I have tried to understand the problem with single-sealed facades.
The problem is said to be that there is no air gap in the wall between the facade and organic material in the wall, as I understand it.
But if we look at older plastered wooden houses then.
The plastered houses I have looked at a bit more closely (not that many), they have a wall of either solid wood, standing tongue and groove 60mm thick planks. Or a "normal" stud wall with either raw tongue and groove boards or a sheet material (I have seen houses with asfaboard).
On this, a layer of plaster is applied directly, completely without an air gap. The plaster usually has a layer of reed mat on the inside as some sort of reinforcement, and also chicken wire or real plaster mesh as reinforcement. It is possible that a wind protection paper is also laid against the wood then. I have never heard that plastering would cause moisture problems.
Is it possible that this layer of reed provides a narrow air gap?
As I understand it, the difference between an old plastered house and modern problem houses is that today there is a polystyrene board on the outermost layer of the wall construction, and then plaster is applied directly to it, I assume plaster mesh is used to reinforce it.
IF it were that the polystyrene is too dense, so that moisture stays between the polystyrene and the plaster, then I can imagine that it can cause problems for the plaster itself, which does not dry out properly. But then it is not moisture against organic material. As I understand the problem, it causes moisture damage to the studs in the wall? The moisture that reaches the studs should cause as much/little problem in plastered houses as in single-sealed modern houses, right? And shouldn't the wall "breathe out" through the plaster, which is not vapor proof, or is the polystyrene there with certain vapor-proof properties?
The problem is said to be that there is no air gap in the wall between the facade and organic material in the wall, as I understand it.
But if we look at older plastered wooden houses then.
The plastered houses I have looked at a bit more closely (not that many), they have a wall of either solid wood, standing tongue and groove 60mm thick planks. Or a "normal" stud wall with either raw tongue and groove boards or a sheet material (I have seen houses with asfaboard).
On this, a layer of plaster is applied directly, completely without an air gap. The plaster usually has a layer of reed mat on the inside as some sort of reinforcement, and also chicken wire or real plaster mesh as reinforcement. It is possible that a wind protection paper is also laid against the wood then. I have never heard that plastering would cause moisture problems.
Is it possible that this layer of reed provides a narrow air gap?
As I understand it, the difference between an old plastered house and modern problem houses is that today there is a polystyrene board on the outermost layer of the wall construction, and then plaster is applied directly to it, I assume plaster mesh is used to reinforce it.
IF it were that the polystyrene is too dense, so that moisture stays between the polystyrene and the plaster, then I can imagine that it can cause problems for the plaster itself, which does not dry out properly. But then it is not moisture against organic material. As I understand the problem, it causes moisture damage to the studs in the wall? The moisture that reaches the studs should cause as much/little problem in plastered houses as in single-sealed modern houses, right? And shouldn't the wall "breathe out" through the plaster, which is not vapor proof, or is the polystyrene there with certain vapor-proof properties?
In short, the problem with single-layer sealed stucco facades is that water that penetrates cannot escape. The styrofoam is too dense. Single-layer sealed facades worked only in theory. It was assumed that water would not penetrate. But it turns out that almost no builder has managed to construct a house so tightly sealed that moisture does not penetrate. Weak points include windows, but even something as simple as drilling a hole to attach downspouts. And which homeowner realized the risk of retroactively installing a facade lamp, a climbing trellis for the roses, etc.?
One thing I've been thinking about is all those poor people who have to renovate their facades. It's actually not that simple to just tear off the Styrofoam and replace it with a ventilated facade. The Styrofoam was often 70 mm and had significant insulation capacity.
But if the moisture thus gets trapped between plaster and Styrofoam? It doesn't do any significant damage there, does it? Or is it that it also penetrates past the Styrofoam, reaching the wooden structure?
I have seen houses where a steullsskiva has been mounted on the wall as an addition and then plastered directly on it, does that mean that type of house is not affected? I was thinking, if it's really dense Styrofoam that's the problem?
I have seen houses where a steullsskiva has been mounted on the wall as an addition and then plastered directly on it, does that mean that type of house is not affected? I was thinking, if it's really dense Styrofoam that's the problem?
The frigolite is not dense and in one piece across the entire wall. And behind the frigolite, there is wood.
That it worked on old houses is not so strange. The same answer as usual - poor insulation meant that the wall was warmer further out in the construction, and this keeps the moisture away.
That it worked on old houses is not so strange. The same answer as usual - poor insulation meant that the wall was warmer further out in the construction, and this keeps the moisture away.
Then there are the purely practical problems with plaster on polystyrene: There is nothing to attach, for example awnings and fixtures. Playing football by/against the walls is prohibited, not to mention the delicate maneuver of cutting the grass next to it. A colleague had to repair the facade after snowball throwing. Another colleague found their parasol deeply embedded in the wall after a storm...
Administrator
· Skåne
· 8 624 posts
I think Lotta Fredriksson described it well in this article, back in 2007 when it was revealed: https://www.byggahus.se/bygga/nya-hus-ruttnar-mglar
Foam plastic should only be used on stone matrl.......
I assume you mean the part about people making mistakes, and then I wonder; what world do you live in?stake said:
If you read the other posts as well, you can see that it doesn't even require mistakes. It's enough for someone to install a lamp, an autumn storm to throw something against a wall, or the kids to "park" the bike a bit carelessly against the wall for damage to occur. The system is therefore not suited for normal use of a residence.
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You assume wrong.ToRy said:
I know that people make mistakes, saying that it's a useless system that can't be operated because no one is capable of doing it without mistakes is nonsense.
If you also try to install a satellite dish or an awning, you have only yourself to blame, it's not the system's fault but the idiot who tries to mount a heavy metal plate onto something with the consistency of a marshmallow.
Smart alek
· Västra Götalands
· 11 116 posts
"Nobody" certainly brings out the mathematician, but we can leave it at that. Evidently, it has not been done correctly. If more than 50% (the figure mentioned above) suffer from moisture damage, then the industry is either unable to perform it correctly, or people cannot use it correctly. The system is therefore a "Murphy" in professional terms. And because it is, it is bad and should/shall not be used. There is no such thing as "technically perfect in isolation." Everything is part of a system, and one must include those who are to execute and use it, considering their experiences, knowledge, resources, economic motives, and other conditions they have.stake said:
And a system that doesn't allow you to mount anything on the facade is not usable. It is such a significant deviation from what one can expect from a house that they should have been *very* clear about it from the sellers.
Personally, I have no direct stake in this, other than we visited a large area that was constructed in this manner. And they promised golden prospects and that there would certainly be no problems (the fact that you couldn't put up awnings was not mentioned at all). Now, I didn't believe in the method; since it was new, the only reasonable reason for its introduction was that the builders could make money from it. And saved money often results in poorer quality for the customer (if no technological shift has occurred, which I couldn't see here). So it was left alone. I'm quite glad about that today.