Why not order a new plastic window in one piece? Why are these vertical and horizontal crossbars constructed on it? Window masters will easily give an answer to this question. As they will tell you what an impost is. This will be the main topic of the material. We will find out what is hidden under this term, why an impost is needed, what varieties it comes in, how it differs from a shtulp, why it is necessary in the structure and how it is attached.
What is this?
As for plastic windows, today these are far from standard designs. They are divided according to many features. However, the main terms still remain general. Impost is one such concept that applies to all window systems.
To make the right choice and not regret the installed window, it is still worth being aware of the specific terms used by window workshop employees. And what we are analyzing here is among the most important.
Impost is an internal plastic profile. In other words, this is what amplification is called,which can be mounted vertically or horizontally inside the profile. In simple terms, an impost is a support, a kind of bridge for window sashes. Now on to the next topic.
Purpose of the element
What is impost needed for? What is it in plastic windows? This is a profile with which several sashes of window structures are connected, while remaining independent from each other at the time of opening. Such an element was created to facilitate the operation of the structure.
This can be appreciated, for example, while washing windows. Also, such drop-down sashes are often equipped with rooms where frequent and complete ventilation is important.
Profile location
Impost - what is it in plastic windows? The essence of this concept reveals both the definition and the photographs of the element given in the article. Now let's move on to the technical part - the location of the element.
The impost is located in the structure, based on the number of wings to be installed. If this is a standard plastic window, then the mullion profile will vertically divide it into two halves.
Profile fastening
At the same time, each profile system will be distinguished by its own technology for attaching these elements:
- Steel mullions of the frame stand out for their high strength. They are welded into the profile from above or below. Then they are additionally reinforced with PVC walls.
- Connecting the impost with the profile with end screws. It is also used herehigh strength steel element. The screws will be screwed into the part that is equipped with the reinforcement chamber of this system component. It is important here the correct location of the attachment points of the window block on the impost area.
Before joining it with the frame, the latter, having an L-shape, must be milled. For fastening use a standard type of screw (5x40, 4x40). The choice of one or another mounting option depends on the type of window system.
Welding or fixation?
Which of the above methods to choose? Is the impost welded into the window frame from above and below, or is it mechanically fastened with screws? Both methods have both advantages and disadvantages.
It must be remembered that the main component of the entire window frame, a plastic window, which directly affects the rigidity of the structure as a whole, is a reinforcing steel element. It sits inside a plastic frame. PVC walls, on the other hand, have stiffness several orders of magnitude lower.
From here it becomes clear that the welding of the impost will not give a more rigid fixation. The fact is that in this case it is fixed only with PVC walls, the average thickness of which is within 3 mm.
And what about mechanical fastening? In this case, the master will use already steel bolts, the average diameter of which is 6 mm. This element will already be directly unscrewed into a solid embedded part. What is important, it is located in the reinforcement chamber of the impost itself.
We see now that the choice of mountwill not affect the strength of the entire window structure.
Pros and cons of impost
In fact, the element we are considering is nothing more than a horizontal or vertical crossbar. The window impost divides the latter into two or more parts, into each of which one of the elements will be inserted: a window sash or a double-glazed window (non-opening blind sash).
What are the benefits of using this design? Window wizards highlight the following:
- Possibility to install multiple sashes.
- Window sashes in this case can be of two types - both rotary and tilt-and-turn, at the request of the customer.
- The ability to open the sashes in any sequence - impost makes them independent of each other.
- Several options for fixing the mosquito net. It can be installed on one or both doors.
At the same time, the impost mount has only one drawback - there is no possibility of a panoramic view from the window. The picture is spoiled by a vertical or horizontal bar.
Pros and cons of shtulp
Looking at the photo of the impost, you probably noticed that such an element will always "cut" the view from the window along or across. If a beautiful panorama is important to you, then you can refer to ordering an alternative to this element.
Shtulp is such a substitute. This is the name of the profile that will be attached to one of the wings from the outside. It has two purposes - sealing and holding the flaps closed.position.
An undoubted advantage of the shtulpa - when the doors are opened, you will enjoy a panoramic view without crossbars. However, such pleasure has a number of undoubted disadvantages for the customer:
- Sashes can only be opened one at a time. Thus, first the one without the shtulp is dissolved, and then the sash with the shtulp. The left shtulp will be attached to the left sash, the right one, respectively, to the right.
- The sash with the installed sash can only be turned. It will no longer be possible to throw it back.
- In this case, the mosquito net is installed not on one leaf, but on the entire panoramic opening. In some cases, this leads to a number of additional costs, as it becomes necessary to use a wider profile for its manufacture.
Features of window division by element
Window impost is a horizontal or vertical bar that will divide your window into two or more parts. In each of them, the master will insert a blank double-glazed window or a window sash according to your wishes.
There is no specific place for installing the impost. Therefore, you can make one sash already another as much as you want. Make a wide deaf double-glazed window and a narrow sash for ventilation. Or, on the contrary, design the parts of the window to be equal, so that it is convenient to wash the glass from the outside of the structure.
Such variations help save money. Installing blind double-glazed windows and narrow sashes is much cheaper than installingtwo equal or one wide. It also helps to improve the lighting of the room. Wide blank glass lets in more light.
Element Varieties
The impost of the window frame can be of several varieties. One or the other is chosen depending on the purpose of installing this element. There are four types in total:
- Horizontal.
- Vertical.
- Decorative.
- For balcony frames.
Let's take a closer look at each variety.
Vertical elements
The most common imposts of plastic windows. They are used everywhere for all designs, implying the number of valves more than one. Here the impost is one of the main elements. The fact is that all the fittings, as well as the window sash in the structure, will be attached to it.
Standardly, there is only one impost - it divides the window into a part with a sash and a part with a blank double-glazed window. But non-standard solutions are also not uncommon: three-leaf windows with two imposts, four-leaf windows with three, and so on. False profiles are also possible. That is, there are no profiles at all in such cases, and the doors open into each other.
Horizontal elements
A special kind of element that divides the structure horizontally rather than vertically. Usually one such impost is used, delimiting the window into two parts. For example, on the lower deaf wide double-glazed window and the upper small window.
Why are horizontal mullions mainly installed?In order to attach accessories to an element. Much less often - within the framework of decorative purposes. Another practical application is to break apart too heavy a double-glazed window.
When the height of the structure exceeds 170 cm, it is already heavy. In such cases, you can not do without the installation of a horizontal impost. Here it will hold the fittings, and not the frame, as in standard designs.
For Russian brick houses from the Stalin era, it is standard to install plastic windows with horizontal imposts, since the window openings in such buildings are quite high. The upper parts are usually left blank, and an opening sash is installed in the lower parts.
Balcony doors
For such structures, the installation of mullions is strictly required. Some customers think that the impost here performs only an aesthetic function. Yes, it beautifully decorates the door, separating the upper double-glazed window and the lower sandwich panel. In this case, the masters agree with the purely aesthetic function of the element.
Another thing is completely glass balcony doors (in cases where the glass goes from the threshold to the uppermost slope). Here the purpose of installing the impost is completely different - to correctly distribute the weight of the double-glazed window.
Here you can not do without calculations. Let's take the standard numbers: the height of the balcony door is 2.2 m (in general, in apartment buildings it is difficult to find balcony openings whose height would be less than 2 meters), the width is 70 cm.
Hence the total area of the balcony door is 1.54 m2. Standard (with two chambers)a double-glazed unit with an area of 1 m22 will weigh 35 kg. It is easy to calculate that the weight of the required structure in our case will be almost 54 kg.
Window manufacturing companies that care about the quality of their work will not undertake to install one-piece window structures than the weight is close to the limit - 55 kg. In some cases, with the insistent desire of the customer, the installation takes place, but without giving any guarantees.
Therefore, the only correct way out of the situation is to install a horizontal impost. The element will take a few kilograms off the weight of the door, as it is much lighter than double glazing. In addition, it will help to properly distribute the weight of the latter. The third plus: the installation of two separate double-glazed windows is always more reliable than one solid one.
Decorative elements
The installation of imposts that perform only an aesthetic function is a rather rare occurrence. The element is more in demand for practical purposes, fastening fittings.
Deaf sashes are mostly separated by a decorative impost. It symmetrically delimits the double-glazed window, draws attention to the correctness of its shape. The weight of such a deaf sash can be completely different. Since it does not open, is not equipped with fittings, this eliminates the risk of sagging.
The size of the profile in such cases will correspond to the size of the window frame. The depth varies between 58-70 mm.
One of the decorative varieties can be considered a false impost. Its second name is shtulp. Aboutelement we have already described above.
Impost is one of the important elements of window construction. Outwardly, it resembles a horizontal or vertical crossbar. Allows you to divide the window into parts for the installation of sashes and blind double-glazed windows, helps to distribute the weight of the glass mass, and gives additional rigidity to the structure. In addition, it can perform purely decorative functions.
