Proper installation of dobors and platbands on the front doors. Doorway without a door: finishing methods, sizes and shapes, design options Do-it-yourself arch from an additional board

An arch of extensions and platbands is one of the ways to decorate input structures. You can cope with the installation yourself without thorough preparation. You only need to choose the details of the block that match the color and style of the interior. It is also better to prepare the necessary equipment and materials for work in advance.

Doborki are special wooden, plastic or metal strips used to mask door slopes. Installation of additional elements is provided in cases where the wall thickness exceeds the width of the box. Extensions are built into areas with a bare wall, extending the box of the input structure.

Important! Platbands hide the ends of the panels, cracks and seams between the wall and door block. Plates with built-in cable channels are designed for wiring that can be hidden. Such elements are made of plastic and consist of two parts. The first is built into a wall or a box beam, the second acts as a cover, behind which the wires are located.

The color of the decorating parts is selected to match the canvas and the box. It is recommended to purchase all additional parts complete with a box in order to choose the right shade the first time.

Advantages

The main advantages of framing openings with extensions and platbands:

• simple and economical installation technique;
• emphasizes the status of the owner of the premises;
• decorates the interior of any style;
• during installation, liquid solutions are not used, which adversely affect the door block;
• the facing material helps to increase the service life of the input structure.

What will be needed for finishing?

To finish the doorway, you need to have a small repair kit on hand, consisting of the following tools:

• roulette;
• hammer;
• construction square;
• masking adhesive tape;
• tape for framing the edges of the strap;
• mounting foam;
• electric saw or jigsaw;
• saw with a miter box;
• fasteners in the form of liquid or ordinary nails and self-tapping screws;
• ready-made or homemade boards.

If the plans are only to close the slopes without replacing the door leaf, the following materials will be useful for the manufacture of extensions:

• wood boards;
• pieces of wood-fiber sheets (MDF);
• several long strips of chipboard;
• plastic items.

When cladding with natural wood species, it is recommended to pre-treat the surface with a special impregnation. The antiseptic composition retains the properties of the material for many years of operation.

Attention! By external characteristics, resistance to moisture and temperature fluctuations for finishing external entrance openings wood or MDF panels are more suitable. Indoor use of chipboards is allowed.

When installing plastic inserts, it is better to use panels with a metal base.

Finishing the opening with extensions

Camouflage elements are easier to mount in grooves. To do this, at the stage of buying a box, you need to pay attention to the presence of ready-made holes into which an additional bar is pushed.

In the absence of grooves, more scrupulous work or qualified assistance will be required. In such cases, the boards are fastened closely to the nearest millimeter. The slats are adjusted to one another and are built in as carefully as possible.

into the groove

The arch from the extensions is mounted in several stages. Installation of inserts is carried out after fixing the box in the wall.

Step by step description installation work:

1. Careful measurement of the distance from the box to the edge of the opening.
2. The width of the additional element is determined as the sum of measurements of the width of the slope and the depth of the groove.
3. Additional bars are specially bought a little large sizes to adjust the element's width to fit the right dimensions during installation.
4. Planks are built into the grooves.
5. When assembling telescopic elements, the structure is fixed liquid nails or adhesive. The parts are connected by deepening the spikes into the grooves.
6. The horizontal bar is attached to the side bars at a right angle, forming a U-shaped structure. For precision work, use adhesive tape to fix parts.
7. Before filling the gaps with foam, temporary spacers are installed between the planks to prevent the extensions from being squeezed into the passage.
8. Excess foam is removed after complete drying.

Important: each slope is measured separately in at least four places.

Without groove

The portal from the extensions in the absence of slotted holes is performed in the following order:

1. Correction of planks according to measurements.
2. The edges must be finished with edging tape. The side with glue is placed on the edge of the plank and ironed.
3. At the ends of the elements, nails are driven in half the length with the same distance between them. Hats need to be bitten off, forming sharp ends. If you plan to strengthen the block with glue, three fasteners on the side rails and a central one for the top are enough.
4. Install the horizontal extensions first, then the vertical ones. After driving in the elements, it is necessary to make sure that there are no gaps in the resulting structure.
5. The gaps in the opening are eliminated with foam.

Finishing the opening with platbands

The fastening of the platbands can be started after the foam has dried between the box and the wall.

To calculate the length of the side trim, you need to add the measurements of the width of the top to the height of the box. The upper parts are sawn with a joiner's miter box (45 degree angle). From below and in the middle, the platbands are fixed with nails.

The edges of the vertical board are also formed at an angle for the joint. To do this, it is necessary to attach the casing to the place of attachment and apply markings for sawing. Further, all the platbands are joined, fixed with nails, followed by the removal of hats in order to hide the fasteners as much as possible.

In the case of using self-tapping screws, you will need to pre-drill the recesses for the hats. Twisted screws are hidden under plastic plugs.

Installation of telescopic parts is carried out using a comb built into the grooves on the extension. To strengthen the joints between the parts of the block, glue is applied. The lower part of the architraves rests on the floor, joins the plinth on the side.

In most cases, you can install the arch from the extensions and platbands with your own hands. If structural elements are purchased separately, some points should be considered:

1. Before starting installation work, it is recommended to level the wall.
2. Do not save on the purchase of edge tape. On the processed edges, installation errors will not be noticeable.
3. Edged ends protect the material from deformation in rooms with a high level of humidity.
4. Parts of the telescopic type are best purchased ready-made. For self-manufacturing special fixtures are required.
5. Aluminum platbands are fastened with self-tapping screws.
6. In the presence of a metal door, all elements are fastened by welding.
7. A layer of insulation can be placed in the gaps between homemade additional boards and the wall. This layer improves thermal insulation properties, prevents the penetration of extraneous sounds.
8. It is possible to achieve sealing of slopes with the help of silicone inserts in the grooves of the box beam.
9. IN metal structures gypsum boards are used for mounting the doborka.

Important: the thickness of the additional boards should not exceed the width of the grooves of the box.

Finishing doorways with extensions and platbands completes the framing of the opening for both entrance and interior doors. Additional elements give a complete look to the whole door structure.

When ennobling the opening of the entrance or interior door, the peculiarity of its design is taken into account. The presence or absence of a sash affects the choice of material. There are many options for finishing the doorway, but when implementing a design idea, one must take into account the harmonious combination with the interior of the entire room.

To choose the right solution for a doorway, first consider its shape. The front door is traditionally associated with a rectangle. Interior rooms in the absence of a sash are given curly configurations.

Classic

Classic style technology allows you to ennoble the passage between rooms without affecting its shape. A traditional rectangle, with or without a sash, is lined with platbands. For finishing wide slopes, extensions are used. As platbands, you can glue a decorative corner. Stained glass windows look beautiful doorway, from multi-colored glass inserts.

Arch

The arched shape is considered the most popular way to decorate an opening without a sash. Its merit lies in smoothing sharp corners. Smooth transitions of the upper part of the door structure allow you to beat the imagination. In low rooms, the arch visually makes the ceiling higher, and in high rooms - lower. The effect is achieved due to the size of the structure. The more the arch expands, the lower the ceiling appears.

Arched wood frame looks rich doorway between rooms. In the budget option, you can use plastic or MDF. Arches usually separate the hall from the kitchen or hallway, and are also used when combining an insulated loggia with a living room.

Trapeze

Not a very popular form for decorating a passage in a partition, especially in a small apartment. Sharp corners will make the room uncomfortable. Trapeze fits wide doorway V big apartment, A the best option facings - materials of light and warm shades. in the house with low ceilings it is undesirable to make a narrow upper part of the trapezoid. A small jumper will visually lower the ceiling, reduce the room and give the interior a heavy look.

Asymmetrical shape

For achievement modern interior, the design of the room is often associated with the idea of ​​arranging an asymmetric opening on interior partition. Construction stores offer ready-made kits. When implementing your idea, a bizarre shape is created with a galvanized profile, and sheathed with drywall on top.

Asymmetric configuration suggests the formation smooth transitions V different parts designs. Avoid sharp corners. Finishing is usually done by painting or wallpapering.

Curtain decoration

Free passage between rooms without a sash is decorated with a screen or curtains. This is the most affordable way decorations. Curtains made of fabric look cozy. Unusual interior create thread curtains. In the "eco" style, the room is decorated with bamboo curtains.

Materials for finishing the doorway

Plaster

Gradually losing popularity, plaster is used as budget option when you need to arrange a doorway for painting or wallpapering. The disadvantage of this method is the complexity of the work and a large number of mud. If the technology is violated, the formation of cracks and even shedding is possible. In stores, plaster is sold in the form of a mixture. The composition is different. The method of preparation and application to the wall depends on the type of plaster.

In outline Finishing work consist of the following steps:

• Mix the solution in the container. The amount of one batch is calculated for half an hour of work.
• The solution is thrown onto the surface of the wall, distributing it with a rule and a spatula.

• When applying a thick layer of plaster, beacons are used. Guides will help to perfectly level the surface.
• So that a thick layer of plaster does not crack, after applying 1 cm of mortar thickness, a reinforcing mesh is laid.

Decorative plaster can be painted. If this rough finish, then the surface is covered with textured putty.

Drywall

Finish the doorway with drywall in two cases:

• when changing dimensions or shape;
• if you just need to sheathe the opening instead of plaster for subsequent finishing.

To create figured openings, a galvanized profile is used. First, a metal structure of the required shape is assembled, and then it is sheathed with plasterboard.

Drywall can be used to correct large irregularities without changing the shape of the opening. The slopes are sewn up with sheets, and the corners are aligned with a profile.

After installation, the GKL surface is primed. Seams, protruding caps of the self-tapping screw and other defects are sealed with glue with a sickle lining. After the surface has dried, a layer of starting putty is applied. If it is not supposed to paste the opening with wallpaper, but painting, apply another layer finishing putty. After drying, the surface is rubbed with a sanding net.

MDF panels

The advantage of finishing the MDF doorway is that there is no need to additionally prepare the surface by applying plaster or plasterboard sheathing. Wide choose colors allows you to choose the material even under the old metal door. When the door slope is sheathed with MDF panels, the total thickness of the cladding is taken into account. It should not interfere with the opening of the sash.

Installation is carried out on the frame. The structure is assembled from a metal profile or wooden slats. Attached to the wall with dowels and screws. Sheathing starts from the top crossbar, then goes to the side slopes. The joints at the corners are sealed with a decorative strip matched to the color of the panels.

Plastic

door trim slope pvc plastic panels similar MDF sheathing. However, the disadvantage of the material is its brittleness. The sheathed frame creates cells with voids between the slats. Near the door, someone will definitely press the slope with their hand and the lining will break through.

PVC panels are best glued with liquid nails. The color is selected with imitation of natural materials, most often wood. Nice classic white. Glue the panels on a perfectly flat surface, pre-finished with plaster or drywall. Before installation, the back of the plastic is rubbed sandpaper. The roughness will provide better adhesion to the adhesive. Joints on internal and outside corners hide the corners.

Laminate

To beautifully finish the door slope with a laminate with your own hands, you need to choose the right material. The color of the panels is selected so that it matches the shades of the doors, floor covering and even skirting boards. The slope, which stands out in contrasting colors, looks tasteless.

Fix the laminate in three ways:

1. On a perfectly flat surface, the panels are glued with liquid nails. The process is identical to the installation of plastic. Slopes are first plastered or sheathed with plasterboard. Laminate begin to glue on upper crossbar, then move to the sides.
2. Mounting on the frame allows you to lay thermal insulation in the cells. Simultaneously with the finishing, the opening is insulated.
3. Gluing with mounting foam is similar to using liquid nails. The difference is that there is no need for a perfectly flat base. The foam itself will even out the flaws when it swells.

Facing made of high-quality laminate will last up to 20 years.

Decorative rock

IN modern apartments oh fashionable doorway trim decorative stone, which does not differ in appearance from natural material. Facing is best done with small elements with a weak relief. The design of doorways with a decorative stone with a deep texture inside the room creates the effect of a bulky structure.

A variety of material allows you to embody bold design ideas. Imitation looks good on the entrance door slope brickwork. Fans of the classics are offered elements with the texture of clinker tiles. To finish the corners of doorways, there are special corner plates that eliminate the need to cut stone.

To get a beautiful door slope you need Smooth surface. Elements are glued with liquid nails. The resulting seams are covered with grout.

Polyurethane

The elements used to frame the doorway made of polyurethane have completely replaced the gypsum moldings. Lightweight and durable material sticks well, does not break when dropped, and is resistant to moisture. The resulting seams are covered with putty, and after they dry, they are rubbed with sandpaper. Polyurethane stucco is suitable for rooms with high ceilings.

Dobory

To finish the doorway with extensions, they buy a kit. It consists of wooden or MDF planks. When assembled, a product is obtained that hides slopes protruding beyond door frame. The end result is a complete structure.

There are three types of extensions on the door slope:

• simple;
• with an edge at the end;
• telescopic.

The first option is a plank with a raw edge. Tape-edged extensions allow you to hide the uneven edge in case of installation flaws. Telescopic boards are equipped with mounting grooves.

Tile

Finishing the door slope with tiles is justified if the material is in harmony with the design of the walls. The option is optimal for a bathroom or kitchen. Tiles are produced in various shapes, which allows you to veneer not only rectangular areas, but also arches. For styling ceramic tiles you need a flat hard surface. Installation takes place on the adhesive composition. The joints are covered with decorative grout.

Gypsum

Decoration of the doorway plaster molding is rare. The material is quite brittle and heavy. In case of poor fastening, the falling element will break, and can also injure a person. To make it work beautiful decoration doorway, there should be a lot of plaster, and one style should be observed. This can only be achieved in a large spacious room with high ceilings.

Wallpaper

The simplest and old way- This is to glue the wallpaper on the slope. Moreover, the door leaf itself is often pasted over. Wallpapers are selected high-quality, resistant to abrasion and dampness. If you are finishing with photo wallpaper, the opening can be designed in the form of a living corner. To hide the doors from view, the slopes and canvases are pasted over with the wallpaper that was used for the walls. For contrasting highlighting, the sash is partially pasted over with patterns. Acceptable geometric figures or fragments of a picture.

Doors and objects adjacent to them are considered the hallmark of the house. It is not worth saving on the design of this site, because it first of all catches the eye of guests.

A beautifully designed doorway always looks neater and gives the whole room a finished look. It's hard not to notice how much it changes when it is framed. And the point is not only that they hide all the nuances of the installation process, but also that the opening becomes more pronounced and noticeable. Very often, designers specifically pay great attention to such a finish. As a result, they get a unique and often unique element of decor in their execution. Increasingly, you can also find openings in which there are no door leaves. Sometimes this is also a deliberate move by designers, and sometimes it's just a necessity. Today we are going to look at the questions design of a doorway without a door. Consider when it is appropriate to leave the openings open, and what disadvantages and advantages such a solution entails.

1. Open opening - a design move or a necessity?

doorways open type increasingly can be found in the interiors of modern apartments. Sometimes this is really a design technique, which is designed to bring originality to the overall atmosphere. But more often than not, this is a very sure move in visual terms. expansion of space and save space. At the same time, no one says that such an opening cannot look interesting and unusual. Standard swing doors take up a lot of space, especially if they open inward. Depending on the width of the opening, the door can "eat" up to 1 square meter total area. Instantly appear restrictions on the placement of furniture or decorative elements and a host of other inconveniences.

Sometimes they are used instead sliding structures, which are undoubtedly much more compact. However, they do not always look aesthetically pleasing. If the door guides are not enclosed between the walls, they must be mounted on one of them. Thus, appearance walls in one of the rooms may look spoiled. Therefore, in some cases, it would be appropriate to decide on the dismantling of interior doors. At the same time, the line between two adjacent rooms is automatically erased and a single space is formed.

Sometimes it really appropriate, For example:

• In case of increasing the size of the room by attaching a balcony or loggia to it. In any case, such actions are accompanied by the dismantling of the balcony block, otherwise the whole plan will not be realized;
• If you plan to combine the living room and hallway. The organization of an open-type portal in this case will blur the line between two rooms that are completely different in purpose, but at the same time maintain a conditional separation. Living room small size at the same time it will seem much more spacious;
• If you have organized in the bedroom, while sacrificing the size of the bedroom, it is better not to use blank door panels. Leave the opening without doors, and we will teach you how to beat it beautifully.

Many people use a similar technique when joining the living room to the kitchen. Most often, the opening is performed in the form of various shapes. Undoubtedly, this is the most aesthetic way of combining. But do not forget that if you use the kitchen for its intended purpose and are actively preparing food, then all the smells that accompany this process will instantly spread throughout the apartment.

Also not quite right the solution is to dismantle door panels in the children's room, bedroom or office. All these rooms require separate space. Of course, the exception may be the case when you live alone and, in principle, there is no one to retire from. In all other cases, doorways without doors can expand the space. Therefore, they are especially common in small apartments.

2. Advantages and disadvantages of doors without doors

After we figured out when it is advisable and when not to use free doorways, it's time to talk about the clear advantages and disadvantages of this technique. Let's start with disadvantages:

• When dismantling door frames there is no clear distinction between where one begins and the other ends functional area . On the example of combining a kitchen with a living room in a similar way we realized that this is not always appropriate. Of course, there are exceptions. For example, when you visit the kitchen in the morning to make yourself a coffee or in the evening to have a light snack. However, this same blurred border effect can be an advantage in other cases;
• If we take into account that the lack of secluded spaces for a person who lives on his own is not critical, then all the same there are rooms in the apartment where doors are simply necessary. For example, in bathrooms. This lack of open openings is not critical, however, it takes place.

Now let's talk about benefits portal organizations:

3. The choice of the shape of the opening, depending on the style of the interior

Before you choose how to design a doorway, you should also think about its shape. Of course, you can leave everything unchanged. And rectangular open portals look very impressive. And you can try pick up the shape opening, focusing on interior in the room. After all, the opening should harmoniously fit into the overall picture and emphasize its features. Consider the most suitable different styles forms:

• Chic destinations such as rococo or renaissance imply a predominance of symmetrical, regular lines. This simplicity is compensated by a large abundance decorative elements. It can be complex carvings, various stucco moldings with gilding, or complex arched bas-reliefs;
• Discreet and noble classic style best complement the arched type openings. In this case, the arches are preferably oval, three-center or semicircular in shape. Of course, the classic is not complete without such material as wood, which can be decorated with decorative carvings or milling;
  
• Eastern directions arched openings are also preferred, but their shape may be more varied. They can be lancet or keeled, in the form of a heart or a circle. In general, in this case, you can give free rein to your imagination and focus on the shapes and silhouettes of pieces of furniture;
• romantic destinations do not overload with complex bends. All elements in them should remain light and airy, smooth and graceful. Semicircular sloping openings without sharp transitions are ideal. At the same time, you should not abuse the amount of finishing materials and choose their rough and heavy options;
• Modern and concise styles, such as, or techno, recognize only strict regular geometric shapes. There can be no talk of any ovals. Strict symmetry must also be present. Therefore, in this case, it is better to leave the shape of the opening unchanged and only carefully align all the corners and edges;
• Such interesting and extraordinary directions as or pop art must have in the interior a subject very unusual shape. Usually this is a small piece of furniture, for example, an armchair, chair or. But why not show your imagination and create a winding, asymmetric opening? It is this decision that will best complement and emphasize the stylistic affiliation of the room.
  

Choosing the most suitable form, you should lean not only to the above recommendations, but also to ceiling height in room. Otherwise you risk once again draw attention to the existing shortcoming.

When choosing this type of finish, remember that natural wood requires careful maintenance. And the rest, it all depends on your financial capabilities and imagination. The color of wooden openings should be coordinated with the color of the floor or skirting boards. You can also rely on the color of furniture.

The style also plays a role. After all, not all modern trends welcome the use of such "warm" materials. For example, or minimalism is more preferred by plastic or metal.

12. Decorative finish with natural or artificial stone

When choosing a finish with natural stone, it is necessary consider his weight and select an adhesive mixture specifically for such material. In addition, the installation is further complicated by the fact that the fragments can slide under their own weight, so either it is necessary to lay them using the same technology as using a piece of a metal profile and wedges, or hold each pebble for several minutes until the glue grabs.

Also, some experts argue that laying should start right from the floor, but this is not always appropriate. For example, if you want to use skirting boards, it's better to leave room for them than to mount them on top of rocks. Natural stone is expensive material. Therefore, very often preference is given to an artificial substitute. His appearance is enough high level imitates natural texture. It is lighter and more affordable, easier to install and cut. And to further facilitate the process, they came up with ready-made corner elements.

Doorways lined with stone look very cozy. However, you should not choose a similar finish for deep and narrow openings. It may turn out that the opening will resemble the entrance to a cave, which is far from appropriate in all interiors.

13. Arch instead of the usual "rectangle"

Arched openings have become popular for a very long time and are still actively used by many designers. Doorways of a similar shape are Very good decision for use in small spaces. They help to visually make the space more spacious. And the right proportions of the width and height of the arch can “raise” a low ceiling. Arches can be both standard forms and the most unpredictable.

Very often, such an element is a key element in the interior, and all the decoration depends on it. You can purchase ready-made arched portals from the most different materials, Can i do arch on one's own. Often, the frame of the desired shape is mounted from metal profiles and covered with drywall. Instead of profiles, wooden planks of sufficient thickness can be used. A layer of plaster is applied on top of it, and then decorative trim. Very often arches can be found as connecting element loggia between the room. They may have built-in shelves, lighting, niches for placing decor items or a fragment. It can also be used as a dressing table or place to place indoor plants. Advantage the design of the doorway in the form of an arch lies in the fact that it can fit into almost any style of interior. It is enough just to choose the right shape and finishing material.

And for creation various functional elements. It can be a composition of wall niches, or it can be a homemade rack. The space around the doorways is often empty. If you equip shallow drywall shelves around the perimeter, you can save space, provide enough space for souvenirs, books, family photos. In this case, the need to purchase a wall or cabinet may disappear automatically.

In addition, such structures can frame openings not only of rectangular, but also of semicircular shapes. This solution looks very original and interesting. Subsequent drywall finishing will depend on the style of your room. It will be possible to simply plaster and paint the surface, choosing a color according to wall covering. Separate shelves can supplement colorful backlight. Back walls shelves can be pasted over or painted with a distinctive color.

This will give the design originality and make it visually deeper. From drywall, you can build, probably, absolutely any shape of the structure. The main thing to remember is that it should not be loaded with heavy objects. Still, such elements are more decorative in nature.

15. Making a doorway with textiles

Making doorways with the help of textile elements can be called the most romantic of all ways. A translucent tulle that blows in the wind will create a stunning atmosphere, especially if you choose a fabric with a barely visible shiny thread that will shimmer in the sun. It is with the help of curtains that you can create a design that, if necessary, will create a secluded atmosphere. If, nevertheless, you decide to connect the bedroom with the living room or another room, then choose opaque curtains with side pickups to decorate the doorway.

In addition to the usual transparent or opaque fabrics, filament curtains, curtains made of bamboo or beautiful beads are perfect. You can create complex compositions from several types of fabrics with lambrequins and other elements. Such a volumetric design is appropriate only in large rooms and for wide openings. The room in which the door and window openings are decorated identically looks very interesting.

The only thing you should not do is to choose roller or Chinese curtains or vertical fabric roller blinds for decoration. Passing between rooms in this case will be very inconvenient.

What is a concession and why is it needed? What are extensions or, more correctly, "additional strips"? These are strips with a width of 5 cm or more (depending on the manufacturer) and a length of about 214 cm or even 240 cm. Classically, the trim is selected to match the trim, the door frame and the door itself, if this does not go against the designer's idea.
When are fees set? Fees are set in two cases:
1. In the event that the thickness of the door frame is less than the thickness of the wall.
2. For framing a doorway (upgrading). For the greatest clarity and understanding of the moment, look at the photos below, which show the option of installing a door with an extension and the option of installing a door without an extension:

Framing the doorwayorom(portal).
The photographs below show what a doorway looks like, framed by extensions and a platband.


Look, evaluate and decide if you need extras in your case. A matter of taste. The cost of installing the dobor
is not so great that it can be neglected and close one's eyes to the important functional load that the extension bears during operation.
A little more about this:
Since doors are usually installed on long term, then the functional load also falls on the extensions: what if not the extension will protect the slopes from “loading” and “scuffs”? This happens over time with the "unprotected" doorways, while behind the doorway, framed in accordance with all the rules, care is simple and convenient. By the way, about how to care for your new door, do not be too lazy to read the manufacturer's instructions. By following the simple rules of operation, you can provide your door with an impeccable appearance, and it will serve you faithfully for many years.
And so we begin to ennoble the opening:
The most important thing is to get it right! We measure with a tape measure (in no case with a measuring tape or ruler!). We measure the thickness of the wall on the sides and at the top SEVERAL times in different places. Why we do this - to avoid expanding the wall, and not to buy extensions that are narrow for our opening. We measure the height and width of the opening in the same way, in several places. We go to the store and choose the material and color that you need. The manager will tell you what size of extensions and trim should be purchased - based on your measurements. DON'T FORGET TO TAKE THE MEASUREMENT WITH YOU!
Extras are different:

• regular chipboard or MDF
• ordinary chipboard or MDF with an edge at the end,
• telescopic.

to install telescopic dobor, you should have experience and a tool - so it's better to turn to specialists.

If the additional bar does not have a groove, then it is fixed closely. Installation by this method requires careful fitting of the planks. The elements should be cut strictly in size, if extra millimeters are noticed after sawing, then they are removed with a planer. An edge is glued to the cuts (if desired, of course, but the finished opening will look more aesthetic with it) iron to glue with reverse side heated up and melted. Only in this case, the tape will firmly attach to the extension. Thin nails are hammered into the ends of the plank at a distance of about 25 cm, no more. But if “liquid nails” are used, then three nails are enough to secure the vertical bar, and one or two can be used on the horizontal bar. In this case, the hats from the nails must be removed so that the edge is sharp. The side strips are installed first, and then the horizontal part is placed. Press the vertical extension against the wall in the lower part, do not hit the fastener hard, and then hammer it to the end so that it completely enters the box. In the same way, fasten in the middle of the bar and at the top. It is necessary to ensure that no gaps appear between the door frame and the placed extension. Put the horizontal part of the extension on the side ones, check the accuracy right angle and then finally fix with nails. After correct installation nails are invisible. The gaps that have formed are foamed. Put the horizontal part of the extension on the side ones, check the accuracy of the right angle and then finally fix it with nails. After proper installation, the nails are invisible. The gaps that have formed are foamed.

Platband installation:

After the work on the installation of the extensions has ended, they begin to fasten the platband. First, measure the height of the side rails. But to this size add the height of the horizontal bar at the top. You can dock a flat casing in several ways. A common method is when platbands are attached at 90 degrees. In this case, the shape of the joints will be the same. If the corners of the slats are sharp, then they are installed without adaptation. For rounded corners, you need to narrow the top trim a little. Of course, it is best to install a radius platband - to install the good old method - at 45 degrees. Pictured below are both options.

You also have the opportunity to install in the opening not an additional element and a platband, but pilasters and a capital, various figured cornices and platbands, a cartouche, carved "thrust bearings" and rosettes. All of this can be patinaed or not. Here, of course, one piece of advice - installation should be carried out only by specialists !!!
Photos of such openings below: