FAQ – facades

We are planning to build a family home. Can you recommend us the best combination of base construction material for external walls with your insulating plaster so that it meets the required parameters for the Green Savings Fund grant?

  • Porotherm blocks with recommended thickness of 44 cm, our interior plaster with a maximum thickness of 1 cm and the facade layer with a minimum thickness of 2 cm.
  • Gas silicate Ytong blocks thickness at least 30 cm and a 2.5 cm layer of our plaster on the exterior facade.
  • For the surface treatment of walls, a 2-4 mm layer of internal stucco is sufficient for maintaining the air permeability and thermal insulation properties of the construction materials

What are the advantages of your products over expanded polystyrene?

  • Lower purchasing costs as a result of cheaper materials and a significantly shorter time for rendering facades (cost savings on labour, equipment, scaffolding etc.) – a regular sized house and complexity of façade takes about 6-8 days to complete
  • Acquire an environment-friendly coat for your house, one that is resistant to weathering, biological and mechanical damage, has a long life and is easy to maintain
  • Insulation without thermal bridges and therefore without the resulting thermal loss
  • Preserving the air permeability of your house, eliminating damp in the walls and preventing the emergence of bacterial mould in the house
  • By choosing the right combination of masonry, facade material and interior plaster, you can reduce exterior wall thickness and thereby lighten the building structure and reduce the cost of constructing a new building (fig 54, 53)

In simple terms, can you clearly compare the advantages and disadvantages of your plaster with expanded polystyrene and mineral wool insulation?

    • We have compiled the following table in which we compared the characteristics and parameters of our product with commonly used insulation systems using expanded polystyrene and mineral wool, without overwhelming you with too much technical data or calculations.

    Comparative table: “+” means better properties, “-” means worse properties

      Expanded polystyrene Mineral wool MultiSAN
    Strength

    –

    –

    +
    Durability

    –

    –

    +
    Resistance to fire

    –

    –

    +
    Resistance to freezing

    –

    –

    +
    Environment friendly

    –

    –

    +
    Ease of application

    –

    –

    +
    Versatility

    –

    –

    +
    Thermal loss prevention

    –

    –

    +
    Hydrophobic

    –

    –

    +
    Vapour repellence

    –

    +

    +
    Stability

    –

    –

    +
    Thermal conductivity (ƛ)

    +

    +

    +
    Pest resistance

    –

    –

    +
    Water absorption

    +

    –

    +
    Shock development

    –

    –

    +
    Water vapour

    +

    +

    +
    Price

    +

    –

    +

I’ve had a bad experience with the surface treatment of my EPS external wall insulation. It is fragile and not very resistant to impact. What is the impact resistance and lifespan of Multisan Xtra?

  • With our facade there is absolutely no risk of mechanical damage caused by a hard impact from a ball, falling bicycle or any other object.
  • Our facade will definitely not be chewed up by your dog or have holes dug in it by your child with her sand-pit spade.
  • Unlike many component insulation systems which also include polystyrene, our insulation consists of only a single material, which means resistance to mechanical damage is substantially higher.
  • Nor does it provide suitable conditions for nesting insects, birds or rodents.
  • The durability of the material has been tested in so-called freezing cycles – in layman’s terms this test specifies the number of winter frosts the material can survive without any change in properties. Our material has successfully passed a test of 50 cycles, although the data we present states only the statutory minimum of 25 freezing cycles.

Can you approximately quantify the cost savings when renovating an old rural house using your plaster?

  • On older and especially rural houses and farms, a range of construction materials were often combined, especially during successive extensions to a property.
  • We have therefore compiled a table of the most common basic masonry materials used in construction – both in the past and today.
  • The above percentages are purely indicative since providing accurate figures for an old building would depend entirely on the specific materials and their condition.
  • However, the more the walls in your house are damaged, weathered or waterlogged, the more the thermal insulating and renovating properties of our plaster will manifest themselves.

Is it necessary to remove old Czech Brizolit plaster to the bare brick before using Multisan Xtra?

  • Certainly not. It is sufficient to remove plaster in those places where it has deteriorated, loosened from the underlying surface or has fallen off altogether.
  • Should a significant surface irregularity be created by removing old plaster, it can be filled with core plaster.
  • It is sufficient to simply sweep over the original Brizolit plaster, clean it with a high-pressure washer and it is ready for applying Multisan Xtra.
  • Our material connects perfectly with Brizolit due to its excellent adhesive properties. It seeps through and thoroughly solidifies the entire Brizolit facade.
  • You will not only save a lot of time and work with keeping bits of the original facade, but also the costs associated with debris clean-up and removal.

Can I achieve a final surface treatment using Multisan Xtra plaster on my facade, or is it necessary to apply an additional finishing layer?

  • Work with the Multisan Xtra plaster is very simple.
  • All our products are available for home use, there is no need to be a professional plasterer. Using them is the ordinary plastering work our grandfathers used to do.
  • So if you have basic experience with plastering and you are a typically skilled DIY enthusiast, you need only read our simple manual and get to work.

Can an ordinary DIY expert work with your plasters by him- or herself?

  • Lower purchasing costs as a result of cheaper materials and a significantly shorter time for rendering facades (cost savings on labour, equipment, scaffolding etc.) – a regular sized house and complexity of façade takes about 6-8 days to complete
  • Acquire an environment-friendly coat for your house, one that is resistant to weathering, biological and mechanical damage, has a long life and is easy to maintain
  • Insulation without thermal bridges and therefore without the resulting thermal loss
  • Preserving the air permeability of your house, eliminating damp in the walls and preventing the emergence of bacterial mould in the house
  • By choosing the right combination of masonry, facade material and interior plaster, you can reduce exterior wall thickness and thereby lighten the building structure and reduce the cost of constructing a new building (fig 54, 53)

What are the differences and the advantages of your Multisan Xtra compared to the almost perfect expanded polystyrene insulating system? I would like a detailed explanation.

  • If you would like to hear a comparison specifying what thickness of our plaster can replace standard polystyrene external wall insulation, then that is a discussion we don’t want to get into.

    Why?

    It is necessary to consider a number of other significant facts which are reflected in the economic calculation and cost-effectiveness of the total cost of the investment, not to mention questions of lifespan and the problem of disposing old polystyrene. Ours is a fundamentally different approach to insulation.

    Advantages you get with our product over expanded polystyrene

    • lower purchasing costs, resulting from the lower price of materials and a significantly shorter time for the application of facades (cost savings on labour, equipment, scaffolding etc.) – a regular sized house with standard facade complexity takes about 6-8 days to complete
    • acquiring an environment-friendly coat for your house which resistant to weathering, biological and mechanical damage, has a long life and is easy to maintain
    • insulation without thermal bridges and resulting thermal loss
    • preserving the air permeability of your house, eliminating damp walls and preventing the emergence of bacterial mould in the house
    • by choosing the right combination of masonry, facade material and interior plaster you can reduce the exterior wall thickness, thereby lightening the building structure and reducing the cost of constructing a new building

FAQ – renovating against damp

Can the renovating plaster MultiSAN be used for basements?

  • In this case, the ideal solution is to uncover the foundations outside the building, restore the horizontal damp proofing in the walls and create a ventilated space from the outside, e.g. using an IPT system (Insulated Ventilated Slab). Then you can use Multisan plaster on the interior wall following normal provisions for renovating plasters. This solution, however, is demanding both in terms of implementation and cost.

    If the above solution cannot be applied, whether for technical or economic reasons, the following steps are recommended: plaster the interior wall surfaces using mortar with added crystallization waterproofing materials (e.g. Akvatron 6 or 12), which severely restricts, even stops, the penetration of water into the basement, and then apply Multisan renovating plaster onto this prepared surface. Any remaining seepage will be removed in the form of water vapour and therefore will not destroy the plaster surface and due to its properties, our plaster will additionally thermally insulate the cellar or basement. It is necessary to realize, however, that the moisture largely remains in the brickwork, which is not ideal in terms of the thermal properties of masonry. Nonetheless, this is the price paid for a quick and cheap solution to the problem of a wet basement.

How do renovating plasters work?

  • Renovating plasters combine high porosity and water vapour permeability with lowered capillarity. These are the only plasters you can apply as a measure against humidity, but should always be complemented by using other methods dehumidification. Renovating plasters are effective even at higher water salinity. Aggressive salts (chlorides, sulphates and nitrates) are stored in renovating plaster systems in the pores and not penetrate to the surface. Thus there is no destruction of the surface layers of plaster, the wall or façade looks good for many, many years and the dampness of the brickwork decreases. If the condition of the wall allows only the use of renovating plasters, this solution is in all respects very effective and favourable.

    Multisan renovating plaster is ideal for renovation work because of its unique composition, its use of natural materials and pozzolanic binders, and is very suitable for listed buildings.

What are the other masonry dehumidifying options besides renovating plasters?

    • There are numerous other possibilities. Some of the oldest methods are the so-called air methods. The basic principle of these historical measures is to increase the surface area from which water vapour can diffuse into the atmosphere. Such approaches can be improved by increasing airflow (using altitude or temperature differences). These ventilated spaces usually exist in older buildings, although they can become clogged with leaves, dirt and other debris, in which case they are no longer functional. It is therefore necessary to restore their function by cleaning. These older systems include so-called “English yards”, ventilated floors or ventilated spaces along the walls, and indeed the principle is still in use today, for example the IPT system (www.iptsystem.cz). It is also possible to use mechanical methods to replace non-functional horizontal damp proofing. Such interventions include undercutting, the insertion of stainless steel plates, or perhaps using an infusion aperture (mortar injections using chemical compositions, molten paraffin etc.). Other approaches employ electrophysiological methods based on the movement of water molecules in the electromagnetic field. Almost always it is necessary to combine these methods with renovating plaster. Combining two or more methods, however, reliably solves the problem of wet building structures.

What are the causes of damp building walls?

  • The causes can be numerous. When identifying appropriate renovation measures, it is good to consult with a specialist who has experience in renovating damp masonry.

    Generally the causes of defects can be divided into three groups:

    • Causes in the building itself, its condition and design. These include, for example, instances where the building has no damp proofing or the damp proofing is damaged, or even that it was poorly designed.
    • Causes outside the building, in the environment where it is located or in its immediate vicinity. In this group, the most common cause of damp masonry is poor drainage from the surface around the building and the surface of the building wall. Another possible cause is that the building is built on a site where the groundwater level is too high. Problems are caused by salting on roads, urea from livestock stables, etc. The salts are transported by water into the walls, increase in volume during the crystallization process and thus destroy the plaster.
    • Most often, however, the causes are combined and derive from faults both within the building and its surroundings.

I’m having trouble understanding how your plaster acts as a raincoat and protects the building in the same way…

  • Watching our “Waterproof” video will convince you that Multisan is a material which has the ability to stop water. In the test, water poured into a bowl cut into the material remains – it is neither absorbed into material nor penetrates into the joint between two pieces of plaster held together with a rubber band.
  • In practice, this means that your wall, clad in a layer of Multisan renovating mortar, will withstand any impact due to rain squalls, melting snow drifts and the like.
  • The material has the ability to let air permeate out, but stop water and moisture from coming in – characteristics which make it unique.
  • See for yourself and check out the air pump test, where air is blown through the material which is covered with water.

I have wet and mouldy walls in the basement of an old house. The rooms are partly below ground level. Will Multisan help me solve the problem? How do I prepare a substrate with mould and precipitated salts before applying the plaster?

  • It will certainly help. We have experience applying our plasters in similar conditions, and the effect is very good.
  • Multisan “exhales” moisture and over time you will find the cellars free of any signs of moisture in the masonry.
  • Prepare the substrate by mechanical cleaning (sweeping), scrape away mineralized salts with a scraper or wire brush. Because the masonry is already wet, you can apply plastered without wetting.
  • We recommended a layer of plaster about 2.5 cm thick, i.e. one bag/m2.