What Is The Reason for Water Leakage From Doors And Windows at Home?

1.Summary of Reasons for Water Leakage in Doors and Windows

Overall, there are three main reasons for water leakage in door and window products:

(1) The product itself has problems, such as gaps in the corners of door and window frames, mullions, etc., and no waterproof treatment has been done, or the product has not opened drainage holes and poor drainage, resulting in rainwater leakage from doors and windows on rainy days.

(2) Installation reasons include gaps in product sealing due to joint seams of door and window frames, inadequate hardware debugging, inadequate elasticity of rubber strips, inadequate sealing of door and window frames, gaps, leakage points, and water accumulation on exterior walls, or inadequate treatment of doors and windows and walls during installation, resulting in continuous water leakage problems during rainy and post rain weather.

(3) The first and second reasons for door and window leakage are caused by the product itself and later installation and debugging. What sets it apart is that there are no issues with the product or installation, but when extreme weather conditions (typhoons, strong winds and rain) occur, the air and water tightness of doors and windows exceed their maximum capacity, causing water to "pour" into the room.

2. Details of leakage caused by the product itself and solutions

Leakage problems caused by personal reasons are often due to structural defects in door and window products, or non-standard and lax production processes, such as the following common product leakage problems:

(1) Leakage at the corner splicing and mullion connection of door and window groups

This position is often caused by the lack of end face adhesive during product production, or low processing accuracy, resulting in unevenness and excessive gaps (visible light gaps).

Before connecting the corners and mullions of standardized door and window frames, it is necessary to apply end face adhesive first, and then assemble the door and window frames. The end face adhesive requires uniform and full coating, smooth connections, and tight seams.

The first solution to this problem is to purchase reliable products, such as asking the merchant "What are the production standards for doors and windows? How are the corners/mullions connected for doors and windows? Is there end face glue applied? Do the mullions have water stop clips? Are there any videos of factory production/corner assembly?" to learn more about the details of factory production of corner assembly and mullion connections.

Try to avoid purchasing door and window products that are not coated with corner glue (due to the lack of this process or non-standard production), and using movable corner codes for corner assembly (due to loose and loose corners).

For general needs, products with mechanical collision angle assembly and fixing of mullions with screws/corner codes can be selected. For high budget and high demand, products with adhesive corner code assembly or mullion technology can be chosen, which have higher strength and sealing performance.

Secondly, if the door and window products have been installed on the wall and water leakage is found, it is recommended to return or exchange the products if they have serious quality problems (such as loose corners, large gaps, etc.). If the problem is not serious, you can apply transparent sealant to seal the joint positions inside and outside the doors and windows.

2. Water ingress (leakage) at the glass pressure line or adhesive strip/bonding position

If there is water seepage at the position of the indoor glass pressure line on a rainy day, it is often due to the loose connection between the outer rubber strip (or glue) of the door and window glass and the glass, which poses a sealing hazard (air leakage point), and the rainwater cannot be smoothly discharged outward.

Normally, the two rubber strips inside and outside the glass are not completely sealed, but have a certain degree of elastic space, and their sealing performance is sufficient to resist rainwater infiltration in most cases. Even in strong wind and rain, if rainwater enters the glass groove, as long as the rainfall is not large, water can still flow outdoors through the drainage hole.

This requires good elasticity, full coverage, and no leakage points of the outer rubber strip (sealant) of the glass. There are drainage holes on the outdoor side of the glass slot, and the quantity, location, and drainage path are reasonable, unobstructed, and unobstructed.

The first solution to this problem is to purchase more reliable products, such as better quality rubber strips (choose materials, brands, and elasticity, please refer to previous articles for details), better handling of rubber strip corners (do not open or connect with glue), and guaranteed factory production standards (compare factory processing capabilities).

Secondly, if the door and window products have been installed on the wall and water leakage is found, the cause of the leakage needs to be identified first (visually inspect whether there are air leakage points at the position of the glass adhesive strip, check whether there are drainage holes at the position of the glass groove, pour water into the groove to see if the water can be discharged smoothly). If there is a sealing hazard, replace the adhesive strip or apply glue. If there are no drainage holes or the quantity is too small, make up for them. If the drainage is not smooth, clean up the debris or reopen the drainage holes.

3. Installation reasons, leakage details, and solutions

(1) Water leakage at the joint or exterior wall sealant (connection between door and window frames and walls)

If it rains, there will be dripping and leakage at the joint position of door and window frames (if any), the connection position between frames (splicing), and the connection position between door and window frames and walls.

Generally speaking, the outer wall glue around the door and window frames is often cracked and sealed due to aging after several years of use, leading to indoor water ingress and wall water seepage.

The splicing pipes used in various positions of the door and window frames (due to size and design requirements), as well as the connection positions between frames (including direct screw connections, splicing pipes, splicing strips, and splicing boards), are likely due to excessive splicing seams or lack of adhesive treatment (or gaps caused by loose adhesive).

The main solution to encountering water leakage in these locations is to visually inspect for gaps, glue, and complete sealant until the leakage point is identified, re glue, and observe for any further leakage in the future.

(2) The door and window sashes are not tightly closed, causing water seepage

Mainly for windows, some window sashes may not close tightly due to hardware not being properly adjusted, sinking, and other factors, resulting in sealing problems. Once the rain is heavy, rainwater can easily drip into the room along the gaps.

When encountering such problems, it is necessary to ask the installer to re adjust the window sash. The window sash can be locked tightly, but usually rainwater cannot enter.

At the same time, if the home is equipped with external windows or sliding windows, if conditions permit, remember to consider the installation position of the window frame. When the window is opened at around 30 degrees, it is best not to exceed the drip line above the eaves (if the eaves where the window is installed do not have drip lines, it can be installed within a few centimeters of the eaves).

This way, when the window is opened at a small angle on rainy days, raindrops will not splash into the room through the window sash

(3) Screw hole position

Screw connection between door and window frames and walls. Once the drainage of water on the outer side of the door and window frames is not smooth, over the years, the screws will be damaged (rusted, loose, etc.), causing rainwater to flow from the screw holes to the wall and damaging the indoor wall.

When encountering such problems, you can check the installation position of the screws one by one along the leakage location to see if the screws are loose or rusted. To prevent or repair leakage, screws can be replaced as appropriate, and sealant can be applied at the end of the screw to prevent rust and seal the screw hole.

In addition, to avoid such situations, a countersunk screw installation process can be adopted, and sealing glue with screw hole caps can effectively prevent such problems. Meanwhile, the installation position of screws should ideally be on the door and window frames near the indoor side, which can also serve as a preventive measure.

4. Leakage caused by gaps in the exterior walls

This mainly occurs in old residential areas, where the exterior walls are prone to aging, damage, and cracking. If the door and window frames are installed directly without any treatment, there is a high possibility of indoor water leakage in the later stage.

The correct approach should be to fill the gaps and leaks in the walls around the opening before installing doors and windows, as well as to carry out waterproofing treatment. If leakage is discovered only after installing the windows, it will cause damage to the interior wall decoration, and the subsequent process of finding and repairing the leakage points will be long and difficult.

5. External wall decoration surface causes water seepage

If there are decorative (functional) materials such as tiles, dry hanging stone, aluminum panels, insulation layers, etc. on the exterior walls, but they are not evaluated or treated during the installation of doors and windows, and are directly installed on the wall, there may also be indoor water seepage problems in the later stage.

The reason may be that the screw fixation damaged the integrity of these materials, and rainwater seeped into the room through gaps such as tiles. It is also possible that these materials themselves do not have complete sealing and waterproof performance, such as aluminum plates and insulation layers, which are likely to conduct water themselves, and doors and windows installed on materials cannot provide waterproofing.

Therefore, measures should be taken in advance before installing doors and windows on the wall. The common practice is to waterproof the materials or cut them to the installation position of the doors and windows, and then install the doors and windows after waterproofing.

6. Leakage caused by gaps in the lower window sill, water accumulation, and backflow

If rainwater leaks into the room from the lower window sill, there are two main reasons. One reason is that the window sill itself mentioned earlier has gaps (such as wall cracking), sealing hazards (such as tile gaps), and rainwater seeps through the indoor walls.

The second possibility is that the window sill may have poor drainage and accumulated water for a long time, which may increase the difficulty of waterproofing, damage the overall waterproofing of the wall, or cause accumulated water to "print" into the interior.

Therefore, in addition to paying attention to the four and five issues mentioned above, it is also important to avoid "high on the outside and low on the inside" when installing window sills. If possible, ceramic tiles, cement mortar, window sills, etc. can be used to create a slope and waterproof after the installation of the door and window frames.

7. Doors and windows with air and water tightness exceeding the maximum limit of water ingress, and solutions

Finally, in extreme weather conditions such as typhoons and strong winds and rains, the air and water tightness of doors and windows exceed their maximum capacity, leading to water "flooding" into the interior.

The most common type is sliding doors and windows that mainly rely on wool strips for sealing. The sealing performance is not high, and once the wind and rain are strong, rainwater can easily "enter" the indoor groove through the gaps of the sliding doors and windows. In addition, if the drainage is not timely (due to large water volume or high wind pressure), rainwater will overflow into the room.

Under extreme weather conditions, some window opening products may also be flooded. The main reason is that the rubber strip cannot withstand the test of strong wind pressure, and rainwater is forced into doors and windows by the wind pressure to enter the room. At the same time, the drainage holes are suppressed by the wind pressure, and rainwater (accumulated water) is also prone to run in the opposite direction towards the interior.