Faq
Do the buildings built with ICF REXwall comply with the new Italian regulations (Legislative Decree 311/06)?
The transmittance values of the ICF REXwall walls depend on the exterior EPS thickness, varying from 0,235 W / m² K up to a value of 0.134 W / mqK. As you can see, these values are far higher than the minimum required by the Italian Legislative Decree 311/06.
For any further information see: Technical features
May problems of moisture and mold occur with ICF REXwall?
The EPS which constitutes the ICF REXwall panels consists of approximately 96-99% of air, closed in cells whose dimensions guarantee a barrier against humidity, at the same time allowing the passage of the water vapor. In virtue of this EPS property, you will never have problems of moisture or mold.
For any further information see: Technical features
How do you choose the right thickness of polystyrene?
The choice of the right thickness of polystyrene depends on two parameters:
– the degree of thermal insulation that you want to obtain, is expressed by the value of transmittance of the wall;
– the hygrometric behavior of the wall must be analyzed with the aid of a Glaser diagram, to check the possible formation of condensation inside the wall. These variables will be considered depending on the climatic zone in which the building will be built, and so taking into account all the characteristics of the specific area. A greater thickness of insulation is usually oriented outwards, so that the concrete wall is more isolated on this side, thereby preventing the formation of condensation inside the masonry.
For any further information see: Technical features
Would you suggest to use ICF REXwall also in places where temperatures can be very low?
ICF REXwall system guarantees an optimal thermal insulation, thanks to the transmittance values of EPS, that are way better compared with traditional building materials. With ICF REXwall system, heat losses in the buildings during winter are reduced. In this way the temperature inside heated buildings maintains itself constant for the benefit of the residents: the consequence is a greater energy efficiency of the building, with consequent savings, in monetary terms. Just think that ICF REXwall, with all the possible panel combinations, is also used for the insulation of cold storages (in the maximum conformation of 18 +18).
For any further information see: Technical features
Why polystyrene is used as insulating material?
Expanded Polystyrene is famous for its thermal insulation qualities and for being a moisture barrier, thanks to its closed-cell structure, that holds the air within itself (Expanded Polystyrene is made for 98% of air), impeding any convective air motion and thereby conferring its excellent thermal-insulation properties. The EPS, which constitutes the ICF RexWall blocks, is also subjected to the sintering process, phase in which the Expanded Polystyrene beads, under the action of water vapor, weld together in a homogeneous block of expanded material. In addition, in the construction industry the use of EPS is recommended because, having no nutritional value, no fungi, bacteria or other micro-organisms can live there. Moreover, its properties remain constant in time: no research has proved this to be wrong so far.
Is EPS a fuel?
EPS, which consists of carbon and hydrogen, is a fuel by its nature, as well as other products of plant origin. It ignites at about 450°C, and the flame then propagates spontaneously if there’s a sufficient amount of oxygen. However, in the construction industry is used a particular type of self-extinguishing flame retardant EPS. The extinguishment is simple and fast. During combustion are produced 50 ppm of styrene (as the maximum limit) and only 1000 ppm of carbon monoxide, that is considerably less than the 69000 ppm produced with the combustion of wood-fiber and similar products, and the 29000 ppm produced by cork. Furthermore, EPS combustion causes the production of 60 ppm of styrene and aromatics in total, while wood and cork can produce 1000 ppm.
For any further information see: System features
ICF REXwall combines concrete casting and insulation in a single process. Which are the benefits?
The most remarkable advantage derived from the use of ICF REXwall is the presence of the insulation layer even in the internal face of the masonry. Thanks to this, who lives in the area delimited by walls, is in direct contact with the insulating surface that is perceived as “hot” and capable of giving a pleasant feeling of comfort.
For any further information see: Benefits of the system
Is the acoustic insulation provided by ICF REXwall walls good?
The acoustic insulation level that can be achieved using ICF REXwall system, guarantees values higher than those required by the Italian law (see “Determination of passive acoustic requirements of buildings”). Considering a partition wall separating the housing units, built with ICF REXwall blocks (thickness 7 +10 +7) to which is applied a plasterboard panel on both sides, we obtain a value of acoustic resistance R’w of 50 dB: the minimum required by law is a R’w value of 50 dB. For exterior walls built with the ICF REXwall block (thickness 7 +15 +7) we apply an internal plasterboard panel and an external double shaving, whose acoustic resistance value R’w is 51.
For any further information see: Technical features
Which type of concrete is recommended for the casting process?
The concrete for the casting operations must belong to the resistance class RCK and to the consistency class S4, defined by the building project. The grain size of inert materials must have a maximum diameter of 20 mm. The concrete slump values mustn’t exceed 170-180 mm. It is absolutely not recommended to add retardants and plasticizers to the mixture.
For any further information see: Technical details of sites
Can ICF REXwall be used also in areas with a high seismic risk?
With ICF REXwall can be built concrete walls with distributed reinforcement (SAAD). The system is based on the use of permanent EPS formworks that, assembled together, compose a structure able to receive the concrete flow. The spacers that join the panels composing the ICF REXwall blocks have areas where to insert the horizontal reinforcing bars; these bars need to be integrated with an appropriate vertical reinforcement. In this way it’s possible to create monolithic reinforced concrete structures for anti-seismic buildings.
For any further information see: System features
Can the system be used for the construction of underground walls?
ICF REXwall system is perfect for the construction of underground walls as, in this case, can be performed a “flush” casting (when the excavation can be done with a vertical wall), without removing the formworks to dismantle. In addition all can be done quickly and easily, without the need for major equipment. If ground water is present or if the ground is particularly rich in water (especially at the foundations level), we adopt the waterproofing ICF REXwall walls with adhesive membranes or special spreadable materials. Moreover, the ICF REXwall system is excellent for building underground walls, thanks to the fact that the EPS (Expanded Polystyrene) that is the core of the system, has excellent insulating properties, and protects the concrete structure from the contact with the ground. Finally, a particular anti-root layer has to be placed to avoid that the insulating layer is damaged by the roots of trees.
Will the concrete cast inside the ICF Rexwall have problems during the hardening process? Will it be able to reach the required levels of resistance?
The “Portland Cement Association”, a worldwide leader organization specialized in monitoring the progresses made by the concrete technology, showed that if the concrete sits in a moist environment, such as in the case of in the ICF REXwall concrete, it reaches a compressive strength that goes well beyond 50% of the strength of the concrete removed from formworks after 2 days (as normally occurs using a traditional formwork system). Just think that the majority of samples used to test the concrete strength, are developed inside special EPS boxes.
Do I need qualified manpower to build with the ICF REXwall system?
For the construction of buildings with ICF RexWall system is not required qualified manpower. The system has been studied so as to allow the correct construction of the wall easily. In the case of mistakes during the building process, the blocks will no longer slot in already at the third row, and won’t be possible to continue further with the installation. Moreover, building with ICF REXwall is safe and it is not an arduous work because each standard panel weighs at most only 2 kg. Rexpolgroup also guarantees a training service and the technical assistance of our skilled experts at the construction site, in order to avoid unnecessary installation errors.
For any further information see: Technical services
How do we place the plants?
The installers, using a hot knife, can independently create the tracks for the plants on the blocks in a safe, fast and non-destructive way. In fact, the internal thickness of 7 cm makes possible the creation of the tracks and the positioning of the junction boxes.
For any further information see: Plants
How do we make air holes and vents for the drains?
The placement of air holes must be established during the designing stage. Holes must be created for the openings at ground level; when the first row of ICF REXwall elements has been installed, the other openings can be created before the casting phase, using a saw suitable for cutting the blocks, then positioning the pipes and the sleeves and finally covering the possible discrepancies using a polyurethane foam. It is important to remember to protect these parts before and during the casting process.
For any further information see: Technical details of sites
How can be applied the internal finishes?
ICF REXwall is geared with a structure appositely designed for the installation of plasterboard panels. The internal finishes can be fastened (using self-threading screws) directly to the brackets on the internal surface of the block (placed at a distance of 20 cm from each other). The installation of the coating directly on the ICF REXwall wall avoids the construction of a further special structure where to apply the finishes.
For any further information see: Finishes
How do we complete the external finish?
The external finish can well be the one used in the traditional coating systems, created with a cement-based shaving on a fiberglass net. Alternatively, on the metal net can be applied traditional plaster, or any other type of coating such as “fake bricks” or stones, glued directly onto the polystyrene wall.
For any further information see: Finishes
Is a special equipment required to build structures with ICF REXwall?
No, you do not need special equipment to build structures with ICF REXwall, but just standard tools such as saws, screwdrivers, hammers and wooden scantlings to maintain the correct alignment of the formworks.
For any further information see: Installation phases
How are made the “T” junctions between the ICF REXwall walls?
There are different types of junction, depending on if the wall is composed by blocks of equal thickness, or blocks with different thicknesses. In both cases, to create the junction, the procedure is the following:
– make a cut on the panel of the block facing the intersecting wall. This cut must equalize (in measure) the thickness of the block that will constitute the intersection wall;
– create the intersection, join and tie together the blocks through the brackets, then proceed with the application of the foam and seal the points of intersection;
– apply props to stabilize and support the containment of the concrete during the casting process.
For any further information see: Technical details of sites
Do closure elements, suitable for ICF REXwall walls, exist?
Yes, these EPS elements are available in various sizes, according to the type of wall that you own. These elements, customized by Rexpolgroup, have the function of completing the thermal insulation at the openings (doors and windows) and can be used also as closing elements of the masonry.
These slabs of variable size are inserted inside the ICF RexWall masonry and anchored on the wooden boards, in order to seal the openings.
For any further information see: Technical details of sites
How can I reach the height of the floor slab?
The EPS Jolly Pannel (120 cm of length) can be proportionately cut in order to exactly stop at the height of the floor slab. The heights required by the project, can be reached simply cutting the ICF REXwall blocks horizontally (when the height of the masonry is not a measure multiple of 35 cm).
How can be installed the counterframes?
The first row of blocks has to be placed until the height of the window is reached, then a wooden counterframe with the same thickness of the concrete must be installed. Continuing with the laying, the blocks must be placed and leaned against the counterframe, cutting off the excess. Later, a polyurethane foam can be used to fix the counterframes, fastening them with wooden boards in the designated brackets, using clamps and props to support the vertical openings during the casting process.
For any further information see: Technical details of sites
Can we create curved walls with the ICF REXwall system?
With ICF REXwall it is possible to create curved walls too. Once known the radius of curvature, you can proceed with the cut of the linear blocks using a ripsaw, thus obtaining the segments, which will be joined together to form the curved blocks of required radius. These blocks will be supplied ready to be mounted and they will be able to receive the concrete flow.
Is it possible to build pools using the ICF REXwall system?
ICF REXwall system is excellent to create pools because the EPS of the formworks has optimal insulating properties (see the question about the construction of underground walls with ICF RexWall) so that the concrete structure is well protected. In addition, the perimetral walls of the pool can be built quickly and easily, without removing the formworks and without using major equipment. The exceptional thermal transmittance of the panels provides hot water for 30 days longer than how a normal in-ground pool does.
What kind of finishes are suitable for the exteriors?
With ICF RexWall it’s possible to create all types of external finishes. The external walls are suitable for the application of any kind of plaster normally used as coating: you can choose to create a cement-based plaster, consisting of a double shaving with a fiberglass net (coating thickness of 7 mm), or a thicker plaster. In this case it will be geared with a metal net for the plaster. Alternatively it can also be created a stone covering, (natural stone, synthetic stone, assembled stone…) or can be used fake bricks, tiles (stoneware, ceramics…) by applying coating materials on the ICF REXwall blocks using a layer of special glue or cement mortar.
For any further information see: Finishes
What kind of finishes can be used for the interiors?
The ideal finish for the interiors is plasterboard, thanks to the possibility of fastening the covering slabs directly to the internal tracks inside each Jolly Pannel, with no need for traditional pillars. Once the plasterboard slabs are fastened, it’s possible to apply special joint coverings and then grout them in order to make the surface homogeneous. We can also make plaster finishes of various thicknesses using multiple layers of cement plaster, or using the spray technique, or again applying coatings such as tiles, bricks or technical stone, fixing the coating materials to the blocks with a layer of a specific glue or of adhesive mortar.
For any further information see: Finishes
