To protect window structures and the exterior of the building, it is imperative to install window sills. Their second name is external window sill. They are made of a metal or plastic profile, which is installed under the window opening on the outside of the building. The main function of the elements is to protect butt joints from precipitation and condensation. The service life of the exterior trim and window frame also depends on this. In this article we will talk about the different tides, advantages and disadvantages of each material, as well as how to install an external window sill yourself.
Low tide is reliable protection from precipitation
What is a window tide, what is its purpose?
Window sills perform not only a decorative function. It simultaneously solves several problems:
- protection from moisture on the window sill and window frame;
- removal of moisture from glass;
- gives a finished look to the external design of the window opening.
If you neglect to install the low tide, moisture will accumulate on the window sill and the processes of destruction of finishing materials will begin: the plaster will fall off, the window frames will become unusable. If the slopes are covered with PVC, mold and mildew will form under them.
This is the main answer to the question of what slopes on windows are, and why they must be installed without fail. That is why the installation of structures is carried out not only for the decorative design of the opening, but also in order to prevent possible damage to the finishing and structures.
Low tide functions
The function of the element is to organize the unhindered flow of water that forms on the surface of glass and frames due to weather conditions . High-quality installation of this element affects the long-term operation of the plastic window as a whole. After all, when moisture gets on the frame or window sill, the building materials used in these areas begin to rapidly deteriorate. If the facade is plastered, the decorative layer begins to fall off.
A drainage system is installed to ensure water drainage from the glass and frame
A window opening with a tint looks neat and harmonious. Flashings for PVC windows are made from various materials and in different colors, so they can be matched to the window and façade in any design.
To fit into the overall design of the building's facade, the ebb should not look provocative and massive. Manufacturers of plastic windows and additional elements offer custom-made sills of the required length, width and color.
When building a new house, the installation of flashings should be carried out at the stage of facade work, when the seams and joints can be properly sealed. When installing a window in an already built house, the installation of sills must be done at the stage of installing a new window or glazing a balcony. When glazing a balcony, an upper ebb is also installed, which is attached to the upper balcony slab.
The upper ebb is installed when glazing the balcony
To ensure that the technology for installing a plastic window is not violated, you should worry about purchasing ebb and flow even at the stage of placing an order for the manufacture of a window system.
If measurements of a window opening for the installation of PVC windows are carried out by a representative of the manufacturer, then in the measurement sheet he will reflect the main dimensions of the recommended product, while the customer’s wishes regarding width and color will also be taken into account.
If there are several visually identical window openings on the facade, this does not exclude errors in their dimensional parameters relative to each other. Usually the height of such openings is the same, but the width may differ slightly.
The sill is made separately for each window according to pre-established measurements.
Therefore, for each specific window, a molding must be made according to individual measurements in order to reliably ensure the performance of its main functions related to the protection of the window structure and facade from moisture.
General requirements for geometric parameters of ebb tides
Before choosing an element, you should study the basic requirements and technical dimensions of the future product:
- The width of the external window sill depends on the width of the opening. To these dimensions you should add 3-4 cm per protrusion. It is also necessary to take into account the small angle of inclination of the tide. The minimum width of the product is 90 mm;
- to measure the length, measure the distance between the edges of the window opening from the outside. Add 3-4 cm on each side to the measurements obtained. The finished product should be 6-8 cm greater than the distance between the edges on the outside of the window opening;
- It is important to choose the correct configuration of the finished structure. The external window sill for a frame house will differ from the sill in a building built of brick or panel;
- The colors of the sills for windows and plinths should be combined with the external design of the window opening. For white windows, the external window sill should also be white. If the frames are made in a different color scheme, the window sill should be painted in a similar color or a tone darker.
Window sill configuration
Main selection criteria
And yet, it’s worth deciding what criteria you should pay attention to when choosing tides for plastic windows. Products perform important functions, so they must be of high quality and fit perfectly into the frame.
The main parameters for choosing ebb tides:
- Color. Manufacturers of castings made of steel, aluminum, and plastic offer a large selection of colors. On sale you can even find bright options that can complement unusual windows. The main thing is that the outer window sill matches the frame and fits into the overall style;
- Dimensions. When choosing, you need to consider the width and length. The length can still be adjusted, the profile can be trimmed. But the width of the ebb should be greater than the distance from the frame to the edge of the overhang of the rough window sill, so that it can fit freely on it. It is better not to use very wide products; their impact or weight load may be reduced. As a result, they may break off under the snow;
- The seller must have external plugs. Often in older homes there are various gaps that need to be sealed and this will require plugs.
The tides should be selected in accordance with the window frame; they should match their parameters. Experts advise installing aluminum profiles; they are the most practical and functional. This metal is lightweight, it can withstand loads, removes moisture well, and does not corrode. But you also shouldn’t forget about the decor; the outer window sill should emphasize the beauty of the window and complement its design in style and color.
General requirements for installation of ebb and flow sills
Improper installation of the external window sill will lead to rapid wear and tear. In addition, it will not perform its main functions; water will flow under it, which will lead to rapid deformation of window structures. When installing the drip sill, it is important to comply with the following requirements:
- Tight fit of all butt joints and their sealing.
- Treating butt joints with sealant is an additional, and not the main measure of protection against water ingress. The service life of the sealant is short, sooner or later water will get inside.
- Compliance with step-by-step technology for installing low tide on a plastic window.
- The width of the product should be 3-4 cm larger than the window slope.
- It is important to check the horizontal line using a level after installation. Rain flows should fall evenly on the window sill; if installed incorrectly, they will accumulate in one place.
- The base under the external window sill should be made of cement-sand mortar. It is not recommended to set the tide on several wedges and fill the voids with polyurethane foam, since sometimes when washing windows they sometimes get kicked. Polyurethane foam will not withstand such loads.
- The side edges of the slopes for plastic windows must be covered with finishing.
If you follow these simple rules, the low tide will last for quite a long time. It is much easier to adhere to the correct construction technology than to subsequently carry out repairs.
Correct installation of low tide
Plastic: good or bad?
Plastic window tints are considered the most “quiet”. When raindrops fall on them, there is almost no sound. And they are also considered inexpensive, which is important if the budget is limited. Only unpainted galvanization is cheaper, but its appearance, after several years of use, is not very attractive, the paint holds very poorly.
What are the disadvantages of plastic moldings? The fact is that plastic loses its elasticity under the influence of ultraviolet radiation, becomes brittle, and can crack under load. And, even if there are no serious cracks, there are always microcracks. They form over time and become filled with dust. After a couple of years, the once snow-white plastic becomes grayish or has a yellow tint. Nothing can wash it off. If installing window sills every five to ten years doesn’t bother you, you can use them too.
Plastic ebbs are two planes connected by jumpers. You have to step very carefully
The following disadvantages of plastic moldings are flammability and significant thermal expansion. Plastic melts at high temperatures. If a cigarette butt gets on it, a hole will be provided. It may not happen that often, but there is a possibility.
Thermal expansion manifests itself if the installation of window sills on windows is done rigidly - the strip is fixed with self-tapping screws. Then, in hot weather, it “goes in waves” and bends. Afterwards, it usually returns to normal. In order not to worry about thermal expansion, oblong rather than round holes should first be made in the edge of the ebb, to which it will be attached. When tightening the screws, do not press down the plastic too much. Then, when changing the size, the plastic casting will not “behave”.
Plastic drip installation
The second point is to leave a thermal gap on the sides, which is filled with silicone waterproof sealant (for outdoor use). In this case, thermal expansion will not cause a “wave”. The plastic will simply expand a little, compressing the sealant, then return to normal. So installing plastic drip sills has its own nuances.
What materials are window sills made from?
Not all materials can be used for external window sills. As a result, rust or smudges may form on the wall surfaces. It is important to figure out what is best to make them from. Let's take a closer look at the advantages and disadvantages of all recommended materials.
Sheet steel for external window sills
Non-galvanized sheet steel, despite the affordable cost of metal casting for plastic windows, is being used less and less for the production of structures due to its increased corrosion under the influence of precipitation. This is especially noticeable in urban environments, where the acidity of rain is much higher. To prevent these processes, it can be coated with special powder paint.
Over time, work will be needed to restore the coating with preliminary cleaning of rust. Another option is to coat the outer window sill with a polymer composition. This will not only extend the life of the product, but also reduce the noise produced by precipitation.
Despite the negative features, metal castings have a number of positive properties:
- high strength;
- Possibility of manufacturing to any customer size;
- various colors:
- resistance to temperature changes throughout the year. Tolerates both low and high temperatures;
- easy care;
- resistance to exposure to sunlight.
It is advisable to install metal flashings with additional sound insulation.
Important to remember! The product may become very hot in summer weather.
Fastening the metal ebb with self-tapping screws in 20 mm increments
Aluminum sills for windows
The strength of aluminum structures is much higher than metal ones. Thanks to this, their service life is longer. Products can be made up to 35 cm wide in brown or white. Also, coloring, if desired, can be done in any shade using powder paint. It is necessary to say about some negative aspects of aluminum:
- high price;
- increased noise during rain, which requires additional sound insulation.
Lightweight external window sill made of aluminum, painted brown
Plastic external window sills
Constructions made of polyvinyl chloride are considered the most practical. They have virtually no flaws. The advantages of the material include:
- moisture resistance;
- not affected by precipitation;
- simple installation;
- easy care;
- excellent sound insulation;
- beautiful appearance.
Polyvinyl chloride is not yet widespread enough. It has one significant drawback - fragility. Therefore, it is not recommended to install plastic window sills near schools or playgrounds. When the ball hits it, it will simply split. In addition, at low temperatures, strength also decreases significantly.
Installation of plastic structures is carried out on a slope with high-quality treatment of joints with sealant. In climatic regions with a predominance of low temperatures, it is still worth choosing a different material.
Plastic window sills require very careful care
Expert's point of view
Dmitry Kholodok
Technical director of repair and construction
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“It’s not worth talking about the durability of plastic castings. Sooner or later, sharp cracks will appear on them, into which moisture will get in, and moss may appear. The material will lose its original characteristics.”
Epoxy resin
Epoxy resin exterior window sills are considered super durable. It contains fiberglass. You should talk about the main advantages of the material:
- corrosion resistance;
- can be either independent ebbs or an overlay on an already installed window sill;
- reduced noise during precipitation.
External epoxy resin flashings can be produced in white, brown or black.
Polyester shimmers
An additional polyester layer is installed on the galvanized external window sill. In addition to decorative, it performs a protective function. The overlay can be made of the following materials:
- polyester;
- polyurethane;
- pastisol.
Among the main advantages are high strength and resistance to various acidic environments. They can be painted in different colors. Low tides require careful handling due to the possibility of scratches. The service life of such products can reach 30 years. Therefore, today polyester shimmers are rightfully considered the most practical.
Decorative polyester overlay for galvanized window sill
Galvanized window sills
Galvanized castings are the most common among analogues. Most often they are made in white and brown colors, they can also be laminated to resemble wood. The steel thickness is about 0.55 mm, the service life reaches several decades. If painting was done using powder paint, you need to be prepared for the fact that it may crack or fade over time.
It is important! The main nuance of galvanizing should be noted: noise during precipitation or gusty winds. The latter can occur due to improper installation.
For the production of galvanized castings, alloy steel is used, which gives the product additional strength and resistance to precipitation. Galvanized elements are often coated with a layer of polymer, which protects the product from the adverse effects of acidic environments. The price for sills for galvanized metal windows is affordable, which is an advantage when choosing.
Galvanized unpainted casting
2. Colors
By and large, your choice will be determined by exactly what material you chose to purchase the ebb from, as well as the availability of a color suitable for you. It is clear that when installing, say, a brown window block that imitates wood, it would be stupid to install a white tint. However, do not forget that the color palette of the tides is not the same and can vary greatly depending on the type. This, of course, is trivial, but if you want an exclusively red aluminum tint, you won’t get what you want. True, after listing the main features of each type, you will certainly be prepared for what awaits you on the market and decide on ideas in advance.
The main nuances of making and installing a metal ebb with your own hands
In order not to return to repairing the external window sill in a few years, you should take into account some advice from professional craftsmen:
- When marking a metal product, an allowance for slopes of at least 2 cm should be taken into account, while the edges should be folded upward. This will significantly extend its service life and also prevent the formation of condensation in winter;
- the protruding part beyond the window sill must be at least 4-6 cm, the angle of inclination must be at least 10°. This will allow water to flow freely from the external window sill;
- The width of the window sill should also be 2-3 cm larger, otherwise water will get inside the structure. You can pre-glue the slopes with vapor-permeable tape. It will remove excess moisture from wall surfaces. The tape needs to be placed on the slope with one edge, and on the cleaned window sill with the other;
- metal ebbs should be 4-7 cm into the side wall surfaces of the facade. This will not only securely secure the structure, but also protect against water leaks;
- if the slopes are finished with mortar, it is necessary to embed the external window sill into them at a distance of at least 1 cm. This will prevent the formation of leaks and preserve the exterior finish;
- It is important during installation to check the level of the tide using a level. This is necessary to prevent precipitation from accumulating in one place;
- Fastening to the window frame with rivets or self-tapping screws should be done from the middle. This will prevent its deformation and displacement. The distance between the rivets should be about 20-30 cm from each other;
- To seal butt joints, you should choose acrylic-based silicone sealant.
The installation of the drip tide is carried out at a slope with an insert into the façade. Vapor-permeable tape was used during installation
Step-by-step instructions for installing a metal sill on plastic windows with your own hands
Installation of the structure does not cause any difficulties. Before installing sills on plastic windows, you should familiarize yourself with the technological process and take into account the advice of professionals. Work should begin by cleaning the base. To do this, you need to remove excess polyurethane foam, cut off the protrusions and clean the surface of debris.
Expert's point of view
Dmitry Kholodok
Technical director of repair and construction
Ask a Question
“During installation of the drip sill, you need to check the perimeter of the frame. If poor-quality filling of voids with polyurethane foam is detected, the empty spaces must be additionally filled. After drying, cut off the excess and continue installing the external window sill.”
Next, the installation sequence is as follows.
| Photo | Description of work |
| First we make a slope from cement-sand mortar. After drying, we smooth out all the irregularities. | |
| We cut out a groove in the window structure using a diamond blade. The ebb will go inside the façade | |
| Taking measurements of the future low tide | |
| According to the given parameters, we cut out the external window sill on a machine or using special scissors | |
| We bend the workpiece on a bending machine | |
| We make markings on the back side of the product, then cut out the excess elements and bend the corners | |
| Apply “liquid nails” glue to the previously cleaned window sill. | |
| We install the ebb in the grooves of the facade | |
| All mating and butt joints should be treated with colorless sealant | |
| The external design of the window changes completely with the installation of low tide |
This process can be seen in the video:
Related article:
How to adjust plastic windows yourself? In a separate publication you can find detailed instructions on how to adjust windows in different situations.
Cost of ready-made window sills and their installation
Before purchasing an external window sill, it is important to decide on the final option. For PVC windows, plastic sills are suitable. For wooden windows, the ideal solution would be to install a galvanized or aluminum product. The cost of the finished version will depend on the material and size. The price range is quite wide.
We suggest that you familiarize yourself with the estimated cost of materials and give approximate prices for installing window sills on windows.
| Materials, type of work | Cost, rub. |
| Aluminum castings, linear m | 400-500 |
| Galvanized steel with color coating, linear m | 300-400 |
| Galvanized casting, linear m | 300 |
| PVC ebb, linear m | 200-300 |
| Installation of ebb tide, including preparatory work, linear m | 350-400 |
| Sealing gaps with foam | 250 |
| Sealing gaps with sealant | 250 |
| Cleaning gaps from polyurethane foam | 300 |
You can buy ready-made sills for windows with minimal dimensions at a price with installation starting from 2,000 rubles.
Copper sills are a very durable, but also the most expensive type of external window sill.
How to choose an external window sill for a window?
Before purchasing and installing the product, it is worth considering the fact that plastic ebbs are much inferior to metal ones in terms of strength.
It is better to give preference to a window tide that does not require special care. This is explained by the fact that during operation the product becomes very dirty, which means that rigorous cleaning may be required.
The external window sill must be light in weight, otherwise it will place a significant load on the facade. If you still want to install a heavy ebb, you will have to install a supporting structure first.
Before purchasing, you need to check the availability of special coverage. The best option is platizol, which gives the structure an attractive appearance and improves its strength.
Experts recommend choosing material manufactured by a well-known company. Famous companies value their reputation, so they offer only high-quality products.
