Well      04.03.2020

Do-it-yourself round steps. How to pour a semicircular concrete porch at the entrance to the house. Production of a concrete porch - we prepare materials and tools

IN Lately noticed a strange trend: almost all architectural details and elements are simplified by designers and architects towards straight lines. This trend runs like a red thread in almost all structures, including porches. The maximum that can be seen is a trapezoidal shape. I propose to challenge the routine and try to do something more aesthetic.

An excellent option to break out of dullness and routine would be a semicircular porch. It can be made from any building material suitable for these purposes - concrete, ceramic brick, wood, plastic compound. I chose facing ceramic bricks and have never regretted it.

First of all, you need to determine the general concept of the future porch, which depends entirely on your design talents. In addition to aesthetics, the concept of the porch is also influenced by its geometric dimensions and the height of the rise. In my case, it turned out three tychkovy rows with a small caveat: the third row did not fit on the bed, but on the spoons. Thus it turned out pretty original look. But first things first.
As mentioned above, the first row is made of brick quarters, for unconditional repetition of a rounded shape. To control a specific radius, I came up with not a tricky device.

It looks very simple and probably ridiculous, but the fact remains that the measure is extremely accurate. The main thing is to fix it qualitatively. However, this must be done in such a way that it can be freely moved from one end to the other.

For execution brickwork we need a basic set of mason's tools:

  • mason's hammer;
  • trowel (trowel);
  • a mallet with a rubber "head";
  • scraper;
  • level (length according to circumstances);
  • roulette;
  • bucket;
  • "Falcon" plaster for mortar (can be replaced with a piece of plywood, like mine).

So, let's get down to the homemade steps of the porch. Jitters to the side, trowel in hand. First of all, you need to prepare the material for the entire first row and install it “dry” in the design position. Thus, in the future it will be easier to install the brick on the mortar and the selection of the necessary fragments will not take much time. After that, we install one of the bricks central along the front on the mortar and align it according to the level.

Before laying a brick on the mortar, you need to prepare the base: if it is concrete, like mine and it is quite warm outside, then it must first be moistened with water so that the concrete does not take water from the mortar until it gains strength.

After laying the first outer row, the second inner row of quarters is laid out. After that, the second outer row of quarters is laid out. The main thing is not to forget one of the basic rules of masonry: the seam of the overlying row of bricks should not fall on the seam of the underlying one, that is, saying plain language, the seams should go in a checkerboard pattern. The second inner row can be made from a whole brick; it does not affect the geometric shape in any way.

Well, the simplest thing is behind, it remains to complete the main row that completes our composition. As mentioned above, the third row is not quite ordinary. But even such an elongated shape is also not enough to make a beautiful symmetrical semicircle. There is only one option - to make the steps of the porch from a rectangular brick, a brick having the shape of a trapezoid. In order for each brick to be the same size, a template is made.

According to the template, the required number of bricks for the finishing row is marked. The segment of the "extra" is performed by a manual cutting machine (grinder) with a diamond wheel.

It is advisable to use a large grinder with a circle diameter of 230 mm, then the probability that the brick will be cut to the base is around 100%.

The rest depends on your skill.

Having prepared the material, we proceed with it, as with the previous rows: we set it “dry” in order to completely fill the entire semicircle.

Good preparation is the key to 100% success. We prepare the mortar and carry out the laying of the front upper row on the mortar in the design position, not forgetting to control the evenness of its installation.

The wall of the porch has been erected, it remains to fill its inner void! After some deliberation, preference was given to porcelain tiles. For it, you need to fulfill the foundation. Concrete is not a cheap pleasure, so the bottom two rows of bricks are best covered with ordinary sand. The drainage tray is simply covered with a plastic film, which is additionally laid under the entire base of the porch.

Next, sand is backfilled, which should be done in layers with careful compaction of each layer. If this is not done, then over time it will compact itself and sag. In this case, the entire upper "pyrgo", including the facing coating, will sag along with it.

After preparing the base, it's time to start preparing porcelain stoneware. Using a tape measure and a compass, we take measurements and transfer them to the tile. We cut off the necessary segments with the same grinder with a diamond wheel. A tile cutter in this situation is unlikely to help. We try on "dry" cut pieces of tiles. I think they fit perfectly!

Final chord! In order to avoid capillary backwater from below, we spread it on a sandy base polyethylene film. We prepare the solution and evenly stretch it over the base. It is best to use a plaster floor for this.

The thickness of the mortar should be such that a distance equal to the thickness of the porcelain stoneware slab remains to the top of the brickwork.

Carefully lay the fragments on the solution and leave alone until the solution completely hardens.

Almost completed, the last touch remains - we put the seams and enjoy our little masterpiece!

Among unusual shapes the porch is most often found in a semicircular shape. It is convenient in everyday use, does not require special materials and is always liked by customers. At first glance, it seems that a semicircular porch is not difficult to lay out of brick or cast from concrete with your own hands. If you have at least some experience of such work, you will surely be able to build one of the options shown in the photo.

Which option to prefer

The actual ways of making a semicircular porch are as follows:

  • Cast a semicircular concrete porch frame with further finishing and cladding;
  • Fold from brick and ceramic tiles;
  • Build a porch from rubble stone with finishing of the entrance platform and steps.

If it does not work out, then you can use the scheme for using the boot suggested in the video

In fact semi-circular porch designs built by a professional hand can be very beautiful, even in the most ordinary houses, as in the photo.

Semicircular porch made of concrete and brick

A porch with semicircular steps made of brick looks no less interesting than any other design, photo. The type of stairs and entrance platform largely depends on successful combination with elements of the facade of the house and even masonry walls, as in the photo.

The fastest way is to build a semi-circular porch from ready-made concrete blocks or clinker. In concrete casting, many finishing operations, such as laying tiles on steps and entrance areas, are limited by the “ripening” of concrete. Only after a month you can start laying ceramic tiles.

In all variants of manufacturing a porch with semicircular steps, it is necessary to perform preparatory operations:

  1. Dig a ditch - a foundation pit for the porch foundation. At the same time, we will definitely make a gap between the foundation tape of the building and our casting, and we will not connect both foundations into one;
  2. Make high-quality waterproofing from several layers of roofing material glued with resin mastic. We will lay the waterproofing on a sand and gravel filling at the bottom of the foundation and fill it with a thin layer of concrete;
  3. We will install short vertical sections of steel reinforcement and long horizontal pieces in the foundation for the entire length of the pit;
  4. Zalem foundation under a semicircular porch to the ground level.

We cast a semicircular frame under the porch to the house

In home construction, pouring concrete mortar of any, even the most complex forms, is a process that has long been worked out and studied to the smallest detail. Before casting a semicircular frame, it is necessary to accurately measure and calculate the required amount of reinforcement for laying the steps in the base.

Oddly enough, but the main difficulty in casting non-standard semicircular steps is not the amount of concrete work. It is difficult to guess and bend exactly along the radius of an 8 mm rebar more than two meters long. The easiest way was suggested by the guys in the video

But you can do it in a more traditional way and bend steel bars with a sledgehammer.

Before installing the formwork, we connect the reinforcement into one steel frame of the steps and install a dimensional template under the steps, as in the video

or in the photo.

Each of the horizontal rods must be leveled in height, and only after that proceed with pouring concrete. While the concrete has not hardened, do not forget to plan a slope on a semicircular surface for the water to drain.

The brick version of the porch can be folded faster than cast from concrete, but you must remember to tie the masonry to the reinforcement released from the foundation. Brickwork is carefully leveled on the horizon. Sometimes masonry is performed on white or black colored cement, which increases decorative properties stairs. Ordinary masonry from ordinary clinker brick can veneer good paving slabs or even artificial paving stones.

Facing bricks can be painted or treated with a water-repellent solution.

Cladding with ceramic or clinker tiles

Before facing work, we overwrite and clean all protrusions or defects and prime the prepared semicircular surface with a special compound, for example, Ceresit CT17. It will improve adhesion with the adhesive mixture on which the tiles will be laid.

There are two main methods for laying tiles:

  1. The usual in-line method, in which the tiles are laid on the surface of the entrance platform and steps of the semicircular porch in the same sequence as for conventional rectangular structures, as in the photo. Edge tiles are cut on the machine to obtain the desired end radius;
  2. The sector laying method is used exclusively in decorative purposes when required by the design method of the entrance area of ​​the porch. The outer edge of the tile is laid in a sector with trimming the edges of each tile to the same extent. With this method, the supporting surface of the steps, on which the human foot stands, is able to withstand higher loads without breaking off from the semicircular base.

In both cases, the tiles have to be cut. For material over 10 mm thick, it is recommended to use stationary machine with diamond circle. It does not crack and burn the facing material.

Before cladding, a dry laying of all tile elements on the base is necessarily carried out, the dimensions are adjusted individual elements taking into account the obligatory expansion joint between individual tiles 8-10 mm. Before laying the tiles, the joints with the vertical walls of the facade are reinforced with sealant.

The glue is applied to the surface to be glued with a special notched trowel, after which the tile is laid and pressed against the base by hand. The position is controlled by building level at least 150 cm long. The vertical risers of the porch are faced in the same way. The edges of the semicircular steps can be closed with a metal tape or corner.

Final stage

After a couple of days, the space of the expansion joints is cleaned and filled with a special grout. The tile can be tinted with a special dye or treated with finishing mastics that add shine and enhance the effect of the texture of the material, as in the photo.

Conclusion

A semi-circular porch is always a working porch, it is convenient to use, and hundreds of pairs of feet can pass through it during the day. A simple porch in configuration, it is increasingly being used not only for the back door, but also as a variant of the front porch to the house. A porch with a semicircular entrance platform is indispensable for both country or country house as well as in urban congestion.

Reading time: 15 min

There is a house - there must be a porch. This is an axiom, and until people have learned to fly like birds, it does not need proof. But even today experts have not come to a consensus about the architecture of the porch and the most suitable materials for its manufacture.

Therefore, in this review, we will first see what options are generally possible here, and then we will go through in detail one idea that, in our opinion, deserves attention. And we will even show you how to build a semicircular porch with your own hands.

So, Wikipedia claims that the porch is an outdoor extension with a canopy and steps. It serves to protect the front door area from bad weather and at the same time performs decorative functions.

Have questions?

Ask and receive helpful tips from professional builders and experienced summer residents.

And now, it is this last point that is important for us now. Indeed, in fact, if you do not think about beauty, then it becomes incomprehensible why these round steps are needed at all?

They are more difficult both to manufacture and operate and are much more traumatic than their rectangular counterparts. In addition, the form imposes some restrictions on the list of structural and finishing materials. In a word, for the sake of the design you like, you will have to suffer a lot.

But let's be consistent and briefly go over the entire spectrum options, dwelling only on those products that allow you to make a staircase in the form of a semicircle.

Wooden porches

Wood has traditionally been considered a versatile building material and, of course, it is used in the construction of a porch. At the same time, it can perform both structural and finishing functions there.

In the first version, timber and boards are used to create a supporting frame. In the second - for sheathing ready-made metal and stone foundations. But in both cases, the master gets the opportunity to work not only a rectangular, but also a round porch.





metal porch

A worthy analogue of wood is iron. True, a planer and an ax will not be enough to process it, but a hand-held power tool has long ceased to be a shortage. inverter welding machine or an angle grinder is probably in the workshop of every self-respecting summer resident.

And even if you have to buy all this from scratch, it's worth it. After all, steel has an order of magnitude greater strength and structural flexibility than wood, and therefore it is also possible to make a pretty, semicircular porch for a private house, or at least its frame, from it.





stone porch

And finally, the third most common building product in the field of roof construction is stone. Moreover, both natural and artificial. Booth, concrete, marble and - all these materials are united by enviable strength, wear resistance and a fair amount of weight.

And to work with them you will need glue and solutions. That is, water will necessarily be present, which in turn will require some time for its evaporation. Perhaps that is why impatient summer residents prefer faster technologies.



But this is if you mean the usual open veranda. If we consider the porch laid out of stone in a semicircle, then these will account for about 90% of all figured steps. Remember how often you saw an oval porch made of wood or metal?

On the other hand, tiled radial staircases are sure to decorate a familiar store, hairdresser or massage parlor porch. Here in this article we will consider just such semicircular steps. For a private house, a threshold cast from concrete and tiled will serve as a wonderful decoration.

Round porch and its disadvantages

And yet, before you start pounding sand with cement and knitting reinforcement with your own hands, I would like to remind you that a round porch, especially cast from concrete, is not without flaws.

  1. Injury hazard. The circle is associated with freedom and the absence of borders. But where they do not exist, there are no landmarks, and therefore it is easy to fall from semicircular steps not only in winter, but also in the dark season, especially when the “client” is drunk.
  2. Material overrun. Tiles, boards, panels - most of the traditional building materials have a rectangular shape and when building smooth lines from them, unclaimed trimmings will inevitably remain.
  3. Technology limitation. For example, you do not use aluminum anti-slip strips on oval steps, as well as abrasive belts. More precisely, you can stick them there, of course, but they will look terrible.
  4. Increased requirements for the professionalism of the master. Not every tiler will undertake to veneer a semicircular staircase. More precisely, not everyone has the necessary experience for this.

Aren't you afraid? Then we go to step by step instructions.

How to make a semicircular concrete porch

Let's start our master class with the fact that all concrete porches must be designed and cast along with the foundation of the house. Only such an approach to business guarantees the absence of cracks between the threshold and the basement of the parent building. But that's in theory. In practice, when building a house, the canopy over the front door is the last thing to think about, and the base for the semicircular steps has to be poured separately.

For example, consider the following situation.

There is a flat facade with a plinth height of 500 mm and a clean area in front of it with non-heaving sandy soil.

Since our soil is not very afraid of frost and does not accumulate moisture, we propose to build a porch on a floating, slab foundation, but before that we calculate the area of ​​the building spot.

  • So, the optimal step rise is 15 cm, so with a basement height of 50 cm you will need 3 of them. One of which will be at the same time the porch deck, and the other two will add 300 mm each to its dimensions. This time.
  • Width door leaf the entrance door is 0.9 m, which means that the platform, at least, cannot be narrower than this value. This is two.
  • front door someone must open it, and at the same time somehow miss it, and therefore, at least 30 cm must be added to the original 0.9 m. These are three.

As a result, we have a building spot in the form of a semicircle with a radius of 1700 mm. 900 mm for opening the door + 300 mm - space for maneuver + 600 mm for two steps.

To mark the desired contour on the ground, drive a piece of reinforcement under the wall opposite the center of the doorway and tie it to it desired length lacing. This will be your compass. Then remove the fertile layer of soil inside the building spot, and if it is minimal, then go deeper by 40-50 cm anyway. At the same time, carefully align the walls of the pit vertically, and compact its bottom with a rammer.

Hammer a palisade of meter-long reinforcement along the perimeter of the sample, ensuring that fragments about 15 cm long rise above the pit, but not more than this value. Along the way, with the same reinforcement, it is necessary to press a strip of roofing material against the walls of the sample, which will serve as waterproofing for the foundation.

Tie a grid with a cell of 400 × 400 mm inside the pit from reinforcement, so that its ends are hidden in the foundation of the house (you will have to work with a puncher), thus tying the porch to the main building. Net lifting height 70 mm.

Screw a fifteen-centimeter strip of OSB to the metal posts, forming the formwork for the first step, and install the top reinforcement inside its contour. The laying height of the latter should be 30-40 cm below the side of the formwork. As in the first case, we recess the ends of the reinforcement into the basement of the house.

Once again return to the formwork. Raise its ends a little so that a drain with an angle of 1-2 degrees is formed in the direction from the house, but at the same time the upper edges of the OSB are in the same plane. If this is not done now, then after making the nut, you will have to rub the beacons and organize this very slope at each step separately.

After that, fill the contour with concrete and pull it along the formwork, like a screed along the beacons.

Wait a couple of days for the step to dry out a little, and draw the contours of the next rise on it. Then drill along the perimeter of the nest markings and build another reinforcing palisade with a height of 150 mm, as before. And then wrap another formwork around it.



This layer no longer needs such careful reinforcement. If desired, there can be limited to one wire mesh.

Finally, the manufacturing technology of the third last step completely duplicates the one discussed below. The same outline drawn in chalk, the same fence made of pieces of reinforcement, the same OSB formwork.

When the porch dries out a little, cut off all the influxes from it with a spatula, seal the sink with a solution and generally cultivate the “clumsiness”. Today it is customary to glue tiles on a thin-layer composition, and not to lay them, as in Soviet times, on sand-cement mortar so everything should be smooth and tidy.

Laying tiles on a round porch

Now in more detail about the cladding process itself. It is impossible to produce it on raw concrete. Even with loss of moisture fake diamond shrinks, and therefore the clinker glued ahead of time will definitely fall off from it. Therefore, wait ten days after the construction of the stone foundation, and all twenty in wet weather, and treat its surface well with concrete contact.

The gluing of the tile itself should be started from the bottom riser, moving from the center of the arc to its ends. Simply apply glue to the pre-cut piece of tile with a comb and press it against the plane so that it is tangential to the circle. Now, if there is such a need, add glue to the sides of the tile and lay the next element next to it.

Remember, all tiles must be oriented cut down.

Now you can move on to the first step.

There are two fundamental various technologies laying tiles. The first suggests not matching the seams between horizontally and vertically laid tiles. The second, on the contrary, insists on this point. Let's say that the second method is more time-consuming, but also visually gives best result. Therefore, beat off the radially directed lines from the corners of the vertically installed tile and cut the tile selected for laying along them. Ideally, all of it will have one size, in practice, this happens extremely rarely.

This tile must be cut to the riser, leaving a gap of 3-4 mm between them.

The next vertical row must be cut not only in width, but also in length. The size of this tile directly depends on the width of the back face of the tile previously laid on the step. And the rest of the process will not differ in any way from the lining of the lower riser already familiar to you. We only add that the tile should be aligned along the upper step, and between it and the lower one leave the same, 3-4 mm gap.

The gluing of tiles on the second step and the third riser does not differ in originality. As before, the top row should be cut according to the previous one.

There are only some differences in the lining of the porch area itself. Here you should first form a semicircle of a step from a wedge-shaped cut tile, and lay the rest of the space in regular horizontal rows. Visually it will look like this.



After that, wash the threshold well, remove excess glue from the joints and fill them with waterproof, frost-resistant grout. After that, you can hang a visor over the porch and invite guests to the bride. If everything turned out like in the picture, you really have something to brag about.

And with that, we say goodbye to you. Goodbye and see you soon on the pages of the site "Modern Estate".

The rectangular shape of the stairs is considered standard, while the semicircular porch is exotic. Many people think that doing it with their own hands is much harder, which is not entirely true. It's just that in its creation there are some nuances that you should be aware of. But the result will be amazing - an elegant semicircular staircase leading to the house can easily become an object of envy and admiration.

Architectural features and porch options

The process of arranging a semicircular porch begins with a drawing. The top step should be 5 cm below the door, so you should measure the distance between door frame and the surface of the site on which the porch will be located, and divide this number by 18 (the height of the step for a comfortable step). The result obtained will indicate the number of steps. If it is not an integer, the height can be varied. Most often, an odd number is made so that it is convenient to enter and leave the house. Then calculate the size of the porch.

From the center of the door (options are possible), the distance is measured to the farthest point of the threshold - the lower step. It is calculated as follows: 30 multiplied by their total number is added to the radius of the upper step. Example: The radius of the top step is 1 meter (100 cm). Number of steps - 3 pieces. Therefore, the calculation will be as follows: 100 + (30x2) \u003d 160 cm. This means that the radius of the third, lowest step should be 160 cm.

Do-it-yourself semicircular porch

To equip a semicircular concrete porch with your own hands, you will need:

  • Site cleaning equipment.
  • Cement, sand, gravel, other types of materials - concrete can be improved.
  • Measuring devices (for example, a tape measure) to find out the height and other parameters of the stairs.
  • Fittings.
  • Concrete mixer.
  • Facing materials for design.
  • Additional accessories.

Before pouring the steps, you should check the compliance with the technology - whether the initial layer of crushed stone and sand is sufficient, whether the fittings are connected correctly, and so on. After making sure that everything is in order, you can start pouring.

To make formwork with your own hands, you need strips of galvanized metal. They are bent under right angle and set near the pegs, which are driven in along the contour of the pit, supported by a stone. Having well strengthened the boundaries of future steps, they lay reinforcement and begin pouring the foundation. After the concrete has dried (the period should not exceed 7-8 days), the formwork is carefully removed.
Good and a natural stone although it will cost a little more. But folk talents can boast and unusual options finishes. Some craftsmen manage to revet the porch with substandard tiles and even river pebbles. The tile is laid, interspersed with pebbles, and an original mosaic is obtained. Both that, and another is pasted by means of special structure. Before this, the porch is cleaned to smoothness. Facing a round porch made of concrete can and should be unusual and creative.

Final step by step instructions

The creation and arrangement of a semicircular porch includes the following stages of work:

  • Site clearing, marking.
  • Digging a pit 70 cm deep.
  • Laying a layer of crushed stone, and then sand by about 20 cm. Then they should be filled with water and compacted as much as possible.
  • Close the foundation of the house with roofing material with special impregnation.
  • Drill it and insert fittings.
  • Set up formwork.
  • Lay down aerated concrete blocks to the bottom of the pit, to make reinforcement.
  • Fill the structure with concrete.
  • Repeat the steps with reinforcement and pouring according to the number of steps.
  • Cover the resulting steps with a film or roofing material, periodically sprinkle them with water.
  • After complete drying, remove the formwork, clean the surface of the porch and veneer to taste.

More detailed information can be gleaned from training videos. When the semicircular porch is ready, you should appreciate how stylish it looks with almost any building.

Concrete porch of a semicircular design - perfect option for a private house. It is durable, resistant to damaging factors and correct design and calculation significantly improves the appearance of the whole house.

However, in order to make a semicircular porch with your own hands from concrete, you need to have an idea about the basic construction operations to be performed. Therefore, we will consider them in detail below.

For those who have never touched the manufacture of round or semicircular structures, it may seem that the process of their construction is quite complicated. In fact, with a phased analysis, it turns out that there is nothing difficult in building a concrete semicircular porch with your own hands.

The main thing is to properly plan, take care of the availability of all necessary materials and get an accurate view of all construction operations.

Basic operation table

construction operation Description
Planning, marking, calculation

At this stage, it is mainly determined how to make a semicircular concrete porch, what its parameters and dimensions will be.
Formwork creation

The formation of formwork for a concrete semicircular porch has its own characteristics. To get a perfect semicircle, you need to use materials that are strong, but malleable for bending.
Frame installation

A monolithic concrete porch must have reinforced frame. At this stage, its elements are prepared and fastened into a single structure.
Pouring concrete

Concrete is prepared by hand or made to order - depending on the conditions (porch volume, builder's abilities, financial capabilities).
Facing

The finishing of the concrete semicircular porch is carried out when the concrete is finally hardened. For decoration, outdoor moisture-resistant materials of increased strength are used.

Materials and tools

When building a semicircular concrete porch, it is necessary to stock necessary quantity materials and a set of tools:

  1. Formwork material, for example: galvanized sheets, cut into strips of large width.
  2. Reinforcement for the frame, thickness from 8 to 12 mm with a relief surface.
  3. Crushed stone and sand, if necessary - backfilling on the ground before pouring concrete.
  4. At self-manufacturing concrete will require sand, crushed stone and Portland cement, as well as a container and a mixing tool or a concrete mixer.
  5. Boards, bars for fixing the formwork.
  6. Finishing material, for example: paving slabs.
  7. Self-tapping screws, nails and other fasteners for fastening the formwork.

In order to positively solve the problem and get an answer to the question of how to make a round concrete porch, you may need other additional equipment applicable in a particular case.

Construction technology

When building a semicircular concrete porch with your own hands, it is very important to follow the sequence of steps and use only quality materials. It is especially important to correctly markup and layout.

Preparation, marking and calculation

Compared to a rectangular porch, a concrete semi-circular modification is more complex at the design stage. After all, you need not only to calculate the correct dimensions, but also the volume of concrete required and the width of the site.

For this, the following rules are used:

  • Determine the width of the site. Since it has a semicircular shape, the diameter is calculated instead of the width. In fact, at the wall itself, where the semicircle of the structure begins, the width will be equal to the diameter.

Its value must be at least 50 cm larger than the door itself. For example, if the door is 80 cm, then the diameter of the porch area will be 130 cm.

  • The middle axis of the porch. It should run exactly in the middle of the semicircle and coincide with the center of the door, although there are design options with the door shifting to one side or the other of the site, especially when the latter is quite spacious.
  • The size of the semicircles of the steps. Having calculated the diameter equal to the width of the platform, you can proceed to the calculation of each subsequent semicircle - steps.

The first step from the top should be 25-30 cm wider on each side of the platform diameter. For example, if the value of the last step is 130 cm, then the diameter of the 1st step from the top will be 190 cm. Accordingly, the 2nd step from the top will be already 250 cm, etc.