WO2010146221A1

WO2010146221A1 - Method for installation of fixed windows

Info

Publication number: WO2010146221A1
Application number: PCT/FI2010/000037
Authority: WO
Inventors: Viktor Tjurin
Original assignee: Viktor Tjurin
Priority date: 2009-06-04
Filing date: 2010-06-02
Publication date: 2010-12-23
Also published as: EP2440731A1; FI121282B; FI20090228A0; RU2011149702A

Abstract

Method for installation of fixed windows especially developed for buildings made of insulated reinforced concrete blocks or insulated masonry concrete blocks or insulated precast concrete elements, the exterior wall of the building having a thermal insulation core (C) between the inner leaf (A) and the outer leaf (B) of the wall. The frame of the window comprises a separate inner frame (1), which is attached mechanically by means of installation components and/or by gluing to the inner leaf (A) of the exterior wall and/or a separate outer frame (4), which is attached mechanically and/or by gluing to the outer leaf (B) of the exterior wall. The frameless insulating glass unit (D) is installed and glued between the inner frame (1) and the outer frame (4) or only to the inner frame (1) or only to the outer frame (4). The installation components and the materials used in the installation of the frames do not form a thermal bridge between the inner leaf (A) and the outer leaf (B) of the thermally insulated exterior wall.

Description

METHOD FOR INSTALLATION OF FIXED WINDOWS

FIELD OF THE INVENTION

The present invention relates to a method for installation of fixed windows specified in the patent claims.

BACKGROUND OF THE INVENTION

Heat transfer through a building envelope takes place via conduction and air leakage. As regards heat transfer through conduction, it is particularly important to eliminate local areas of high conductivity, i.e. thermal bridges. The building envelope should also be airtight. Air leakages have a negative effect on energy efficiency, moisture performance of building structures and indoor comfort.

Since, during cold seasons, the surface temperature of structures in the thermal bridge area is lower than the surface temperature of the surrounding structures, moisture-laden indoor air may condense on the cooler surfaces and cause harmful microbial growth and risk of decay. Lower surface temperatures resulting from poor air tightness or thermal bridges also have an effect on thermal comfort. Additional heating is used to offset draught discomfort, in which case the indoor air is warmer than would actually be necessary.

As low-energy construction becomes more widespread, the control of thermal bridges and air leakages will be underlined. The relative impact of thermal bridges on heat losses increases, as the thermal insulation capacity of building structures is improved. In contemporary low energy and passive buildings, the frames of both operable and fixed windows are typically the weakest link of the window assembly as regards heat losses.

Windows have an effect on the air tightness and thermal insulation properties of the building envelope and thus contribute to the energy efficiency of the entire building. The importance of fixed windows is growing along with requirements for improved energy performance of buildings. A fixed window is a more energy-efficient alternative than an operable window, particularly as structures age over time. Moreover, large windows cannot be operable for structural and safety reasons.

The thermal insulation capacity of windows like other building components is typically described by thermal transmittance, or so-called U-value. However, the U-values of the window frame and the window glazing alone do not give the full picture of the energy efficiency of the window. The entire window assembly, including the way it is attached to the adjoining structures, has an effect on energy efficiency.

According to building regulations, the joints between windows and the surrounding structures should be airtight. In practice, leakage of air does occur between the window frame and the building framework. In fixed windows, air leakage problems may also exist between the insulating glass unit and the window frame and possible mullions or transoms.

A review on state-of-the-art highly insulating window frames prepared by SINTEF, the

Norwegian research organisation, in 2007, indicates that two different main tracks are pursued to find better window frame solutions: The first option is to minimize heat losses through the frame itself by reducing its U-value as much as possible. The second option is to reduce the window frame area to a minimum and thus increase the net energy gain through the window. The net energy gain is calculated by subtracting the transmission losses through the windows from the solar energy entering the building through the windows. In climates where heating of buildings is required, the net energy gain is an important consideration. The energy gain through windows can be increased by maximizing the glazing area by using as slim frame profiles as possible. The authors suggest that ultimately, the best window frame might be no frame at all. Gustavsen A., Jelle B.P., Arasteh D. & Kohler C. State-of-the-Art Highly Insulating Window Frames - Research and Market Review. SINTEF Building and Infrastructure 2007.

hi buildings made of insulated reinforced concrete blocks or insulated masonry concrete blocks or insulated precast concrete elements, a fixed window with frames is typically attached to the building structure in the following manner: Blocks made of wood or pressure- treated wood are inserted in the insulation core of the concrete block or element. The wooden blocks are fastened in place with expanding polyurethane foam. The frame is screw fixed to the wood or pressure-treated wood blocks. The installation gap (the cavity between the window frame and the rough opening) is insulated with mineral wool, wood fibre wool or expanding polyurethane foam. Ln good installation practice, a breathable weatherseal, such as a self-expanding polyurethane sealing strip, is attached to the gap from the exterior, and the gap is rendered airtight from the interior by means of e.g. a sealing compound. Finally, the gap is usually covered with exterior and interior trims, hi practice, however, freehand filling of the entire gap with expanding polyurethane foam is a common installation method.

hi the wintertime, the dew point constantly moves inwards and outwards within the external wall of the building. If moisture is not allowed to escape from the installation gap to the outside, condensing moisture will stay in the wool insulation or the polyurethane foam used as insulation in the installation gap. In late winter/early spring, under worst case conditions, the wool insulation or polyurethane foam is wet and the perimeter of the window acts as an effective thermal bridge.

Moisture accumulating in the polyurethane foam also causes other problems. As the damp foam insulation is subjected to repeated freeze-thaw cycles over the years, the cell structure of the foam begins to rupture and the foam loses both its thermal insulation properties and its mechanical strength.

Within a few years from the installation, the wooden blocks inserted in the wall insulation and fastened in place with polyurethane foam may already be suffering from wet rot because of exposure to moisture. Mould damage will follow and when the wooden blocks reach a sufficient degree of decay, the fastening of the windows will rest entirely on the structurally deteriorated polyurethane foam and fixing screws.

If the window frames are fastened with electro-galvanized screws, the service life of such screws will be shortened under the above conditions, especially if pressure- treated wood blocks are used in the window installation, hi the presence of moisture, the galvanic corrosion triggered by the wood treatment substances in the pressure-treated wood will cause the steel screws to disintegrate. In a conventional fixed window, the insulating glass unit is attached to the frame by the window manufacturer. It is also possible to install a fixed window by mounting a frameless insulating glass unit into a frame structure attached to the building framework. As regards air leakages and thermal bridges, such an installation on the building site is not necessarily any more advantageous than the conventional installation method for fixed windows.

OBJECT AND ADVANTAGES OF THE INVENTION

The present invention aims to correct the aforementioned deficiencies and problems. The object is achieved by a fixed window installation which is airtight even as structures age. in which the installation method and the materials used do not constitute a thermal bridge between the inner and outer leaves of the exterior wall. the U-value of which is lower than the U- value of conventional installations of fixed windows with frames. in which moisture or mould problems do not occur. in which the window is more securely attached to the exterior wall and which has a longer mechanical service life than conventional installations of fixed windows with frames. - which enhances thermal comfort by reducing the sensation of cold draught. which improves the net energy gain through the windows.

SUMMARY OF THE INVENTION

For the description of the invention, the exterior wall of a building is divided in three sections: outer leaf, thermal insulation core and inner leaf.

The present invention concerns an installation method, in which a separate inner frame is attached to the inner leaf of the exterior wall and/or a separate outer frame is attached to the outer leaf of the exterior wall. The insulating glass unit is mounted and fastened between the inner and outer frames or only to the inner frame or only to the outer frame. The installation method according to the present invention is particularly well suited for low- energy and passive buildings since the resulting overall energy efficiency is better than the energy efficiency achieved in the conventional installation method for fixed windows. The advantage becomes more pronounced as the structures age over time.

Advantageously, the installation materials and installation components used in the installation method do not form a thermal bridge between the outer and inner leaves of the exterior wall. Moreover, the insulating glass unit fastened to the securely attached separate frames enhances the structural rigidity of the exterior wall.

The installation method further advantageously makes it possible to reduce the sensation of cold draught by allowing warm indoor air to circulate within the inner frames. If necessary, additional heating can be provided by incorporating electric heating wires in the inner frames. Energy can thus be saved in circumstances in which heating would otherwise be switched on because of a sensation of draught from the window jambs even though the outdoor temperature would not yet necessitate heating. By heating the electric wires inserted in the inner frames, it is possible to eliminate the cold draught sensation in living spaces and decrease the length of the actual heating season. Further, advantageously, the installation method contributes to energy efficiency when interior spaces are air conditioned in the summer.

The installation method provides fresh architectural opportunities since, looking from the inside, no frames are visible in the finished window opening. It is also possible to finish the window opening from the exterior leaving the frames only partly visible or not visible at all. The installation method also improves the net energy gain through the windows.

Both the inner and outer frames may incorporate the necessary trims, either as integral parts of the frames or to be attached, for example, by means of a quick release locking mechanism, in which case the installed frames also finish the window opening from the interior and/or from the exterior. The insulating glass units can be dimensioned and ordered after the installation of the inner or outer frames, thereby reducing the potential for errors in the insulating glass unit order. If necessary, the insulating glass units may also be ordered first, in which case the frames are dimensioned and installed to correspond to the size of the insulating glass units. Because of the frames which are pre-attached to the building structure, the installation method described in the present invention facilitates quick, accurate and reliable crane-assisted installation of the insulating glass units.

The installation method with adjustable installation components, described in detail in the following, relates to buildings made of insulated reinforced concrete blocks or insulated masonry concrete blocks. In such buildings, the rough window openings are typically not perfectly square, level and plumb. If the rough openings are sufficiently square, level and plumb, as in insulated precast concrete elements, for example, it is possible to use less intricate prefabricated or factory-made installation components. This speeds up the installation process by decreasing the number of installation steps. The separate inner and/or outer frames and the insulating glass unit may also be fixed in place in the precast concrete element at the factory.

BRIEF DESCRIPTION OF THE DRAWINGS

One exemplary embodiment of the present invention shall now be described in detail with reference to the attached drawing, Fig. 1.

DETAILED DESCRIPTION OF THE INVENTION

Before the installation begins, the rough opening is measured and checked to make sure that it is square and the sides of the opening are level and plumb. If necessary, adjustments are made to provide a square, level and plumb opening.

In this exemplary embodiment, the installation of the window is carried out by first attaching the inner frame to the inner leaf of the exterior wall of the building, which is followed by the installation of the insulating glass unit to the inner frame, after which the outer frame is attached to the outer leaf of the exterior wall. Finally, the insulating glass unit is secured to the inner and outer frames by means of a sealant. It is also possible to follow a reverse installation order by first attaching the outer frame to the outer leaf of the exterior wall of the building, which is followed by the installation of the insulating glass unit to the outer frame and then the installation of the inner frame to the inner leaf of the exterior wall. Finally, the insulating glass unit is secured to the inner and outer frames by means of a sealant.

In this exemplary embodiment, each vertical and horizontal member of the inner and outer frames is attached separately. The frame members may also be installed in directions deviating from the vertical or horizontal planes when the insulating glass unit is not rectangular in shape. This exemplary embodiment involves the installation of a rectangular fixed window.

The inner frame is a profile with square, rectangular or some other cross-sectional shape. The profile may be either hollow or solid. The inner frame may be made from anodized aluminium, stainless/acid-proof steel, composite, plastic or some other appropriate material. To ensure the adhesion of the glazing sealant, surface preparation of the inner frames may be necessary.

The inner frame (1) is attached to the inner leaf (A) of the exterior wall using installation components. The installation components comprise a predrilled anchoring profile (2), which is attached mechanically and, if necessary, also glued to the inner leaf (A), adjustment rods (3) with internal or external threads and adjustment/locking accessories (8 and 9). There are two or more adjustment rods (3) for each inner frame member. The inner frame (1) is attached to the anchoring profile (2) by means of the adjustment rods (3) and the adjustment/locking accessories (8 and 9). The necessary adjustments to the vertical and horizontal members of the inner frame are made using the adjustment rods (3) and the adjustment/locking accessories (8 and 9). If necessary, tensioning screws and temporary shims are used for the adjustment.

Once measurements have been taken to verify that the inner frame (1) is in a single plane on which the insulating glass unit (D) can be attached, the inner frame (1) assembly is secured with dots of adhesive to the thermal insulation core (C) of the exterior wall. Once the adhesive has cured, the entire gap between the inner frame (1) and the thermal insulation core (C) of the exterior wall is finished by means of an appropriate elastic/flexible sealant (10), which provides an airtight seal to the ventilation space (15) at the perimeter of the insulating glass unit (D). The dimensions of the inner frame are confirmed to specify the exact size of the insulating glass unit to be ordered.

All members of the inner frame are installed following the same installation procedure. In the installation of the bottom horizontal member of the inner frame, allowance is made for support blocks, on which the insulating glass unit rests. The support blocks transmit the load of the window pane to the building framework. These support blocks are mounted and secured mechanically to sustain the weight of the insulating glass unit. The blocks are mounted at a convenient point in view of the installation sequence of the inner frame. The bottom horizontal member of the inner frame may also be attached after the insulating glass unit has been fixed in place.

The outer frame (4) is pre-fitted before the installation of the insulating glass unit (D).

Prior to the installation of the insulating glass unit (D), care is taken to ensure that the exterior wall thermal insulation core (C) facing the edges of the insulating glass unit (D) forms a uniform surface. Possible cracks or cavities in the insulation core (C) are filled with an appropriate material, which is substantially impermeable to water vapour. The insulating glass unit (D) is fixed to the inner frame structure (1) using an appropriate self- adhesive sealing/glazing tape (11).

Once the insulating glass unit (D) has been fixed to the inner frame (1), a self-adhesive sealing/glazing tape (12) is applied to the outer surface of the insulating glass unit (D), where the outer frame (4) will be attached. The outer frame (4) is fitted in place and attached mechanically and/or with an appropriate sealant to the outer leaf (B) of the exterior wall. The ventilation space (15) at the perimeter of the insulating glass unit (D) is rendered airtight toward the exterior either by an airtight fixing of the outer frame (4) and/or by applying a sealant (14) which also acts as a thermal break. If the installation is done in reverse order, i.e. the outer frame (4) is installed before the inner frame (1) or if otherwise necessary, the outer frame (4) is adjusted to the required position by means of appropriate installation accessories.

Finally, the insulating glass unit (D) is secured to the inner frames (1) and to the outer frames (4) with a sealant (13) specified by the structural or glazing engineer for this particular application.

Once the sealant (13) has cured, pressure equalizing holes are drilled from the exterior through the outer frame (4) profile and the sealant (14) to the lower corners of the vertical members of the outer frame (4). Possible condensation accumulating in the ventilation space (15) at the perimeter of the insulating glass unit (D) will also be able to escape through the pressure equalizing holes. The installation of the outer frame (4) is finished by attaching weather resistant exterior trims (5) which cover the outer frame (4). Thermal insulation may be added to the space between the exterior trim (5) and the outer frame (4).

On the inside, the space between the inner frame (1) and the anchoring profile (2) is filled with extra insulation (6) with insulation properties matching those of the thermal insulation core (C) of the exterior wall. A glazing bead (7) is attached onto the inner frame (1) against the insulating glass unit (D). The window recess is subsequently coated with plaster, lined with gypsum/plaster board or wood or finished in another way. Necessary attachments and equipment, such as shades or blinds with side guides, lighting fixtures, controls etc. may be embedded and fixed in place before the finishing of the window recess.

If the inner frame is made of a hollow profile, holes can be made in the upper and lower corners of the vertical members of the inner frame to allow warm indoor air to circulate through the holes within the inner frame. Electric heating wires may also be inserted in the hollow inner frames.

Guidelines and instructions provided by the structural engineer regarding the materials employed, material thicknesses etc. are observed in the installation of the frame structures. Fastening, bonding, gluing, sealing, adjusting and other installation steps are carried out using methods that are obvious to a person having ordinary skill in the art, and these steps are not described in more detail here.

The foregoing description is for the illustration of the principles of the present invention rather than limitation of the present invention to the foregoing particular embodiment. Numerous variations and modifications of the installation method are possible, falling within the spirit and scope of the present invention as described in the following claims.

Claims

1. Method for installation of fixed windows, especially developed for buildings made of insulated reinforced concrete blocks or insulated masonry concrete blocks or insulated precast concrete elements, the exterior wall of the building having a thermal insulation core (C) between the inner leaf (A) and the outer leaf (B) of the wall, characterised in that

- the frame of the window comprises a separate inner frame (1) and/or a separate outer frame (4) both of which support the insulating glass unit (D), - the inner frame (1) is attached mechanically with installation components (2, 3, 8, 9) and/or by gluing to the inner leaf (A) of the exterior wall,

- the outer frame (4) is attached mechanically and/or by gluing to the outer leaf (B) of the exterior wall,

- the ventilation space (15) at the perimeter of the insulating glass unit (D) is finished airtight toward the interior by means of a sealant (10) to produce a vapour barrier and airtight toward the exterior either by the airtight fixing of the outer frame (4) and/or by means of a sealant (14),

- the frameless insulating glass unit (D) is installed and glued in an airtight manner between the inner frame (1) and the outer frame (4), and - the installation components and the materials used in the installation do not form a thermal bridge between the inner leaf (A) and the outer leaf (B) of the thermally insulated exterior wall.

2. The method for installation of fixed windows according to claim 1, characterised in that the window is installed in such a manner that the window frame only comprises the inner frame (1) which supports the insulating glass unit (D), and the frameless insulating glass unit (D) is installed and glued to the inner frame (1).

3. The method for installation of fixed windows according to claim 1 , characterised in that the window is installed in such a manner that the window frame only comprises the outer frame (4) which supports the insulating glass unit (D), and the frameless insulating glass unit (D) is installed and glued to the outer frame (4).

4. The method for installation of fixed windows according to claim 1 or 2, characterised in that the inner frame (1) is adjusted to the required position by means of the installation components (3, 8, 9) of the inner frame (1).

5. The method for installation of fixed windows according to claim 1 or 3, characterised in that the outer frame (4) is adjusted to the required position by means of the installation accessories of the outer frame (4).

6. The method for installation of fixed windows according to claim 1, characterised in that the choice of the installation sequence and the installation direction of the insulating glass unit (D) is either such that the inner frame (1) is installed first, followed by the insulating glass unit (D) and finally the outer frame (4), in which case the insulating glass unit (D) is installed to the inner frame (1) from the exterior, or such that the outer frame (4) is installed first, followed by the insulating glass unit (D) and finally the inner frame (1), in which case the insulating glass unit (D) is installed to the outer frame (4) from the interior.

7. The method for installation of fixed windows according to claim 2, characterised in that the inner frame (1) is installed first, and the insulating glass unit (D) is installed to the inner frame (1) from the exterior.

8. The method for installation of fixed windows according to claim 3, characterised in that the outer frame (4) is installed first, and the insulating glass unit (D) is installed to the outer frame (4) from the interior.

9. The method for installation of fixed windows according to claim 1 or 3, characterised in that pressure equalizing holes are drilled at the lower corners of the vertical members of the outer frame (4).

10. The method for installation of fixed windows according to claim 1 or 2, characterised in that holes opening to the interior are made in the lower and upper corners of the vertical members of the hollow inner frames (1), through which holes warm indoor air circulates within the inner frame (1).

11. The method for installation of fixed windows according to claim 1 or 2, characterised in that electric heating wires are inserted in the hollow inner frames (1).

12. The method for installation of fixed windows according to any one of claims 1 - 11, characterised in that the inner frames (1) and the outer frames (4) are made of standard profiles, prefabricated standard profiles or factory-made special profiles.

13. The method for installation of fixed windows according to any one of claims 1 - 11, characterised in that the necessary trims are incorporated in the inner frame (1) and/or outer frame (4) structures, in which case the installed frames simultaneously finish the window opening from the interior and/or from the exterior.

14. The method for installation of fixed windows according to any one of claims 1 - 11, characterised in that the inner frames (1) or the outer frames (4) are installed or pre- fitted at the most advantageous point in time in view of the construction schedule, even much before the delivery and installation of the insulating glass units (D).

15. The method for installation of fixed windows according to any one of claims 1 - 11, characterised in that fixed windows are installed in insulated precast concrete elements in factory conditions using the said installation method.