Answers to questions about OSB boards

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Oriented strand boards (oriented strand board) – a popular building and velvet material, developed in the United States specifically for frame housing. Today, OSB (OSB) is used not only in the construction of frame frames, but still raise questions, which will be answered by our website

1. What is the composition of oriented strand board?

The main material – wood chips – is immediately visible. This is the main feature of such slabs, they have a pronounced texture. Chips make up 90 to 95% OSB. The rest is synthetic resin binders containing formaldehyde.

OSB production

2. It turns out that OSB-boards are harmful, because they contain formaldehyde?

Yes, they can be used in interiors with some reservations. First of all, it is important to know that there are three classes of OSB according to the level of toxicity:

  • E0.5 – formaldehyde emission does not exceed 0.08 mg / m3 air.
  • E1 – the indicator does not exceed 0.124 mg / m3 air.
  • E2 – formaldehyde emission is 0.125 mg / m3 air.

Priming OSB boards

For premises, you need to choose the so-called ECO-plates of class 0.5. But they should not be left in their original form; subsequent finishing is required. Even if you want to leave the oriented strand board with its interesting texture, you should use at least a transparent special soil in two or three layers, which will protect the residents of the house from formaldehyde emissions, and the board itself from mold and mildew.

3. What thickness should the OSB be on the floor if laying on logs?

A minimum of 15 millimeters, but it is better to choose a plate 25 millimeters thick to ensure rigidity. Laminate or linoleum can be laid on OSB boards, as well as parquet and engineered board.

Laying OSB on the floor along the logs

4. What determines the moisture resistance of OSB boards?

In this case, you need to focus not on thickness, but on the type of plate, according to GOST 32567-2013:

  • OSB-1. The most fragile slabs, not resistant to moisture. Can only be used indoors in dry rooms and in the absence of serious stress.
  • OSB-2. Low moisture resistance, medium strength. Also only for dry rooms.
  • OSB-3. The most popular type of slabs. Can be used in wet rooms, strong, resistant, durable.
  • OSB-4. The most moisture resistant and durable type of slabs, however, it is not in demand among homeowners due to the too high cost.

Important! If OSB boards of the third type of moisture resistance are primed or painted with special compounds, then in their characteristics they will be compared with the boards of the fourth, most durable type.

5. What is the weakest point of the OSB?

Butt. It is through it that moisture most often gets into the material, which leads to the formation of mold, mildew, swelling of the plate. The end must be protected from moisture with sealants, all joints must be sealed without fail.

OSB floor sealing

6. What means can be used to increase the moisture resistance of OSB boards?

The ends are protected with special sealants, the front sides – with plasters, varnishes and paints. You should choose compositions that are not water-based, for the street – weather-resistant options.

OSB plaster

7. How long can the OSB remain without external finishing, protection?

Experts do not recommend leaving the slab without finishing and impregnation for more than two months. Especially when it comes to a cold season and a damp room. The sooner the OSB board is protected from external influences, moisture, the less the risk that the material will begin to peel and swell.

8. Frame house from OSB. How can you decorate such a facade?

Siding, just plaster and paint, use decorative panels for the facade or decorative stone. The choice is great. The main thing is that the stove does not remain on the street for a long time without finishing at all..

OSB facade cladding with decorative stone

Finishing the facade of an OSB house with decorative panels

9. Any outdoor paint can be used to paint the OSB facade.?

In theory, yes. But such a coating will deteriorate quickly enough. It is better to choose specialized paints that contain biocides against mold and mildew, as well as fire retardants, the use of which the portal wrote about. Remember that chips are the basis of the board, therefore, like wood, it must be protected from moisture and reduced flammability.

10. How to prepare an OSB board for painting and plastering?

Sand the surface, remove all dust and debris. Pre-treatment with a primer is required to increase adhesion, and in the case of plastering, a reinforcing mesh should be used. And, recall, you need to use compositions that indicate that they are suitable for oriented strand boards.

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