Installation and production of fixed formwork from expanded polystyrene

In the manufacture of foundations for any construction objects, enclosing formwork is necessarily used. It defines the outlines of the concrete base, corresponding to the pouring scheme, and its exact geometric dimensions. Expanded polystyrene formwork is one of the possible options for enclosing structures, which are increasingly used in construction.

Pros and cons

The use of modern fences used in the manufacture of foundations is justified by the presence of a number of advantages:

• quick installation of the foundation due to the combination of several operations at once: load-bearing elements and high-quality thermal insulation are mounted in one technological cycle;
• profitability due to the low cost of material and the absence of costs for its dismantling;
• the possibility of obtaining a flat surface of the walls of the foundation being erected, which reduces the consumption of concrete mortar;
• increasing the strength and reliability of the structure due to the fact that the fixed formwork made of expanded polystyrene becomes part of the foundation;
• the tightness of the enclosing structure, which excludes the leakage of water and concrete mixture, is achieved due to the high density of installation of the slabs;
• protection of structural elements from adverse environmental influences and biostability, which extend the life of the structure.

The use of fences based on PSP allows you to protect the foundation from frozen soil, low thermal conductivity (only 0.032 W / m) significantly reduces heat loss. The advantages of expanded polystyrene formwork for the foundation include the possibility of obtaining a closed contour of the fence, due to this it is possible to reduce losses by another 11 percent. At the same time, the cost of fixed formwork in comparison with standard structures is about 20 percent lower.

The disadvantages of such structures include:

• exposure of foam to ultraviolet radiation;
• significant time costs for the arrangement of a separate waterproofing (especially for formwork) and for the stage-by-stage pouring of the concrete mixture;
• the need to reinforce products made of EPS with transverse reinforcement.

The disadvantage of using this material is considered to be insufficient thermal insulation of the lower layers of the poured foundation.

Formwork types

Before starting installation work, it is advisable to familiarize yourself with the existing options for fixed fences used in construction practice. The main feature by which products are classified is the material of manufacture:

• expanded polystyrene;
• fibrolite;
• arbolite.

The choice of a suitable option is determined by the complexity of the future construction and its design features. Gas-filled foam stands out among its peers for its strength and lightness. When installing it, there is no need to involve heavy construction equipment.

Fibrolite is made on the basis of two components:

• wood shavings, giving the formwork elements a characteristic fiber;
• an inorganic binder responsible for fiber adhesion and material strength.

The main advantage of fiberboard formwork is resistance to temperature fluctuations.

Arbolite includes two components: wood chips and concrete mixture, which, when mixed, are formed in the form of blocks of a given shape. In the latter, small voids are provided, which are reinforced with fittings during installation, and then filled with mortar. Despite the attractive strength indicators, wood concrete products have a number of disadvantages, including low thermal insulation and high cost.

You should also pay attention to a mixture of wood chips with concrete or wood chips, which stands out for its excellent soundproofing properties.

According to the features of the structure formed by the elements of the fences, the known types of fixed formwork made of PPP are:

• cellular;
• classic;
• modernized.

The first type is a set of hollow blocks, fastened together like a children's prefabricated constructor. The resulting cavities provide free filling of the inner spaces of the formwork with the solution. For the reinforcement of the fill, vertical and horizontal elements are used that are attached inside the PPP cells. Such blocks are usually manufactured on an industrial scale.

Classic designs are presented in the form of customary shield fences installed on both sides of the flooded space. Between themselves, the PPS plates are additionally connected with metal ties. The improved fences practically repeat the previous version, but instead of typical metal screeds, they use metal or wood beams. To increase the strength of the structure, they also use struts and stops.

Installation features for strip foundations

Strip foundations are among the most popular foundations built by self-erecting houses and other structures. In their manufacture, the preparation of the pouring point takes on particular importance, since the reliability of the entire structure depends on its quality. The formwork for the strip foundation made of expanded polystyrene is arranged quite simply, which does not exclude the need to take into account the following nuances:

• it is recommended to pour the solution into such a structure in layers, which guarantees a smooth increase in the load on the walls;
• cavities in the block are filled with mortar according to the same technique as the main foundation mass;
• the reinforcement used to strengthen the foundation is laid in such a way as not to damage the working surfaces;
• strapping is usually performed inside block elements;
• there is no need to dismantle the PPP slabs, since they remain in the structure as thermal insulation elements.

If necessary, the fixed formwork made of expanded polystyrene is additionally strengthened by means of spacers. At the same time, it is important to preserve the configuration of the foundation found in the project unchanged.

Do-it-yourself fixed formwork

For self-arrangement of a PPP fence for foundations of any type, you will need to familiarize yourself with the order of the operations performed during this. Due to the lightness of the material used, all procedures for its arrangement are carried out by one person without outside help. The declared advantages of products based on PPP allow you to act as follows:

1. A sketch of the strip foundation is drawn up with an exact indication of the location of the individual elements.
2. The blanks of the proprietary PPS formwork are being prepared. When choosing them, the need to use several rows of structures (up to 4) is taken into account.
3. Measures are being taken to tie the formwork elements to the poured space, for which pieces of reinforcement of a small diameter are used.
4. During the installation of non-removable structures based on PPS, special attention is paid to the density of their joining - no gaps should remain.
5. When carrying out installation work, do not pour all the concrete at once.First, a partial pouring is carried out, after which a pause is made for 3-4 hours, sufficient for the mortar to shrink. After that, the remaining volume of the concrete mixture is added.

When constructing monolithic foundations, special molded shields are used for casting fences. The individual components are connected by means of tie bolts and form a working area, which is then poured with concrete. When working with them, it must be taken into account that these products have different dimensions.

What attention is paid to

When working with foam blanks, it is recommended to pay attention to the following features of the formwork arrangement:

• the height of removable block structures is on average 3.3 meters;
• width ranges from 0.25 to 2.4 meters;
• the exact dimensions of the block formwork are selected based on the individual characteristics of a particular structure;
• the foundation also needs a phased fill, which is explained by the instability of the enclosing structure.

Even with a four-row stacking of blocks using reinforcing reinforcement, the pouring requires pauses between several approaches. This time is enough for the solution to completely settle and compact well.

When installing non-removable blocks made of expanded polystyrene, much attention is paid to the area of ​​their docking. The individual elements of the branched foam structure are interconnected with special care, which allows you to get the most even pouring surface.