attaching plasterboards, gypsum fibre boards (fermacell) and other gypsum boards to solid surfaces. However, it is not recommended for fixing stucco ornaments. For fixing stucco ornaments we have another gypsum-bearing product specifically formulated for that purpose. If interested, please contact our customer service.

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Can I use Széria-Vakolat mortar in thicknesses of less than 6 mm?

No, because in thicknesses below 6 mm cracks are more likely to form.

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Do I have to skim coat over Széria-Vakolat mortar?

Széria-Vakolat mortar can also be used as a skimming plaster. In that case it is usually not necessary to skim coat the surface, since it can be painted or wallpapered without skim coating if done properly.

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