Polish wall/ceiling construction, OSB far out?

[Prosit]

I am considering hiring a Polish house builder to construct my new house, but I have some questions about the company's standard wall.

The wall is not that unusual except that they put OSB on the outside of the studs and then another layer of insulation. The roof also has OSB instead of board sheathing like we usually have here at home.

Details at:
http://www.firmakubus.pl/se/teknisk-information

What do you think? Are there any problems with their constructions?

(I will want the walls "my way," but I don't yet know how flexible the company is.)

 

[KnockOnWood]

Hello Prosit, you have probably heard about the problems with plastered walls without an air gap.

Called single-step sealed facades. This seems to be something similar, so watch out!

http://www.google.se/#hl=sv&source=....3&bav=on.2,or.r_gc.r_pw.&fp=11f5eab39e799eba

 

[Prosit]

In our case, it will be wood siding, and of course, we will ensure there is a ventilation gap there as well.

What I'm really wondering about is the use of OSB on the exterior in the wall construction - let's say it's immediately inside the ventilation gap, is that a good climate for OSB or will it become damp?

The roof is also a question mark - it might feel best with raw planking, but what about plywood or OSB instead?

Here are some pictures: http://www.firmakubus.pl/se/images/Naset/flashThum/index.html

 

[pickels]

OSB that gets damp tends to swell and separate, surely the strength deteriorates but that's just my two cents.

 

[Fredrik.engdahl]

many houses in the USA also use OSB as weather protection instead of exterior gypsum. seems to work if you cover it quickly enough against precipitation.

Roof plywood is sometimes used on roofs in Sweden.

it takes a while for OSB to absorb moisture if it is not soaking in water

 

[zsimpey]

Well, what can you say, OSB sucks?

 

[Prosit]

When it comes to the walls, it is common in Sweden to have just wind paper (or equivalent) on the outside and not sheet material? I'm talking about wooden facades, that is.

 

[Enk Projektet]

Don't they use OSB to make it torsionally rigid?
Not an unusual or new solution.... there are many 70s-80s houses with 8mm plyfa on the frame and then facade brick.
I myself use wind barrier...

 

[isolde]

I am a bit surprised when I realize that many people seem not to be aware of the different classes of OSB boards. There are at least 4 classes of OSB boards, which differ in terms of strength and durability in humid environments. There are also fire-rated OSB boards (Euroclass B, equivalent to painted gypsum board). However, which type of OSB boards the thread creator's intended supplier uses, I leave unsaid.

 

[pickels]

I am a little surprised when I realize that many seem not to know about the different classes of OSB boards. There are at least 4 classes of OSB boards, which differ in terms of strength and durability in moist environments. There are also fire-rated OSB boards (Euroclass B, equivalent to painted gypsum board). However, I will not speculate on which type of OSB boards the thread creator's intended supplier uses.

You see, you learn something new every day..

 

[Ohver]

Hi, I extended a bit with a guy from Latvia. The house has a wooden facade and instead of wind barrier he used OSB. I read somewhere in building codes that a rule of thumb is that the inside should be five times tighter than the wind indicator. Has anyone heard or seen differently?

 

[Pumabjörnen]

OSB is a great material, provided that, as Isolde mentioned above, it is the right type of OSB for the intended use.

Unfortunately, there is a general perception among craftsmen that OSB is an inferior material compared to plywood, but anyone who does a little quick research on the web quickly realizes that it is not just glued leftover chips.

The interior climate shield should indeed be at least 5 times tighter than the exterior.

 

[Ohver]

OSB is a great material provided that, as isolde mentioned above, it's the right type of OSB for what you intend to use it for.

Unfortunately, among craftsmen, there is a general view of OSB as an inferior material compared to plywood, but those who do a little light research on the web quickly realize that it is not just glued-together leftover chips.

The interior climate shield should indeed be at least 5 times tighter than the exterior.

The OSB that is on the outside is standard from Jem&fix, so it's probably not great to have it where it is. But then the question becomes, has he done it right or wrong!?

OSB is a great material provided that, as isolde mentioned above, it's the right type of OSB for what you intend to use it for.

Unfortunately, among craftsmen, there is a general view of OSB as an inferior material compared to plywood, but those who do a little light research on the web quickly realize that it is not just glued-together leftover chips.

The interior climate shield should indeed be at least 5 times tighter than the exterior.

 

[Pumabjörnen]

The OSB that is on the outside is standard from Jem&fix, so it might not be the best to have it where it is. But the question remains, has he done it right or wrong!?

As far as I know, there is no prohibition against using plywood or OSB, but my understanding is that from a Swedish building code perspective, you usually want an inorganic capillary-breaking outer layer like a weather barrier/cement-based boards or exterior gypsum. I've also seen that additional insulation is installed without a barrier when using boards with high wind resistance (this, however, requires high precision in installation) to counteract wind and moisture transport into the wall.

However, I do feel that OSB with its waxed surface might absorb less moisture initially than plywood if exposed.

Since you have an outer panel and hopefully an air gap before the mentioned OSB, I don't think there is a major risk, but if it were to be exposed to large amounts of moisture/water, such as in a type of leak, it will likely react to it relatively quickly as it is not intended to withstand it.

Right or wrong is not for me to decide, didn't you have an inspector or controller come out? If they thought it was okay, I would assume it's acceptable.

I would advise you to take good care of your facade, no bushes or climbing plants next to the house there, and I would not think there is any danger.

Craftsmen from other countries often do, in my experience, what they're accustomed to in their homelands (probably according to their building codes) and as the client, it's, in my opinion, up to you to ensure the work is done correctly (or alternatively pay and entrust it to a professional).

I'll summarize it as vaguely as possible by saying he might have unknowingly done it wrong.

 

[Ohver]

Thank you for the answer! Yes, the exterior is sealed; there is nothing close to the facade. It is vertical paneling, so there should be good air circulation.