OSB sheet size: standard parameters, classification

OSB or OSB slabs are a building material with a unique set of properties that have created for it a wide range of applications in construction and repair. Today we will tell you in detail about the material itself, find out the standard size of the OSB sheet, and also see how it can be used on the facade of your house under construction or finished.

Classification of OSB boards

If you decipher the abbreviation OSB, then we get rough particle boards. What does this name mean? The material is a multi-layer board obtained by pressing wood chips of a certain size under high pressure, mixed with an adhesive mass. This symbiosis gives the material its basic properties.

Depending on the type of raw material, OSB sheets can be different, so when choosing the best solution for specific tasks, it is worth considering many factors, which we will now talk about in detail.

So, let's just say that in the manufacture of OSB manufacturers can focus on different standards: USA , The European Union and Russia.

Interesting to know! Russian companies are guided precisely by international quality requirements, since our GOST R 56309-2014 was developed on the basis of the European standard EN300: 2006, as evidenced by even the same labeling of products released separately according to both standards.

Therefore, let's take a look at the requirements of the EU and US standards in order.

EU Normative Documents

The main quality criteria for OSB boards in Europe are reflected in two normative documents: EN300 and EN13986.

The first text is more common, so we will take it as the basis of our story. It defines the following fundamental characteristics of the material:

Resistance of the front surface to abrasion.
Flexural strength.
Interaction with various coatings.
Holding the fasteners.
Resistant to wet environments.
Spatial strength.
Fire resistance.

According to the specified characteristics, all OSB boards are divided into 4 quality classes:

OSB 1 - panels intended for use in dry rooms and the construction of light, unloaded structures.
OSB 2 - these panels are also used in dry environments, but they are already able to withstand loads in various structures.
OSB 3 - these sheets are considered universal, as they are able to withstand loads and at the same time be used in wet conditions.
OSB 4 - the highest quality material intended for high-load structures. It is absolutely not afraid of water and perfectly resists open flames.

What is meant by dry and humid environments? In the first case, we are talking about air with a relative humidity of no more than 65% percent (this threshold can be exceeded several times a year for a period of no more than a week) at a temperature of +20 degrees Celsius. Humid air at the same temperature can exceed 85% humidity.

US and Canadian standards

What is the difference between the US requirements? On the shelves of domestic stores, you can find products from North American companies. These sheets will have different markings from European ones, which must be remembered in order not to make a mistake in choosing for specific purposes.

These countries also have two standards: CSA0325 and PS2. Interestingly, many companies adhere to both standards at once, since in terms of resistance to loads, the degree of swelling of the material and some other parameters, they coincide. It is worth remembering that these panels are not categorized.

Here, a certain marking of the sheets is used, indicating certain properties. In the OBS marking, the following designations can be found:

W - such slabs are intended only for facing vertical surfaces, that is, walls.
1F - This material is used as flooring.
2F - they are also used as a floor covering, but they can only be laid on a flat rigid base, while the previous version can also be mounted on logs.
1R - intended for a continuous roof sheathing, without creating support at the edges.
2R - also used for lathing, but with support along the edges.

Let's explain in more detail. Each indicated marking can be found on several types of OSB at once. In this case, each value will be accompanied by an additional digit in inches, which will indicate the maximum permissible distance between the chords of the frame on which the slab will be mounted.

The next important mark in the marking will indicate the degree of humidity in which the panels will be used.

There can be three options:

Interior - it's not hard to guess that such material can only be used indoors, in comfortable conditions. Moisture is destructive for him.
Espоsure type bindеr - these structural types are able to withstand moisture, therefore they can be used both for indoor and outdoor work, but only after preliminary treatment with protective compounds.
Exteriоr bond - such boards can repeatedly withstand the processes of wetting and drying, without changing their main characteristics, without swelling. They can, without suffering, contact the ground, or be in the pouring rain.

You can draw parallels between the US and EU markings and find similar materials, however, products from North America really have the best assortment and the ability to choose an option for specific needs.

Interesting to know! Wood for the manufacture of OSB is used in different ways. So, if in America poplar mainly goes there, then in Europe conifers are most often used.

Prices for OSB (oriented strand board)

~~OSB (oriented strand board)~~

Video - Overview of OSB boards

Difference of OSB sheets by edge and type of surface

Material specifications are important in first of all, but not only they determine the type of material. It is also important to know what is the external difference between the panels, which will come in handy when creating a building design and installation.

What other OSB sheets are there?

1. The simplest and most inexpensive will be sheets with an untreated rough surface that are machined. The material has good adhesion to bituminous materials. They use it as a base for roofing decks as a continuous sheathing.

The surface of these sheets will be smooth, so paint will adhere well to them.

3. Lacquered boards are covered with pasty lacquer on the front side. This treatment provides additional protection against moisture and gives the surface more aesthetics. The varnish is applied by roller machines.

The surface of the slab is pre-primed, which reduces the consumption of varnish and allows, if necessary, to pigment the surface areas to achieve the desired appearance.

4. The last type is called laminated. A continuous polymer layer of protection is applied to the surface of the board. This technology makes it possible to obtain a material with a surface of different colors.

The edge of OSB sheet can be of two types - straight or curly. The first option is used as a rough material for finishing, as well as for the production of containers, while the second can be used as a finishing lining.

The curly edge means the presence of grooves and edges on different sides of the panel, due to which you can collect solid planes with high-quality joining of the material. Thanks to this connection, it is possible to achieve better thermal insulation (the material is not blown through) and sound insulation.

What sizes are OSB boards?

The standard European size for OSB panels is practically the same as for drywall sheets - 1250 * 2500 mm.

In square meters, the area of the sheet will be three. That is, the material is large enough, which allows you to sheathe large spaces with it, spending a minimum of effort.

US size is slightly different - 1220 * 2440 mm. As you can see, in both cases the sides are multiples of each other, which is done for more convenience in constructing the frame. Why the same principle is not taken as a basis for the production of drywall remains unclear.

If you require non-standard solutions, you can look for panels with a longer length. This can be 3000 and 3150 mm. Material up to 7 meters long can be purchased on request. These are mainly used for the facades of tall buildings.

However, they often think not about choosing the length when buying a material, but about its thickness, which will vary depending on the class and purpose of the panel, as well as on the distance between the chords of the frame.

Selectable thickness from 6 to 25 mm , like plywood.

Its weight will directly depend on the thickness of the sheet. This indicator is also influenced by the density of the material.

Interesting to know! Some sheets of standard sizes can weigh up to 100 kg.

Renovation of the facade of the OSB building with panels

OSB boards, as we already understood, can be used in different ways, depending on a number of factors.

Of these, they even manage to build full-fledged warm houses - here the material acts as a base for expanded polystyrene. The symbiosis of these materials allows you to create special sandwich panels, as in the photo below.

The building is assembled from such sandwiches like a constructor. A very interesting technology, but today we will not talk about it, but about the use of separate OSB sheets to decorate the existing facade. Let's see how you can transform your home, and what additional benefits you can get from it.

So, let's imagine that we have in front of us the facade of an old house that we want to update. OSB is sewn onto the frame, which means that the structure can be additionally insulated, and it would be simply stupid not to take advantage of this opportunity.

Table 1. Installation of OSB panels.

Steps, photo	Description
Step 1 - make the crate	The frame for the sheathing will consist of several layers - crate and counter battens. This will allow you to install insulation, provide space for ventilation, or add a second layer of insulator and make the structure more durable and reliable. The photo shows the structure of the lathing with insulation. We see vertical racks made of timber, between which sheets of mineral wool are installed. In this manner, we will have to equip the entire facade without gaps.
Step 2 - determine how to attach the belts	If the walls of the house initially even, then the task before you is not the most difficult - the racks can be installed directly on the surface without additional alignment. However, this is extremely rare, so let's not hope for the best and describe the alignment technology. Note! Let's say right away that the base for the cladding, which is the frame, must be perfectly flat so that there is no internal stress in the panels, so do not be lazy to level the walls, if required.
Step 3 - main verticals and horizontals	When determining the parameters of the frame, you must, first of all, be guided by the dimensions of the purchased OSB sheets. We know the standard, so the distance between the posts needs to be 62.5 cm. This will allow the panels to be mounted in any position. 1. So, the first step is to install the corner posts. We set them exactly vertically using a laser or bubble level. 2. A wooden bar with a cross section of at least 50 * 50 mm is used as racks. 3. A nylon thread is pulled between the extreme uprights from above and below. We need this element to set the remaining racks in one plane. 4. Next, mark the spacing between the posts according to the step above. 5. Take a bar and check if it can be installed everywhere so that the thread does not change its position. If there is not enough space, the outer racks should be moved away from the wall to the required distance. Do this evenly, otherwise you will get uneven slopes on windows and doors. 6. You can move the timber away from the base using metal hangers or corners, as in the presented photo. 7. Then the main vertical and horizontal lines are placed, the position of which is determined by the already stretched thread. We are talking about the elements that form the slopes of door and window openings. After assembling the battens, the space between the belts is filled with sheets of mineral wool or foam. One more thing. If a counter-lattice is planned for installation, then the step between the belts can be reduced so that the insulation does not need to be cut.
Step 4 - counter-lattice and insulation with the second layer	Installing the counter lattice will not be difficult, since we have already brought the first part of the frame to the level. Your current task is to break the distance into steps of the desired size, screw the beams perpendicular to the previous ones on wood screws, install insulation, blocking the cold bridges of the first layer, if required. Tip! It is very important if OSB without a profile edge is used, to install jumpers at the locations of the seams, otherwise the sheathing will be mobile and may bend in different directions, which will ruin the finish.
Step 5 - installation of waterproofing	Mineral wool is very afraid of getting wet, so it needs to be covered with a special waterproofing film. It is fastened with a stapler on staples. Next, another level of the counter-lattice is made. This space will already be used for ventilation of the insulation, for its high-quality drying. The fastening principle is exactly the same as before.
Step 6 - OSB sheathing with plates	Next, the OSB frame is sheathed panels. They are installed so that the edges fall exactly in the middle of the belts. Fastening is carried out with self-tapping screws for wood of the appropriate length (it is required that the fasteners enter the timber by at least 2 cm). It will be very good if one sheet covers the entire height of the wall to avoid unnecessary transverse seams. OSB is attached to all belts that pass under it. Cutting material is best at the corners of the building. This must be done with a circular saw with a medium tooth. You only need to cut along the guide so that the edges are smooth and beautiful.
Step 7 - jointing	Now the coating is needed protect and decorate. We start by sealing all the seams. For this, a special elastic putty is used, for example, "Holzer Flex Spachtel Elastish". The seams are embroidered 5-7 cm in each direction from the seam, the layer of putty is 3 mm. It will dry out within 10 hours. Look for information on similar materials on their packaging.
Step 8 - painting	Further, the entire surface of the sheets together with putty covered with a special primer paint for OSB. This material can be tinted in any color, it will add not only attractiveness, but also qualitatively protect the skin from moisture. The coating lasts 10 years, after which it will need to be reworked. Which paint is suitable for OSB panels? Read more in a dedicated article.
Step 8 - Installing decorative strips	Seams are closed decorative panels - so you can create an imitation of the German style of building a house - half-timbered. The panels are glued or on galvanized self-tapping screws.