Magnesia screed

In addition to the widely used cement and calcium sulphate screeds, there are specialists for special tasks. These include magnesia screed (MA), historically also known as stone wood screed. Although it is used less frequently today, this magnesium oxide-based mineral screed offers unique properties that predestine it for certain niche applications in industry and commerce. As your experienced experts for screed systems, operating throughout Germany, we know the specific advantages, but also the critical application limits of magnesia screed and can advise you on whether it is the right choice for your project.

What is magnesia screed (MA)? A look at the composition

In contrast to other mineral screeds, magnesia screed is not based on cement or gypsum, but on a special binder:

• Binder: Caustically fired magnesite (magnesium oxide, MgO) is mixed with a magnesium chloride or magnesium sulphate solution. These react chemically and harden to form a solid magnesium oxychloride or magnesium sulphate cement.
• Fillers: In addition to aggregates, organic fillers such as wood flour or sawdust can also be included (hence the old name "stonewood screed"), or inorganic fillers to control properties.

This special chemistry gives it its specific properties.

Specific advantages: When magnesia screed scores

Magnesia screed is not an all-rounder, but in certain situations it offers clear advantages:

1. Electrical conductivity / antistatic: MA screed is conductive or antistatic by nature. This makes it ideal for areas where electrostatic charges must be avoided (ESD protection).
2. Non-sparking: With suitable additives, it can be adjusted to be non-sparking - a decisive criterion for use in potentially explosive areas (EX zones).
3. Resistance to oils & solvents: It is resistant to many mineral oils, greases and solvents, which qualifies it for certain workshops. Keyword: oil-resistant.
4. High early strength: It achieves high strength relatively quickly after installation.
5. Low layer thicknesses: Often allows lower construction heights than cement screed with good strength.
6. "Warm" feeling (stone wood): Variants with wood fillers feel warmer than purely mineral screeds.
7. Sandable: Can be sanded to an attractive, terazzo-like surface.

The decisive weak point: extreme sensitivity to moisture!

This is the most important point and the biggest limitation of magnesia screed: it is extremely sensitive to moisture and wetness!

• No moisture: Permanent or repeated exposure to water or high humidity leads to softening, swelling, efflorescence and loss of strength or even destruction.
• Risk of corrosion: With chloride-containing binders, moisture can lead to corrosion of embedded metal parts (e.g. pipes).
• Area of application: Magnesia screed is therefore only suitable for permanently dry indoor areas. Outdoor areas, wet rooms, areas with frequent wet cleaning or with a risk of rising damp from below are absolutely taboo! A functioning moisture barrier in the substrate is mandatory.

Expert warning: Moisture sensitivity is the main reason why MA screed is used less frequently today and requires very careful planning and suitability testing.

Areas of application: Niches for a specialist

Due to its properties, the use of magnesia screed today is concentrated on special industrial screed applications:

• EX-protected zones in industry (chemical warehouses, paint shops, etc.).
• Areas with requirements for conductive or antistatic floors (electronics production, laboratories, operating theaters - synthetic resin is often an alternative here).
• Certain workshops with high exposure to oils or solvents.
• Renovation and addition of historic stone wood screed floors in old buildings.
• Rare as a design floor due to its special appearance after sanding.

Laying & post-treatment: Special features of MA screed

The processing of magnesia screed requires specific knowledge:

• Correct dosing of the components (magnesium oxide and salt solution).
• Installation in conventional, earth-moist consistency (spreading, stripping, compacting, smoothing).
• Ensure absolutely dry ambient and substrate conditions.
• Need for suitable surface treatment (sealing, coating) to protect against abrasion and short-term exposure to moisture.

Costs for magnesia screed: classification

Magnesia screed is generally more expensive than standard cement screed due to the special binders and the often more demanding processing. The costs must be calculated on a project-specific basis. A detailed quotation is required.

Your partner for magnesia screed? Our expertise

We have the necessary expertise for the rare but demanding application of magnesia screed:

• Knowledge of materials: We know the properties and critical limits of MA.
• Application advice: We check exactly whether MA is suitable for your purpose or whether modern alternatives (e.g. conductive synthetic resin screeds) make more sense.
• Professional execution: Ensure correct processing while taking moisture sensitivity into account.
• Nationwide service: We are also your partner throughout Germany for this special application.

Conclusion: Magnesia screed - a specialist for dry indoor areas with special requirements

Magnesia screed (MA) is not an all-round screed, but a special solution with unique advantages such as conductivity, non-sparking and oil resistance. However, its extreme sensitivity to moisture limits its use strictly to dry interior areas and requires the utmost care in planning and execution.

Special screed needed? Ask the experts!

Do you have an application where the special properties of magnesia screed could be in demand? Contact us for expert testing and advice on possible screed solutions for your project - nationwide. We are available by phone, email or WhatsApp.