«Dry» technology of warming of facade

«Dry» technology of warming of facade

In the first part of article about warming of the house we have considered the general principles of heat insulation of buildings, have told why it is necessary to heat-insulate the house outside and have stated good reasons on which it is impossible to save on heater thickness. We have made the overview of “wet” method of the warming providing application of the production processes connected using cement mixes.

At obvious advantages the “wet” technology (or the plaster warmed facade) has also number of restrictions and shortcomings:

  • it cannot be applied to wooden buildings and it is irrational to use for frame;
  • works can be performed only in the conditions of steady long outside temperature from 5 to 25ºС;
  • high duration and labor input of works;
  • the wall surface has to be carefully prepared: it is leveled, cleaned from pollution, strengthened if necessary.

The “dry” technology of warming of facade is deprived of the majority of shortcomings inherent in “wet” method and is universal.

“Dry” technology

Sukhoi method of warming assumes outside covering of the building constructional framework in intervals between which elements place heater. Vapor-permeable heater is closed wind-shelter (diffusion) membrane. The framework is sheathed finishing finishing material. As a rule, between covering and heater leave air gap. The systems of warming executed by “dry” method and having the aired layer are called “the ventilated facade”.

By means of framework it is simple to hide serious defects of walls, there is no need to carry out their cleaning. Warming can be carried out at all seasons of the year, irrespective of weather patterns. Does not make problems step-by-step work that is not always possible when using “wet” technologies.

The structure of Sukhoi of the system of outside heat insulation of the house does not demand availability of high qualification and the expensive tool. The handy house master having skill of handling of the joiner’s tool can quite make warming of the house or giving independently, the hands.

Easy and heavy Sukhoi facade

Methods of heat insulation of buildings without application of wet-mix production processes are subdivided into “easy” and “heavy”. The difference in these technologies is reflected by their names.

  • The “easy” method of warming is characteristic use of the finishing materials having small weight. As a rule, it is large-size panels or boards. Fix them to framework hardware, fasten or beat. In the “easy” way warm buildings of any types.
  • The “heavy” method provides use of finishing materials of big weight: stone or ceramic granite plates. To durability of framework high requirements are imposed, it has to maintain very considerable weight. Elements of facing hang on special brackets. As the “heavy” system transfers load of building walls, this method is applicable only for constructions with strong stone walls.

The main advantage of “light” technology consists in possibility of use of cheap materials. It is the most inexpensive and simple house heat insulation performed by method. “Heavy” systems allow to create more esthetic and long-lasting warmed facades. However, because of high cost, similar decisions are used only in big-budget construction.

Heaters

Application for Sukhoi of heat insulation of two popular types of heater is most justified: mineral wool or polyfoam.

  • Mineral wool — the best choice for heat insulation of external walls. It has fibrous structure, has high vapor permeability, does not burn, is not damaged by rodents. Freely passing from walls outside water vapors, allowing them “to breathe”, mineral wool is suitable for warming of any types of constructions, including frame and from whole wood. In the “dry” systems of warming of facades use, as a rule, semifixed mats with a bulk density from 80 to 150 kg/m3, democratic at the price. Occasionally in expensive “heavy” systems apply rigid mineral wool boards to increase in durability and exception of sag of material.
    It is preferable to stack heater in two layers. For the central regions the choice from semifixed plates 5 thick or at least 4 cm which are imposed at each other in framework elements will be optimum. The upper leaf shall block joint of underlying plates. When cutting mineral wool it is necessary to cut sheets the size several millimeters bigger, than it is necessary. In this case the plate will rise into place densely, without slot.
    The main problem of nonrigid mineral wool at its room in vertical designs — shrinkage over time plates down. That to avoid it, sheets fix special dish dowels “fungi” to wall. Quantity of dowels on square meter — not less than 8 pieces. It is impossible to save on fixture, especially in upper zone of leaf.
    The high vapor permeability which is the main advantage of mineral wool defines need of ventilation of fibrous heater. Therefore at dry systems using mineral wool without fail there has to be air layer 2-4 cm thick. It will provide free air current on all height of sewing.
    To protect semifixed mineral wool from blowing off and damage by wind, it is protected without fail wind-shelter membrane.
  • Polyfoam (expanded polystyrene) — the most inexpensive type of heater for heat insulation of facades. As in Sukhoi to system it is protected by sewing and is not exposed to any influences, it is enough to use the cheapest brands of low density. But expanded polystyrene has number of essential shortcomings. It is unsafe from the fire point of view though it is not so important for exterior finish. In it like to gnaw through mouse holes therefore in covering there should not be large slots and openings which are not closed by grid. But, the most important, polyfoam, having the closed structure of time, does not pass gases and water vapors at all. Therefore it categorically cannot be applied to warming of wooden fellings. Wood absorbs moisture from within rooms and if there is no opportunity to take away it through external walls, dampens. It leads to its defeat by fungi and insects and, eventually, to destruction. The frame houses built using timber frame constructions and panels on the basis of wood also should not be warmed by polyfoam. Expanded polystyrene is applied in warming of stone houses, but the builder has to understand that the humidity of walls indoors will increase. Respectively, the heatsaving effect will be slightly lower, than when warming by mineral wool and the internal microclimate will worsen. It is inevitable payment for low cost.
    Polyfoam is cut out precisely by the size of cells of framework, slots if necessary pressurize polyurethane foam. If plates well keep between framework elements, them it is possible not to fix to wall at all or to use small amount of “fungi” of 2-4 pieces/sq.m.
    Polyfoam is not blown, there is no need for wind-shelter film. If timber frame construction, for its airing it is necessary to leave the ventilated gap. At steel framework it is not obligatory.
  • The frothed polyethylene which is produced in soft rolls thickness in several millimeters is also quite often applied in the “dry” systems of warming. It can be addition to the main heater — to polyfoam. Frothed polyethylene can be located in any place of framework: at wall; or, on the contrary, under covering. Polyethylene paronepronitsay also should not be used in one design with mineral wool.
«Dry» technology of warming of facade

Framework for “easy” systems

Does not matter from what material to construct framework for “easy” systems. The main thing that it maintained the weight of covering and wind load.

  • Timber trellised frame construction is used more often for vinyl siding or wood casing. The best decision — the framework gathering in two-three levels from bars. The two first level are filled with heater, the third is intended for ventilation. The framework is collected from bars which two parties are planed and width in this direction is 5-6 cm that is close to heater thickness. Bars for the ventilated layer can be already — from 4 cm.
    Originally to house walls by means of the anchor dowels located with step of 20-30 cm bars in the vertical direction fix. When using mineral wool boards to minimize their draft, it is recommended to make cross crossbeams through 1-1.5 meters. At this stage it is very important to expose the equal plane precisely. Measurements are taken by means of plumb, level and cord, the space of bars from wall is regulated linings. Intervals between vertical elements of the first level of framework fill with heater, fixing it to walls “fungi”. The following stage mount the second level, having bars horizontally. Having finished filling with mineral wool, on the second level of framework adjust wind-shelter membrane by means of the stapler. If as heater polyfoam is used, in membrane there is no need. Over it vertically mount the third and last level. The space between bars of the third level is not filled, it serves for ventilation of walls, heater and elements of framework.
    The distance between bars of both the first, and second levels is recommended to be accepted multiply to heater width. For mineral wool this distance should be made on 5 mm already of width of sheets (50 or 60 cm). It will allow rationally, to cut out material without scraps. Useful will be to process previously wooden bars bioprotective structure.
    Timber frame construction can be not lattice, vertical, one – or two-level. The first level is constructed on all layer of heater at once, fixing bars on deviation from wall, enclosing under them lugs. The second level if it is — ventilating.
  • The steel framework can be used for any type of covering, including metal siding or metalprofile. More often it is carried out vertical, but maybe by lattice. Cost cheaper and it is simpler to work with standard galvanized profiles for plasterboard partitions 50, 75 and 100 mm wide. It is possible to use also elements of frameworks, they have smaller heat conductivity, big durability, but also stand more expensively. It is convenient to fix racks on deviation from wall by means of perforated suspension. They allow to regulate distance between wall and profile. Emptiness in profile also have to be filled with heater.

Many producers offer rather wide range of special metal and even plastic hinged frameworks for “easy” systems, but all of them cost expensive.

The trellised three-level scheme of framework is more preferable vertical. The number of bridges of cold decreases, heater draft decreases, the structure of the framework is stronger.

Framework for “heavy” systems

For “heavy” systems use only special, very strong and expensive complete steel frameworks. Elements of covering fasten on hooks, different holders.

Wind-shelter membrane and ventilation

By means of wind-shelter membrane we have already mentioned about need of protection of fibrous heater and timber frame construction. The membrane represents the nonwoven synthetic textile panel which is passing gases and water vapor, but interfering penetration of liquid and distribution of wind. The membrane has to be tense on all perimeter, without admissions.

The membrane cannot be confused with vapor at all insulating films which do not possess vapor transparency. Strangely enough, but “specialists” and some semiliterate sellers of the construction markets often quite so also do: confuse windscreen with vapor barrier. The last is cheaper, owners seldom argue. If “to pack” wooden house into vapor barrier film, the humidity of wood will reach critical level and it can decay for several years. Not the smaller loss will be caused also to timber frame construction. In the stone building of effect will be not so catastrophic, walls only will begin to dampen.

Many types of coverings and facings (siding, board, plates) in itself have thinnesses in joints of elements that provides partial ventilation. Nevertheless, in the lower and upper zones of covering it is necessary to place the additional slot-hole or other openings providing free air current from below up. Large openings in order to avoid penetration of rodents and insects, close mesh grids. Sheet materials (professional flooring) have a few joints and thinnesses, air exchange happens only at the expense of the lower and upper openings.

Covering for “easy” systems

The following types of materials for framework covering are most widespread:

  • Plastic siding. It cheap, has small weight and is simple in work. Except products, it will be required to gain necessary quantity of angle and connection sections. The choice of flowers is limited to light shades.
  • Metal siding. With several standard colors for extra charge it is possible to order set of shades on the RAL card.
  • Metalprofile. Is established vertically, as on fences. Costs cheaper siding.
  • Metal panels. Are made by the individual sizes in the form of the flat panel of trough-shaped section with curved edges. Can be made of steel of different thickness. Respectively, differ on weight and requirements to framework durability.
  • Wood casing. In the Scandinavian countries not rabbeted boards which have with an overlap one above another are extremely popular. Domestic builders prefer rabbeted finishing board which depending on the nature of profile and thickness is called lining, block house, imitation of bar. It is necessary to select and fix rabbeted boards for exterior finish so that the design and relative positioning of groove crest allowed wood to be narrowed and extend depending on humidity of outside air. Products from wood before mounting should not be overdried, it is necessary to sustain them at least two weeks in the conditions of natural humidity. Coloring and impregnation should be made before mounting. The covering from wood materials is recommended to be mounted on wooden framework. The mass of wood casing can be quite big.

Facing for “heavy” systems

In facing of “heavy” systems use plates from natural or artificial stone from 30х30 cm to 120 cm in size on one of the parties and even more.

Question price

Let’s set the estimated cost of materials for the most popular and inexpensive of the systems of “dry” outside warming, covering siding. The following materials will be necessary:

  • wooden bar of 4х6 cm — 6 items of m;
  • stone cotton wool, plates of 125 kg/m ², thickness of 5 cm — 2 m ² (0.2 m ³);
  • the siding is vinyl, standard color — 1.25 m ² (the raising coefficient on cutting and angular profile);
  • hardware (anchor dowel, “fungi”, screws);
  • wind-shelter membrane — 1 m ².
  • In such complete set the cost of complete set of materials approaches 30 for square meter. When warming by polyfoam the price will be lower.
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