Photo reportage: steps of outdoor insulation of a house

[owen]

Gentlemen,

I am amazed by your analyzes of my roof.

Thank you for all the info.

For yourself

[the middle]

A little feedback on my insulation (see beginning of the post)
The first winter after this insulation, comfort was significantly improved, except that the humidity in two rooms exploded (93% humidity)
It was panic.
Second winter, the humidity level completely stabilized at 61%!
(in the bedrooms)
And the temperature below has risen by two degrees compared to last year, in fact, we can put the wood stove at least, we always have + - 23 degrees in the living room, kitchen lounge ...
So, you have to wait 12 months for the walls to dry (in an old building like mine)
This humidity story was important, and I wanted to tell you :-)

[owen]

I followed your advice everything is back to normal.

I no longer have a humidity problem in my attic.

please

[Obamot]

Well, that's fun to hear!

Maybe you could tell us what exactly you did?

@ ++

[Edit]: I was also thinking about the sensitive point of the chimney flue (in red):

I return to the case of Owen, whom I salute.

[...] I summarize:
- detection of a non-stopped flow of hot air coming from lower floor / s / s.
- doubt about the function of the black membrane (condensation forming on a rain or vapor barrier?) And the construction of the roof.
- poor management of air circulation, due to a possibly incomplete diagnosis of the "causes".
- and finally condensation due to a defect in the design of the insulation (Owen himself detected an uninsulated area).

But ... I'm amazed that nobody has seen certain points. I give some tracks, without complete conviction, since I did not see the entire construction (so only based on the info in this thread and photos ...)

[1] 45 cm walls and age of construction
It is therefore a very old construction, therefore the main point raised by DD should be checked. Because to see the state of the roof inside, the Eternit cover is old, therefore asbestos => deadly poison to the four winds!

This type of old building was done at a time when there was no problem finding cheap fuel (usually wood heating, but not only). So we heated the rigot and the walls absorbed radiant heat which gave an impression of comfort with intense heat. Obviously once the heating reaches its optimal effect, the humidity vanishes, but returns when the heating is off. We all remember that we had to endure the cold in these houses: as long as the heating did not deploy all these effects. And in summer it was the opposite, these houses kept cool while outside prevailed the heat wave.

It should be remembered that some models of construction with thick walls, had been designed in medieval times, where according to various accounts, it was even hotter than in the current period.

[2] Attempt to rehabilitate / insulate old buildings => cold bridges
Obviously, the rehabilitation of construction not intended to be passive houses is not an easy task.
It would be necessary each time to proceed as Le_Juste_Milieu and start by making the insulation "from the outside", to bypass the problem of cold bridges and the accumulation of heat in the walls, with its inevitable correlation => condensation ...!

Whenever we apply modern insulation in this type of construction, we run into the worst difficulties, because obviously, having regard to the dew point, condensation does not necessarily appear at the place treated ... and for good reason! The whole construction is concerned. So we just put plasters on a wooden leg.

Despite this, we are going to start from the postulate, to isolate from the inside (solution that it would be better to avoid a priori ... because once the problem is solved in the attic, others may well appear in the rooms " to live"...). But you have to be pragmatic and deal with the case to be resolved.

I therefore propose an approach, which could eventually transform into exterior insulation later, since here we will only deal with roof insulation! And this, in order to make the current problem disappear.

[3] Identification of problems

Here is where potentially you are losing heat (in red):



So that we can see that the effort of having laid glass wool (in green) is reduced to nothing because it has not been laid where it should have been! So, what is needed is not so much to try to prevent the "cold from entering" (classic error of reasoning: it is not the cold air which enters but the heat which escapes ...) so rather to make sure that the heat cannot come out! It is then easier to identify what to do, and to set up the "right method" (or at least, the method adapted to each case ...).

The formation of condensation proves it: we can see that the loss was made largely and completely "next to" the glass wool insulation, which does not fulfill its role, but probably not in the right place!

As we can see, the possibilities for losing calories when the heat spreads outside are manifold:
- doors;
- Door step;
- seal around the door;
- floor (which someone saw fit to isolate as a priority);
- walls and along the walls ("stack" effect)
- various gaps ...
Indeed: "isolate" also means "confine" (notwithstanding the material itself, all the joints must be treated, nothing should filter more than what the substrate allows ... As an insulating substrate, you could also use cellulose wadding, which will be less harmful, but then you will need to apply a vapor barrier, since it is not integrated).

For the laying of glass wool, the protections of the skin, the eyes and the respiratory tract are imperatives.

So yes, of course. In severe cases it would also be better to insulate the door. But this is insufficient and we can see why.

[4] Possible solutions
It would be wise to put glass wool between the rafters (and against the walls, of course):



Choose the one that has a built-in vapor barrier (a kind of flexible cardstock, to put on the inside), and your problem will in principle be solved.

- then also against the other wall zones:



Continuation of the insulation of the walls in one piece, up to the roof ridge.

- preventing the cold air and the very cold from the outside from being in direct contact with the inside heat, is a sine qua non for neutralizing the cold bridges and de facto condensation, therefore to condemn all the entries of air and insulate the walls! I insist on the fact that in severe cases, it is necessary to put a plug of polyurethane foam in the air inlet itself and that it makes a covering on the internal wall, with edge-to-edge insulation. - edge (possibly with extruded polystyrene which blends perfectly with the polyurethane foam) => but not in the chimney flue where it is necessary to definitively condemn the air intake and insulate ALL the wall !!!
- seal all small airways with polyurethane foam;
- seal the door with a “d” seal (which traps an air cushion in its structure and which automatically adapts its shape to the interstices of the door frame). And put a threshold !!! (the seal must go all the way around without stopping, like the seal on a fridge door ...)

So you will benefit from double or even triple insulation:
1) the one placed between the rafters.
2) the entire volume of air contained in the attic, which will act as natural and free insulation.
3) the one on the ground, which has become useless but which, if you leave it, will further increase the effect and the feeling of comfort on the lower floors, since the air will be maintained there.

[denis]

from the moment when I see by vapor I see error, a hermetic house is a poison, then we ventilate, we invent the double flow etc ... that of the trade. Walls of 45 are surely in pizzé or in stone / lime, they must breathe be ventilated, so as not to collapse in the long run. . ; well I am in another logic (straw house, earth wood + mud), and each one its possibility; but the lost techniques are found, the materials free or almost and on the spot, just a little more time of patience .. ;

[Obamot]

Denis must confuse with the rain shield

He doesn't seem to know that the coefficients of permeability of vapor barriers vary according to the goal to be achieved ...

It is not chosen anyhow. He would do well to study the matter before his straw house rots from the inside, he who so loves to give lessons.

[denis]

Denis must confuse with the rain shield

He doesn't seem to know that the coefficients of permeability of vapor barriers vary according to the goal to be achieved ...

It is not chosen anyhow. He would do well to study the matter before his straw house rots from the inside, he who so loves to give lessons.

I give lessons? . ... .


Vapor
definition: vapor barrier
A vapor barrier is a material that prevents the passage of water vapor. It prevents condensation of water vapor inside the wall and in particular in the insulation. To meet this goal, it must have a high resistance value to the diffusion of water vapor. it generally consists of a sheet which is waterproof against water vapor and is placed on the warm side internally with the insulation.

it's stupid, when I read by steam, I understand by steam, not, by rain !! lol

lesson giver? I am not to post at any time, without trying or creating things for advanced. If I have sometimes hurt it is only by mistake, I am a little provocative? here. I do not know your achievements, I have not seen! lol. And swing theories and numbers for, and then I don't care, I don't have that to do, hi
end of the story

[Obamot]

... apparently Denis doesn't seem to understand the blah-blah he posts himself:

definition: vapor barrier
A vapor barrier is a material that prevents the passage of water vapor. It prevents condensation of water vapor inside the wall and in particular in the insulation. To meet this goal, he must present a value of resistance high to the diffusion water vapor.

And yes ... I didn't say anything else. And besides this definition is false or incomplete for its continuation:

it usually consists of a leaf watertight with steam and place it on the warm side internally with insulation.

Because indeed, a vapor retarder (more appropriate term) cannot at the same time be "tight" and have a "high resistance" (either the layer is hermetic - and the resistance is total - or it is not. ... and then the steam cannot .... diffuse CQFD. Besides, what a disaster it would be, a seal ...)

The rest (I mean ormis aggressiveness and big blah-blah) = rotting of wire. Because Owen told us that he is delighted with the disappearance of his condensation problem. What else?
In short, Denis like himself, a great fan of blah blah, except that when asked a question a little more in depth, there tagada, there is no one left, among the Dalton's:
https://www.econologie.com/forums/post238614.html#238614
https://www.econologie.com/forums/post237964.html#237964