How To Prepare An Opening For An Interlevel Staircase

2023 Author: Douglas Hoggarth | [email protected]. Last modified: 2023-08-25 05:40

Determining the location of the stairs in the house
Ladder calculation
Determining the type of stairs
Installation of frame floor and selection of an opening in it
Heat and sound insulation of the floor
Opening cladding
Useful Tips

But for all the attractiveness of this occupation, the most difficult place is the device of an interlevel staircase. This article discusses the procedure for determining the place for a staircase, its type and obtaining an opening when reconstructing an attic in an old house.

Undoubtedly, the stairs made according to classical technologies with the use of expensive materials give the house monumentality, importance and special gloss. But modernity in the style of minimalism and a permanent crisis have led to the fact that nine out of ten homeowners of economy class will vote for the prudent use of space in their home and for saving money.

An interlevel staircase is an expensive structure. Especially if it is made to order. However, with some skill, you can do almost all the work yourself. This applies not only to calculations and construction of wooden, but also welded metal stairs. But before you start implementing your ideas in practice, you need to decide on the shape and location of the stairs, as well as prepare the opening.

Determining the location of the stairs in the house

Whatever it is, and everyone knows - the stairs take up too much space. The flatter it is and, accordingly, more convenient for passage, the greater the size of the opening under it and the further you need to move the first step away from the last in projection.

The most convenient staircase is one in which the width of the tread (horizontal part of the step) is at least 30 cm, and the height of the riser (the vertical part of the step) does not exceed 17 cm. Such indicators can be obtained if the angle of inclination of the staircase is within 30-40 degrees … Here are some simple rules, following which you can quite easily choose the location of the interlevel stairs in the house.

If possible, place the stairs in a non-residential area of the house. It is extremely inconvenient to use a living room if a bulky structure is installed in it.
If an interlevel staircase goes to the attic, then try to position it so that the exit is as close as possible to the longitudinal centerline of the attic.
Use a simple geometric rule to roughly estimate the length of the opening - a leg lying opposite an angle of 30 degrees is equal to half the hypotenuse. That is, with a ceiling height of 3 meters in the room and a staircase slope of 30 degrees, the opening length will be 6 meters.
The access to the stairs must be free. If something interferes with this, think about whether it is worth making the cross-country stairs.
There are types of stairs that practically do not take up space in the room, for example, spiral ones, but it is problematic to lift anything along them. Consider these projects as a last resort, with a preference for simpler models.
Ladders can be open and built. It is advisable to place open stairs where it is undesirable to clutter up the space with massive structures, and built-in ones where it is planned to use the space under the stairs (for example, for a guest bathroom or a pantry for household inventory).
Not in every place you can knock out an opening in the ceiling of the upper floor. If we are talking about a monolithic overlap or overlapping with reinforced concrete slabs, it is necessary to develop a separate project and endorse it with the author or in an organization recognized by the author of the entire house project.
If the size of the opening does not allow you to enter the staircase in the place that you determined as the best according to the above indicators, then you can reduce the opening by increasing the angle of inclination, but in this case, change the shape of the steps into a "duck step". Such a ladder is more difficult to manufacture, but it is very convenient at slope angles from 45 to 70 degrees.

Ladder calculation

Most ladders don't require grandiose mathematical calculations. It is important to be able to determine, using basic knowledge of geometry, the angle of inclination of the stairs, the number of steps, the height of the riser, the width of the tread and the length of the opening.

The initial data for these calculations is the height from the finished floor of the lower level to the finished floor of the second level. This means that if there are wooden floors on top of the concrete screed, then the height is measured from the concrete screed, since the wooden floors are not clean. The same rule applies to upper level floors.

For example, having measured the height of the slab at the place of installation of the stairs, the result was 3 meters. The most convenient angle of inclination of the stairs is 30 degrees, which means that the length of the opening will be 6 meters. With a tread width of 30 cm, 20 steps can be laid on the projection of the opening. Dividing 3 meters of floor height by 20, we get a minimum riser height of 15 cm.

However, most often such a long opening cannot be found even in a large house, but what can we say about a small one! Therefore, the next step will be to optimize the spatial arrangement of the staircase in the house while adjusting the size of the steps and risers, which is achieved by choosing the shape of the stairs.

Determining the type of stairs

In most cases, an internal inter-level staircase should provide a comfortable ascent and descent to a height of 2.5 to 3.2 meters. In this case, it is important that the opening takes up as little space as possible. And you can minimize the size of the opening by installing a ladder of a suitable type, which can be classified according to the following criteria:

According to the number of marches, one-, two- and three-flight stairs are distinguished;
By the presence of an intermediate platform, stairs with one and two intermediate platforms are distinguished. Straight and with a turn of 90 or 180 degrees;
According to the presence of winders, ladders with lower, upper, combined winders are distinguished, as well as spiral staircases, as an extreme case of using winders;
Ladders with straight steps and specially shaped steps, facilitating ascent and descent at slope angles of 45 degrees and more.

The choice of material from which the staircase will be made is also of great importance. After all, the assembly of a ladder on a single string made of wood is fraught with great technical difficulties. Such stairs are made of metal, which is much cheaper. In addition, under equal bearing capacity, wooden stairs will be much more massive than metal ones. Therefore, designers give preference to metal stairs when it is necessary to install an open staircase. But the choice of the material of the steps still most often remains with the type-setting - glued blockboard.

So, the choice of a two-flight staircase with one intermediate platform allows you to reduce the length of the opening by up to 30% and change the direction of movement along the stairs from 0 to 180 degrees.

The choice of a single-flight staircase with winder steps allows you to change the direction of movement along the stairs up to 180 degrees and reduce the size of the opening to 20%.

The choice of a spiral staircase allows you to reduce the size of the opening up to 80% and change the direction of movement up to 360 degrees.

Changing the slope angle of the stairs with a simultaneous change in the shape of the steps and combination with winder steps can reduce the size of the opening up to 60%.

Installation of frame floor and selection of an opening in it

Work on the construction of the stairs begins with punching an opening in the ceiling of the upper level. In this case, the material of the overlap is essential. If the floors are monolithic or made of slabs, then independent dismantling is impossible. This kind of work should be carried out by a company licensed for this type of activity. All work must be carried out in accordance with the agreed and approved project.

Self-dismantling is possible only if the upper level ceilings are wooden and do not bear a load. At the same time, it often happens that in old houses, attic floors are practically absent. This is most often due to the hasty post-war reconstruction of the house. In this case, it is best to remove the floors completely and replace them with new ones based on frame technology.

Photo 1. Fragment of the ceiling, restored using frame technology

Photo 1 shows a fragment of a remote attic floor, which was replaced by a frame one based on 50x120 mm bars, resting on the one side on the rafters through special support shoes (photo 2), and on the other side - on an I-beam steel that plays the role of a girder (in photo 3 the beam is shown from its bottom side). The support on the shoes allows you to significantly increase the maximum permissible load on the floor, since the risk of breakage of old rafter boards is significantly reduced, and the division of the floor by a beam in half allows you to dismantle the floor in parts.

Photo 2. Support shoe installed on the rafter

Photo 3. Support beam as a purlin

In photo 1, you can see that the opening for the stairs is highlighted in the cells of the frame. Here it should be borne in mind that the step of the rafters is 60 cm. And this size has not changed since these times. And the width of the stairs may vary. In this case, the width of the stairs along the steps is 65 cm, and the opening is 72 cm.

Photo 4. Embedded board for expanding the opening by an arbitrary size

The solution to this problem is shown in photo 4. As you can see in the photo, the frame beam is not supported on the shoe, but on the embedded board, which is installed between two adjacent shoes. Using this method, you can change the width of the opening by any amount up to the next beam.

Heat and sound insulation of the floor

After the frame is assembled, it must be sheathed from below with OSB sheets. For this purpose, a sheet with a thickness of 10 mm is quite suitable. When sheathing, it is not necessary that the edges of the sheets fall on the beams or cross members of the frame. After all, the final cladding will be made of drywall.

Photo 5. The overlap is sheathed from the bottom OSB

A fragment of the OSB sheathed from the bottom of the floor is shown in photo 5. After that, you can proceed to heat and sound insulation of the floor. It is best to use mineral or basalt wool as insulation because of their incombustibility. But before you start filling the cells of the frame with insulation, you need to lay out each of them with a vapor barrier. Photo 6 shows the cells of the floor frame, in which the film is laid and fixed with a stapler.

Photo 6. Laying vapor barrier on the bottom and walls of the cells

When all the cells are insulated, you can start laying the insulation. Its thickness should not be less than the thickness of the beams. In this case, 120 mm. Minvata can be laid denser with the expectation that it will settle a little later.

By the way, the same insulation scheme was used in the construction of the house back in 1940. Only instead of basalt wool, white glass wool was laid in the ceiling, carefully packed in bags of thick black paper. But over time, the glass wool stuck together and became completely flat, completely losing its insulating properties.

Photo 7. Cells after filling with mineral wool

Photo 7 shows the appearance of the cells after filling them with mineral wool. On top of the mineral wool you need to cover with another layer of film and secure it with brackets. This stage of work is shown in photo 8.

Photo 8. From above the mineral wool is covered with a film

And the last stage of work on heat and sound insulation is OSB sheathing of the ceiling from the attic side. When performing this work, in contrast to covering the ceiling of the ceiling, it is important to get on the edges of the frame with the edges of adjacent OSB sheets. Otherwise, at the joints, they will bend under the weight of a person. Photo 9 shows the appearance of the ceiling from the attic side after OSB installation.

Photo 9. Sheathing of the attic floor OSB

The thickness of the sheets depends on the pitch of the frame. So, with an average cell size of 40x40 cm, a sheet with a thickness of 15 mm is quite enough. If the size of the cells exceeds this value, then the thickness of the sheet must also be proportionally increased. The part of the opening that will be located above the back of the stairs can be reduced, but it is important not to forget to take into account the height of the person above average. This size is 190 cm. The opening should be reduced in order to reduce heat loss during heat exchange between levels.

The sides of the opening formed by the extreme floor beams must be flat. This is necessary because drywall will serve as the basis for finishing, which you can simply screw onto them with self-tapping screws.

Opening cladding

Facing the opening begins with the installation of a suspended plasterboard ceiling on the lower level. Otherwise, it will be impossible to calculate the size of the side slopes of the opening. Installation of a plasterboard ceiling is best done on metal profiles, rather than screwing drywall directly to the OSB floor. The fact is that when walking along the ceiling from above, in this case, the load will be transferred directly to the sheets, which will eventually wipe out on the heads of the screws. When drywall sheets are suspended on profiles, dynamic loads do not occur over the entire floor plane, but only at the points where the suspensions are attached to the ceiling. Such loads are quickly absorbed in ceiling structures without causing deformations. In addition, it is easy to hide all electrical wiring and other communications under such ceilings.

Photo 10. The plane of the ceiling next to the opening is sheathed with plasterboard

Photo 10 shows a working moment when the entire plane of the ceiling next to the opening is already hemmed with plasterboard along the profiles. The remainder, which includes the side ventilation pipe and the reduction of the opening along the back of the stairs, is sewn up last. In this case, you can take a sheet of drywall of a larger size, screw it into place, and then cut out the outline according to the footnotes made using the vertical level. These manipulations are shown in Photos 11-14.

Photo 11. Sheathing of a difficult part of the ceiling with a sheet of obviously larger size

Photo 12. Cutting along the contour marked by the level from the inside

Photo 13. Plasterboard exactly repeats the contour of the opening

Photo 14. Bottom view of the opening and plasterboard ceiling

After the outline of the opening is highlighted on the ceiling, you can fasten the side slopes. It is enough to fix them with self-tapping screws directly to the beams. The process is illustrated in photo 15.

Photo 15. Installation of side slopes of the opening

The edges must be reinforced with perforated aluminum corners. They are fixed with brackets using a stapler (photo 16). Then they are smeared with putty (photo 17) and then two more layers of putty are applied on the entire plane of the drywall with intermediate and final sanding (photo 18).

Photo 16. Installation of perforated corners on the edges

Photo 17. Putty of edges and seams

Photo 18. Fine putty

The opening prepared in this way is ready for most types of finishing, from painting to decorating with thin plasters, wallpaper or PVC panels.

Useful Tips

The use of facade putty will significantly expand the list of types of decorative finishing of the opening. After all, it is made on the basis of white cement and is much more reliable;
It is not necessary to revet the slopes of the opening with plasterboard at all if it is planned to cover it with clapboard;
After sanding, it is necessary to prime each layer of putty;
It is better to remove the wiring on the floor from OSB in non-combustible boxes.

The example of the opening used in the article as an illustration, and the technology of the work carried out are demonstrated by the example of the repair of an old German house built in 1940. The house was badly damaged during the war and post-war years. It was partially repaired by the household method, but no one has ever made major repairs in it. Therefore, the given example can be considered the most indicative and most difficult when arranging an opening for an interlevel staircase in a private house.

In the next article, devoted to the self-production and installation of an indoor staircase, we will talk about how to perform welding work using the example of a metal staircase with one bowstring, open steps and stringers.