The choice of materials and good installation are essential for the durability of screed over time. Given its importance, we decided to create this short guide to screed, and its cracking issues, to help you make an informed and long-term choice when working with it.
THE ROLE OF SCREED
Screed is a fundamentally important layer of cement which makes it possible to:
- create a level, uniform, and flat surface of a desired height that serves as a base for the actual floor;
- distribute the surface operating loads evenly;
- separate structural elements from those of finished surfaces;
- accommodate and protect plumbing and heating pipes in addition to electric cables;
- work in conjunction with the reinforced concrete structure of the floor;
- contribute to acoustic and thermal insulation through the use of specific materials.
Understandably, the correct installation of screed is fundamental for several reasons. It:
- allows perfect installation of the flooring and ensures its stability over time;
- protects installations;
- allows the correct installation and use of doors;
- allows support of furnishings due to an absence of slopes.
CRACKING IN SCREED: FREQUENT CAUSES
Screed can be subject to cracking which can affect its function. The causes of cracking in screed are many and are often linked to errors made during the laying phase. Below we have listed the most frequent ones:
- excess moisture;
- insufficient rigidity and compactness;
- excessive shrinkage of the cement mixture;
- ridges and depressions in the surface;
- incorrect mixing of the mix;
- inadequate curing;
- the presence of overlapping pipes and systems that are not correctly positioned;
- having a thickness less than that recommended in the material’s specifications;
- continuous stress over time, for example, that produced by heavy vehicle traffic.
THE ROLE OF ELECTRO-WELDED MESHES IN OBTAINING TIME-TESTED SCREED
To avoid cracking in screed, it is essential to use specialised electro-welded metal mesh which performs a double function as reinforcement and support. In fact, this mesh is able to:
- give rigidity to the screed;
- counter the different working stresses;
- protect the integrity of the screed.
Cavatorta has designed and produced three anti-cracking meshes with improved adhesion, which guarantee excellent performance over time and protect the screed. Here we describe briefly the advantages and characteristics of these three products.
METAL MESHES FOR CAVATORTA BRAND SCREED
Pavitec HP
Electro-welded mesh in hot-galvanized steel with high resistance. The mesh is marketed as panels with square-shaped links. Among the main advantages offered by this mesh are:
- Impeccable adherence
The wire features evenly distributed ribs along its surface, serving to significantly reduce sliding between the steel and the cement. - Robustness and solidity
Effectively combats cracking over time and protects the layers of compactness and strength in the screed.
Use context
Ideal for laying heated and floating floors.
Pavitec Pro
Electro-welded mesh with improved adhesion. Comes in flat sheets for floors and facades and has an anti-cracking and anti-shrinkage function. Among the main advantages offered by this mesh are:
- Corrosion resistance
The wires of this mesh are 2.00 mm in diameter and are protected with zinc coating acheived through a hot-galvanizing immersion process that increases corrosion resistance. - Resistance to stress
Contributes to increased mechanical resistance of the screed and prevents the formation of surface cracks and damage due to load impact.
Use Context
Ideal support for substrates and plasters, perfect for planar and compact foundations to which the final flooring is adhered. The use of Pavitec Pro is also useful in plastering with a thickness of application that exceeds 4 cm.
Pavitec Professional
Electro-welded steel mesh with high resistance and improved adhesion due to its special ribs which are distributed along the surface of the wire. Hot-galvanizing ensures excellent corrosion resistance over time. The diameter of the wires (2.00 mm) offers greater robustness. Among the main advantages offered by this mesh are:
- Spacing folds
Has five longitudinal folds that make the use of spacers unnecessary. Two of these are on the edges, so it will allow an overlap between adjacent panels without traditional fasteners. The other three folds are distributed evenly along the panels, allowing them to be walked on without the risk of becoming deformed.
Use context
Ideal as light reinforcement. Has an anti-cracking properties for flooring, such as tiled floors, floating floors, heated floors, pedestrian walkways, access ramps, parking areas, swimming pools, terraces, balconies, and facades.