Anhydrite screed or cement screed? Prices, dry times & Co
- Anhydrite and cement screed in comparison
- Tough: Cement screed
- Warm and elastic - anhydrite screed
- Anhydrite screed and cement screed mix "> prices
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The screed is a leveling layer approx. Five centimeters thick that is applied directly or indirectly to the unfinished floor. As a building material the user gypsum or cement are available. Both screed types have their advantages and disadvantages. Read in this text everything you need to know about the individual screed types.
What does a screed have to do?
The main task of a screed is to compensate for uneven floors. Therefore, each screed is a very fine-grained raw mass, but hardens to a solid surface. Screed is easy to work on. It can be installed with simple tools and almost always succeeds.
If it's really just about getting a rough and humped concrete floor smooth, just a simple cement-sand mortar. This is ideal, for example, as a base in a garage. The floor is beautifully smooth and can be kept as desired or further coated. This applied directly to the raw concrete construction method of a screed is unsuitable for residential buildings, however.
Sound insulation by floating screed
In residential and especially in apartment buildings, a special form of screed has prevailed. This type of screed does not differ in material, but in the structure to the simple garage screeds: The so-called floating screed is not applied directly to the concrete. Between the screed layer and the concrete floor, a thin insulation layer is installed. Mostly this layer consists of styrofoam or styrodur. However, alternative fiber-based materials are also available.
Tip: Process as little polystyrene as possible in your home or completely dispense with it. The cost of disposal has exploded in recent months. You prevent a massive loss of value in your house, if you do without the use of polystyrene.
The insulation layer between screed and concrete floor causes the impact sound to be interrupted. Without impact sound insulation, every noise on the floor passes through the whole house. This can be extremely annoying, especially for tenants who live there. Floating screed is simply standard today. He is very easy to implement. Although its processing requires a lot of care. The screed must not touch the floor or the walls directly at any point. With some expertise and conscientiousness, the floating screed is hardly more expensive than a simple leveling layer.
Warm feet through the underfloor heating
A floor heating is a wonderful comfort feature, which significantly increases the feel-good climate in a house. The systems are quite inexpensive today and easy to install. It is important in this context to know that both anhydrite screed and cement screed are suitable for installation on underfloor heating. In both cases, however, the screed raw material must be mixed extremely thin so that it really completely encloses the tubes. Flowable screed always means a high water . And this is exactly where the serious differences between anhydrite screed and cement screed begin.
Anhydrite and cement screed in comparison
Tough: Cement screed
Cement screed is basically nothing more than a fine mixture of cement and sand. Often, the very fine quartz sand is used to mix cement screed. Absolutely necessary that is not. Already with normal Bausand you get mostly adequate screeds out. You can mix the screed with the mixture 1: 4 (one part cement, four parts sand). The big advantage of cement screed is therefore that you can prefabricate the screed raw material in any consistency.
The disadvantage of cement screed is that it takes a very long time to set. This is all the more serious when it is needed as cover for a floor heating. Here it is very important to distinguish "drying" from "setting": Dried a cement screed is quite fast. However, the chemical reaction process continues inside the mass: the concrete grains burst when in contact with water and form long, crimped threads. These threads get caught up in each other. This results in the enormous strength of all products with mortar: plaster, mortar, concrete and just screed with cement are the hardest and most resistant representatives of their respective guild.
It was also common because of the long drying processes just a few years ago to mix cement screed only earth-moist and bring in a lot of manual labor in a room, deduct, rub and smooth. In the course of increased costs for craftsmen, this method is hardly used. Today the liquid floating screed is standard. Anhydrite screed is not a problem either. However, liquid cement screed takes a particularly long time to be reliably assignable. Only after 28 days the screed has set so far that it can be provided with floor coverings. Until then, he must not be covered so that he can "breathe" unhindered. If it is covered too soon, it will promote a mold under the surface.
The hardness of the cement screed is very helpful for high-strength coatings. However, it also has a drawback: The screed tends to crack. For this reason, the incorporation of a reinforcing fabric is useful for larger surfaces. A thin mesh of galvanized wire is already sufficient to safely dissipate the resulting stresses in the screed.
A particular advantage of cement screed, however, is its insensitivity to water. It is so resistant to moisture penetration that it can be used outdoors. As a leveling layer in garages, carports or as a tile floor for terraces, it is therefore ideally suited.
Warm and elastic - anhydrite screed
The bulky word "anhydrite" hides nothing but simple plaster. As with plaster, anhydrite is so popular because of its ease of processing. This also distinguishes the anhydrite screed: it is extremely easy to install. Anhydrite screed can only be mixed as a liquid screed. Then it is simply poured out and distributed a bit. The screed raw mass does the rest by itself: It compensates itself and penetrates even the smallest cracks.
The anhydrite screed is therefore especially popular with professional house builders: it is quickly installed and completely dried within a few days. The four-week waiting therefore does not apply to this type of screed. The drying can also be accelerated easily by underfloor heating. The anhydrite screed does not crack as easily as the cement screed.
A huge problem with anhydrite screed, however, is its moisture sensitivity . It absorbs invading moisture like a sponge. If this moisture is not removed quickly enough, the screed begins to rot and dissolve. The compressive strength is immediately lowered strongly in wet anhydrite screed. Therefore he is not suitable for the bath. Likewise, he is simply not applicable in the outdoor area.
Anhydrite screed and cement screed mix ">
Cost of cement or anhydrite screed
A sack of liquid screed based on anhydrite costs about 9 euros in a 40 kilogram sack . That's enough for about 2 square meters of liquid screed one centimeter thick. Higher structures need more material.
A sack of cement screed costs almost the same and is equally productive. 20 kilograms of screed are enough for one square meter at one centimeter thickness. For underfloor heating must be expected with about 3-4 centimeters thick.
Do it yourself or have it done?
The installation of screed is not too difficult, but very dirty. The screed is stirred in a pan or pumped by a pump from a silo into the rooms.
When processing screed, however, attention must be paid to eye protection. Especially cement is very dangerous for the eyesight. If in contact with eyes, rinse thoroughly immediately and consult a doctor. Wearing safety goggles avoids this danger as much as possible.
Here you can learn more about screed, how to lay it exactly, grind it and what varieties there are:
- Drying times of screed
- Grind screed
- Lay screed
- Information about quick screed
- Prices and information about screed