EP0395777B1 - Apparatus to avoid going under the dew point near window flashings - Google Patents

Abstract

In known constructions and, in particular, in the renovation of old buildings, the problem arises that in the region of the flashings of windows and doors, the dew-point isotherm is not located in the window frame (7) but appears at the materials in the region of the interior, thereby resulting in a discontinuity in the curve of the dew-point isotherm. In order to avoid this disadvantage, the invention proposes that the curve of the dew-point isotherm of the room climate running through the heat-insulating zone (2) in the region of the static layer zone (1) or the monolithic wall passes without discontinuity or interruption into the window frame (7). <IMAGE>

Description

The invention relates to an arrangement according to the preamble of the main claim.

In the so-called layered construction of buildings, the building wall essentially consists of the static layer zone made of different materials, a heat insulation zone arranged in front of this layer, for example of mineral fibers, and a weather protection zone arranged at a distance from the heat insulation zone. With the environmental conditions, which must be assumed for the inside and outside according to the technical rules, the so-called dew point isotherm lies within the thermal insulation zone and runs parallel to the surface of the static layer zone. This course indicates that there is no thermal bridge and the level shows that the temperature does not drop below the dew point.

Problems with falling below the dew point occur with this known construction method and sometimes also with monolithic construction in the area of the connection from windows and doors, because due to the connection situation, the dew point isotherm is not led into the window frame, but emerges from the materials in the area of the indoor climate and this leads to a break in the course of the dew point isotherm. In addition, from the course of the dew point isotherms readable and additionally influenced by the choice of material, thermal bridges with a considerable additional heat loss arise. The associated moisture accumulation in the area of the transition between the frame and / or window frame and the static layer zone, which is additionally influenced by incorrectly placed steam brakes, leads to the destruction of the static layer zone and / or the window frame and (or at least) to a reduction in the thermal insulation of the building envelope.

These problems essentially arise from the fact that the actual thermal insulation cannot conclusively connect to the window frame, but ends in an uncontrolled manner, because the traditional trade separation has a negative effect in this connection area. The installation of the thermal insulation is always tendered separately, applied and carried out.

From "BBZ - DEUTSCHE BAUZEITSCHRIFT" 1988, September, No. 9, there are indications for window connections on the building structure for the new building, which result in the "Redline" - a diffusion-proof film that is glued to the shell of a building - see above should be guided that no interruptions should occur. Solutions on how this guidance can be achieved in practice in a simple manner are not given here.

From DE-A-22 27 817 a window for a wall provided with a ventilated curtain shell has become known, in which the gap between the wall and the curtain shell is to be covered by a metal or plastic cover. The task of this metal screen is to create a relatively simple component that is easy to assemble and is designed in a handsome manner. This known component does not have a positive influence on the dew point isotherm, in particular this component made of metal does not cause the dew point isotherm to shift into the window frame.

From EP-A-0 289 816 a surrounding frame for covering a wall opening for a door or the like has become known, the surrounding frame being provided with an end strip which is to be removed without difficulty in order to be reattached after a wall renovation, in order to be able to provide the wall with a new coat of paint or a new wallpaper up to the terminal strip. Influencing a dew point isotherm is not addressed at all in this known arrangement.

The invention is based on the object to provide constructive solutions to guide the dew point isotherms in the area of the window connection in the materialized area, without it exiting from the interior of the materials used in the overall connection area and leading to thermal bridges and heat losses.

This object underlying the invention will solved both by the teaching of the main claim and by the teaching of the independent claim 2.

In other words, the invention proposes to either shift the dew point isotherm appropriately by doubling the window frame, ie the window frame, from poorly heat-conducting material, or to achieve this influence on the dew point isotherm by using a main frame made of poorly heat-conducting material. This ensures in any case that there is no demolition in the area of the window connection, but the dew point isotherm is without significant

Shifting their surface-parallel course transferred from the building into the window frame, the window frame made of poorly heat-conducting material, so that even in the window frame there is only a slight shift in the dew point isotherm.

According to a further essential feature of the invention it is provided that the seal required between the static layer zone and the window, which simultaneously forms the vapor barrier, is arranged so that it lies on the warm side of the dew point isotherm.

Advantageous refinements of the basic teaching according to the invention are explained in the subclaims.

Embodiments of the arrangement according to the invention are explained in the drawings. The drawings show in the

1 to 5 different embodiments for the design according to the invention.

In the drawings, the static layer zone is generally designated 1, which can consist of different materials and thus forms the inner shell of the building wall. In front of it is a thermal insulation zone 2. In front of the thermal insulation zone 2 there is an air layer 3 of different dimensions. It is closed to the outside by the weather protection zone 4, which can also consist of different materials. 7 with a window frame is designated. Through this fundamental, in itself known structure, the required thermal insulation of a building is achieved and steam diffusion is ensured, since this is a diffusion-open design. In contrast to the monolithic structure, this type of construction is generally referred to as a layered construction.

In the embodiment according to FIG. 1, the transition from the static layer zone 1 or the thermal insulation zone 2 to the window is achieved by a main frame 5 which can be fixed to the static layer zone 1 by anchors 6. It is designed on its side facing the thermal insulation zone 2 in such a way that a secure and tight connection of the thermal insulation material is ensured. Since it is matched to the thickness of the thermal insulation material, it is ensured that the dew point isotherm running in the thermal insulation zone 2 can be absorbed by the main frame 5 and introduced into the window frame 7 without significant displacement.

The actual window frame 7 can be installed in different planes relative to the main frame 5, so that the dew point isotherm would be torn off in the transition from the main frame 5 to the window frame 7 in the case of a widely offset installation plane. In order to avoid this demolition, the window frame 7 according to FIG. 1 is provided with a doubling 8 made of poorly heat-conducting material, so that the demolition of the dew point isotherms is avoided and at the same time the tolerances customary in construction can be accommodated.

From Fig. 1 it can also be seen that the static layer zone 1 to the room side with a plaster layer 11 can be equipped, which in turn has a very low diffusion resistance. Therefore, a seal between the static layer zone 1 and the window frame 7, which at the same time forms the internal vapor barrier 10, must take place on the outside in front of this plaster layer. Furthermore, in the area of the doubling 8 and the window frame 7, when the window is installed in a lowered position (FIG. 1) to the static layer zone 1, thermal insulation 9 is provided, which is sealed off from the plaster layer via the vapor barrier 10. From the illustration in FIG. 1 it can be clearly seen that this vapor barrier 10 lies on the warm side of the dew point isotherm and that condensation precipitation in this area is therefore also ruled out via the moisture barrier.

In the embodiment according to FIG. 2, the window frame 7a is pulled far forward. In order to achieve a problem-free introduction of the dew point isotherms from the thermal insulation zone 2 through the main frame 5 into the window frame 7a and at the same time to ensure that the vapor barrier 10 lies on the warm side of the dew point isotherms and continues to be arranged between the static layer zone 1 and the doubling 8a can, the doubling 8a is broadened accordingly.

Since the main frame 5 is fundamentally installed in such a way that it follows the course of the shell (static layer zone), the tolerances permitted or customary in construction when installing the window frame 7a in the main frame must be compensated. The doubling is therefore also to ensure the correct structural and technical building physics tolerance compensation required. The possible different installation plane of the window frames 7a including the doubling 8 or 8a resulting from the tolerance compensation is indicated in FIGS. 1 and 2 by dashed lines. This applies in the same way to FIGS. 3 and 4 to be explained below.

FIG. 3 shows a configuration corresponding to the principle of the arrangement explained above, in particular an arrangement in which, as in FIG. 2, the window frame 7b is pulled forward far forward. In this embodiment, the main frame 5 is adjoined on its side facing the thermal insulation zone 2 by a plastic profile which, on the one hand, is particularly suitable for holding and receiving the thermal insulation material of the thermal insulation zone 2 and at the same time creates a moisture drainage 12 and - since it is plastic - from poor heat-conducting material. The main frame 5a is fixed via a dowel 6a with the interposition of a corresponding connector. Furthermore, the main frame 5 adjoins the static layer zone 1 in the area of the heat insulation zone 2 with the interposition of a compress belt 14, so that a heat-insulating air layer is created over a large part of the main frame 5 to the static layer zone 1.

The doubling 8b adjoins the area of the vapor barrier 10 via a connecting profile, so that the doubling 8a thereby consists of poorly heat-conducting material and of well-conducting material. The good heat-conducting material of the doubling 8b forms the one contact flank for the vapor retardant Sealing 10 to the static layer zone 1 and also ensures via the heat flow that this vapor barrier 10 is always on the warm side of the dew point isotherm. The poor heat-conducting material prevents an excessive temperature difference and at the same time forms the optical cover.

From the representation in FIG. 4, which corresponds essentially to the representation according to FIG. 3, it can be seen that the main frame 5 can also be fixed from the front in the static layer zone 1 if a recessed fastening screw 6b is used, whereby then for thermal insulation reasons the receiving hole in the main frame 5 is closed by a plastic plug 15.

In this arrangement too, a heat-insulating air layer 17 is provided between the main frame 5 and the actual static layer zone 1.

Now some information about the monolithic construction. The thermal insulation values required by law with the thermal insulation ordinance require "thick" walls in this construction. Wall thicknesses up to 50 cm are therefore "normal". Since no external thermal insulation is used in this construction - the so-called core insulation is not addressed here - the critical dew point isotherm is somewhere within the wall, the exact location being determined by the thermal insulation capacity of the bricks used inside the wall.

If the installation level of the windows is not matched to the position of the dew point isotherm within the wall, the isotherm will inevitably tear off and thus damage to moisture. Since the monolithic construction practically always has a stop for the windows, the installation level of the windows cannot be shifted arbitrarily (or specifically), but the window manufacturer is bound to the intended stop.

This situation is particularly critical when renovating windows in older buildings, which generally have "thick" walls. Here practically "leaky" single glazed windows are replaced by "tight" double glazed windows. In the old state there was therefore a large drop below the dew point because single-glazed windows acted as a "water trap" or better as a dehumidifier. The leaks then also caused a large (uncontrolled) air change.

After window renovation, the drop below the dew point is limited to small areas - practically to the thermal bridges. There is less condensation water loss and therefore a higher air humidity, which is increased by the low air exchange (tight windows).

A solution to the above-mentioned problems is shown in FIG. 5. Here, 1a denotes a monolithic wall, 7d a window frame, 10 a vapor barrier and 9 a thermal insulation.

The installation plane of the window is shifted so far inward via a main frame 5 that the dew point isotherm, which is shown in FIG. 5 at IT, cannot tear off and always runs in the material. The main frame 5 is therefore used here to shift the window into the correct installation level in terms of building physics.

Because the stop situation or the stop position cannot be changed (a so-called inner stop 17 can be seen in FIG. 5), which is typical of the monolithic construction, and by using the main frame 5 according to the invention, the dew point isotherm always runs in the material, i.e. where there is no warm, humid air it cannot get colder and where it does not get colder it cannot condense.

The existing situation in the new building area could only be changed if the window manufacturer had the chance to intervene in the planning, which is practically illusory. When renovating old buildings, the situation cannot be changed under any circumstances, but can only be changed by additional means, namely the aids described above.

Claims (7)

1. An arrangement for preventing deviation below dew point and/or thermal bridges in the area between shell and window or facing junctions where building walls are of laminar and monolithic construction, the course of the dew point isotherm of the atmospheric environment being conveyed without interruption from the building wall into the window frame (7, 7a, 7b, 7c), characterized in that the window frame (7, 7a, 7b, 7c) carries a lamination (8, 8a, 8b, 8c) of material of poor heat-conductivity, such as wood, plastics or the like, in its edge area situated in the area of the junction with the static lamina zone (1) and/or the heat insulation zone (2).
2. An arrangement for preventing deviation below dew point and/or thermal bridges in the area between shell and window or facing junctions where building walls are of laminar and monolithic construction, the course of the dew point isotherm of the atmospheric environment being conveyed without interruption from the building wall into the window frame (7, 7a, 7b, 7c), characterized in that the transition from the static lamina zone (1) and/or heat insulation zone (2) in the area of the opening for the window frame (7, 7a, 7b, 7c) to be inserted is formed of a main frame (5) of a material of poor heat-conductivity, such as wood, plastics or the like.
3. An arrangement according to one or both of claims 1 or 2, characterized in that a vapour barrier (10) known per se, which at the same time forms the wind seal, is a component of the arrangement and is arranged on the warmer side of the dew point isotherm, while a strip (9) open to diffusion is arranged on the colder side as a rain seal.
4. An arrangement according to claim 3, characterized in that the vapour barrier (10) is fitted between the static lamina zone (1) and the window frame (7) or between the static lamina zone (1) and the lamination (8).
5. An arrangement according to one or more of the preceding claims, characterized in that the interior finish (11) ends at the vapour barrier (10) (moisture barrier) also serving as a wind barrier and the free space as far as the main frame (5) is filled with heat insulating material (9).
6. An arrangement according to one or more of the preceding claims, characterized in that a plastics section (18) serving to support the heat insulating material in the heat insulation zone (2) is inserted between main frame (5) and heat insulation zone (2), which plastics section (18) simultaneously forms a moisture drainage means (12).
7. An arrangement according to one or more of the preceding claims, characterized in that a metal section of relatively good heat-conductivity is inserted between the lamination (8b and 8c) and the vapour barrier (10) for connection thereof.

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