Correct installation of the roof window

Proper installation of a roof window is a key factor in its subsequent and proper operation. The installation of the roof window is usually done by professionals. The assembly process itself is easy and quick, which is why DIYers may be tempted to do such work themselves.

The packaging contains detailed installation instructions allowing non-specialists to properly install a roof window in the roof structure. The sealing connection between the window and the roofing is ensured by a sealing collar, which should be selected according to the type of roofing. FAKRO also offers a special XDP insulation kit that allows you to make the correct thermal insulation around the window. Below we present the roof window installation – in the version on battens. More informations

Typical errors that are made during the installation of windows not only lead to problems with the windows themselves, but also, e.g., deteriorate the thermal insulation of the walls. We suggest what to look for when installing windows.

During installation of window joinery, typical mistakes are often made. They usually lead to deformation of the windows and damage to their connection to the wall. The effect of this is the penetration of water and cold air into the interior of the room and a significant reduction in the thermal insulation of the building partition. Progressive changes mean that the window is less and less effective and becomes a source of growing problems for the homeowner.

An unacceptable mistake made during the installation of windows is to leave the old sealing material (when replacing) windows or debris and dust (also when installing new windows). Left corroded building materials, defects in masonry and misaligned surfaces prevent proper sealing of the space between the window and the wall and the correct installation of the window sill.

Undesirable phenomena: dirt left behind absorbs moisture. Foam on uncleaned ground is not bonded to the wall – gaps are created through which moisture passes and air is blown. The so-called thermal bridges (places with worse heat transfer coefficient, through which we lose heat from inside the house). The connections are unsealing.
The effects of the error: increasing dampness of the wall, leaking water from under the window sill, drafts caused by the blow of air at the window frame. Conditions are created favoring the development of mold fungi.

Too few anchors or dowels used to install the window
The use of too few anchors / dowels or too large spacing reduces the stability of the structure.

Undesirable phenomena: a single attachment is overloaded, which causes lateral movement of the window. As a result, the window frame deforms.
The effects of error: window deformation, unsealing of joints, penetration of moisture into the interior, drafts and air blows felt in the room.

Embedding windows without using blocks or wedges
The window frame must be leveled (vertically and horizontally) and after comparing its diagonals, stabilize it with wedges. Thanks to this, we can be sure that the frame actually has right angles.

Undesirable phenomena: windows are unstable, they begin to move vertically (the frame deforms). The window is not level or properly sealed.
The effects of the error: window deformation, plaster cracking, moisture penetration between the window and the wall, drafts.
Installation of the window without a window sill
A window sill strip is a way to seal the window and window sill connection well. It is screwed to the frame and is to facilitate the installation of external and internal window sills, which must be placed under the window frame. It’s best to use a warm window sill.

Unwanted phenomena: it is impossible to install an internal window sill under the window frame, rain water penetrates the frame and then into the room. The connections are unsealed.
The effects of the error: dampness of the wall under the window, freezing of the wall, leakage of rainwater into the building, drafts, gradual corrosion of dowels and anchors.

Setting the window in the threshold with incomplete sealing, on unevenly arranged blocks
Undesirable phenomena: the window is unevenly set, stresses and lateral movement of the window appear (the result is its deformation). There is a gradual leakage of water through the unsealing contact between the window and the wall – buy Optilook windows online
The effects of the error: window deformation, gradual rainwater seepage into the interior, drafts, wall dampness, moisture rising on the windowsill.

Alignment of the window with the jamb – no expansion gap, no window sealing at the junction of the window frame and the jamb

Phenomena: this installation means that the window contact with the trench cannot be sealed. Rain water and cold air easily penetrate the resulting gap. An uninsulated contact not only constitutes a leak, but also becomes a thermal bridge.
Consequences: dampness of the wall, formation of streaks (excellent substrate for the development of mold fungi), in winter: wiping of moisture on jambs near window frames.
The window frame is completely hidden behind the Hungarian

Most often, this error occurs with too wide jambs.

Phenomena: rainwater leaks under the leaf frames, while a wet notch forms a thermal bridge.
Consequences: with intense rainfall, water leakage into the room, sealing gaskets, worse thermal insulation of the window.
Aligning the window flush with the window frame – no expansion gap. Sealing only from the side of the Hungarian
Most often, this error is the result of improperly measuring the window opening. When the window is too wide in relation to the window opening, I have no way to do expansion slack and fit insulation.

Phenomena: it is impossible to seal the window contact with the window frame. A gap is created through which moist air penetrates inside, water condensation occurs. There is no stress compensation.
The effects: moisture in the jamb, moisture penetration, warping and sticking of windows when the temperature rises. Especially in summer, the windows warp and stick.
Excessive expansion joint from the jamb side
Most often this assembly error occurs with too wide jambs.

Phenomena: the window is not sufficiently fixed in the reveal (the dowel is subjected to strong bending), so the window moves with wind pressure. The contact leaks, after some time rain water begins to seep into the frame and jig. Consequences: moisture wicking, airflow into the room, water leakage into the room after some time.

No sealing from the jamb side and the jamb

Phenomena: the window is not protected against moisture and air – rainwater and cold air easily penetrate the room. Penetrating moisture easily condenses.
Effects: dampness of walls and plasters, drafts and leaks, formation of conditions for mold growth, moisture condensation.
The connection between the wall and the window frame was made of plaster mortar. As a result of the thermal expansion of the profile and the action of freezing and thawing water, such a connection is gradually degraded and loses tightness.

The connection between the window frame is made exclusively with the use of polyurethane foam. Foam exposed to atmospheric conditions. The connection in this way is unacceptable, not only because of the obvious aesthetic effect. Foam exposed to UV radiation degrades, destroys and crumbles, exposing the connection to water. The long-term effect of such a seal is the destruction of all layers of the connection, dampness of the wall and significant losses of energy for heating.