Hello,
My wife's family (Poles) is helping us renovate our new old house. It more or less requires a total renovation. I have a wall question...
The exterior wall is double-layer brick. The previous owner had a fiberboard + masonite on the inside. It is quite moisture-damaged today.
After tearing down the fiberboard, we find a rather even and nice "cement surface." The Poles are happy about this and say it will be perfect to spackle directly on the cement.
My question to those who know: Can you do that? Spontaneously, I feel that a moisture barrier is missing here, or am I wrong?
I should perhaps add that we will later insulate the house externally. Probably with 10 cm of XPS and plaster on that.
Grateful for quick and good answers... I don't know how long I can hold them off before they start with plaster and spackle...
/Kristian
My wife's family (Poles) is helping us renovate our new old house. It more or less requires a total renovation. I have a wall question...
The exterior wall is double-layer brick. The previous owner had a fiberboard + masonite on the inside. It is quite moisture-damaged today.
After tearing down the fiberboard, we find a rather even and nice "cement surface." The Poles are happy about this and say it will be perfect to spackle directly on the cement.
My question to those who know: Can you do that? Spontaneously, I feel that a moisture barrier is missing here, or am I wrong?
I should perhaps add that we will later insulate the house externally. Probably with 10 cm of XPS and plaster on that.
Grateful for quick and good answers... I don't know how long I can hold them off before they start with plaster and spackle...
/Kristian
Relatives are right. Trust relatives who don't know much about wooden houses but generally know almost everything about a stone house . Forget everything about plastic and moisture barriers in the walls if you have a proper brick house.
Plaster sold under the name GYPSUM (if I remember correctly) will be perfect on your interior walls, I think. Gypsum plaster is also used in Poland to achieve a smooth finish indoors, so your helpers should recognize this material .
Good with external insulation.
Good luck!
gaia
. Forget everything about plastic and moisture barriers in the walls if you have a proper brick house. Plaster sold under the name GYPSUM (if I remember correctly) will be perfect on your interior walls, I think
. Gypsum plaster is also used in Poland to achieve a smooth finish indoors, so your helpers should recognize this material . Good with external insulation
.Good luck!
gaia
Member
· Västra Götaland
· 545 posts
Don't destroy the house with celloplast and thin plaster!!! > > >
Mineral wool and thick plaster - but the Poles can't (someone needs to explain)
> >Mineral wool and thick plaster - but the Poles can't (someone needs to explain)
LyckeK do you have diff data for EPS adhesive, respectively facade-EPS, respectively plaster?
And do you have corresponding data for mineral wool and plaster?
Brick is quite diff slow on its own. The surface against the insulation becomes quite warm in this case and can drive out quite a bit of moisture, on the other hand, brick absorbs a lot of moisture. Ideally, one would encapsulate the house and use dehumidifiers before insulating.
Is it really EPS+adhesive that is the risk of damage with the "normal" use of those systems?
Isn't it more that moisture is trapped "cold" in the wall when insulating from both sides, and do you solve that problem with mineral wool?
And do you have corresponding data for mineral wool and plaster?
Brick is quite diff slow on its own. The surface against the insulation becomes quite warm in this case and can drive out quite a bit of moisture, on the other hand, brick absorbs a lot of moisture. Ideally, one would encapsulate the house and use dehumidifiers before insulating.
Is it really EPS+adhesive that is the risk of damage with the "normal" use of those systems?
Isn't it more that moisture is trapped "cold" in the wall when insulating from both sides, and do you solve that problem with mineral wool?
Member
· Västra Götaland
· 545 posts
oh dear... ;D
no, I don't have them in my head - and I don't feel like chasing them either...
But - here we have a house with a massive brick structure! - why should we introduce a system that doesn't automatically integrate with the existing one.
Without any data to support it, I don't think we need to question that a cellplast is MORE diffusion-tight than a mineral wool and that a KC-bruk is more diffusion-open than a mortar based on acrylic or water-repellent KC-bruk
If the brick can be considered warm, it will be able to push moisture a bit into the cellplast but there it will soon meet the cold and thus condense... it doesn't matter as long as it happens in the insulation.
BUT if condensation occurs on the surface of the cellplast, there will be a lot of water running down and into the construction - on the mineral wool there is no surface to condense on and any condensation water runs through the insulation and downwards - onto a metal sheet and out...
If we trap moisture in a wall with mineral wool, we do not prevent it from escaping - even if it takes longer than if the wall was uninsulated
no, I don't have them in my head - and I don't feel like chasing them either...
But - here we have a house with a massive brick structure! - why should we introduce a system that doesn't automatically integrate with the existing one.
Without any data to support it, I don't think we need to question that a cellplast is MORE diffusion-tight than a mineral wool and that a KC-bruk is more diffusion-open than a mortar based on acrylic or water-repellent KC-bruk
If the brick can be considered warm, it will be able to push moisture a bit into the cellplast but there it will soon meet the cold and thus condense... it doesn't matter as long as it happens in the insulation.
BUT if condensation occurs on the surface of the cellplast, there will be a lot of water running down and into the construction - on the mineral wool there is no surface to condense on and any condensation water runs through the insulation and downwards - onto a metal sheet and out...
If we trap moisture in a wall with mineral wool, we do not prevent it from escaping - even if it takes longer than if the wall was uninsulated
Thanks for the tips.
"tjockputs" how thick is it usually and how thick mineral wool is suitable?
"varmt tegel" how do I know if I have it or not?
We will, in any case, postpone the insulation until spring or summer. I think it has gotten a bit wet outside and I'm focusing on renovating inside instead now. I'll have a little more time to convince the Poles about which plastering system is best then too... If I know myself...
:-/
"tjockputs" how thick is it usually and how thick mineral wool is suitable?
"varmt tegel" how do I know if I have it or not?
We will, in any case, postpone the insulation until spring or summer. I think it has gotten a bit wet outside and I'm focusing on renovating inside instead now. I'll have a little more time to convince the Poles about which plastering system is best then too... If I know myself...
:-/
Member
· Västra Götaland
· 545 posts
check out other posts from me on this forum and you'll get many arguments... :
The plaster will be about 20mm and the insulation can be 50-100mm (or more, but 100 is probably enough - the walls will still be thick)
The plaster will be about 20mm and the insulation can be 50-100mm (or more, but 100 is probably enough - the walls will still be thick)
Since I usually play the devil's advocate, or the contrary old lady. Your choice. I can't help but question a bit more.
LyckeK wrote:
Next question is purely about moisture dynamics. Does the risk really exist in practice if you calculate with reasonable insulation thicknesses, reasonable indoor humidities, and the existing outdoor climate? (And no, you don't need to sit and solve partial differential equations for me. ) The question of moisture in the wall due to rain, etc., before we mount it, we disregard in this case. That is a question for the supplier to define safe intervals/methods.
Then for the sake of clarity, as long as a material is reasonably diffusion-open, we are not trapping moisture.
Which leads to what I mentioned in the previous post, but let's skip the numbers. Is EPS+thin so tight that it approaches the brick's diffusion values, which means that EPS+thin is no more than 10 to 20 times more open?
KristianH wrote:
Otherwise, you take as thick insulation as you can. It is essentially the thickness of the insulation that determines your wall's U-value.
I can't help but question a bit more.LyckeK wrote:
Do we really have such a good handle on where the water runs in the mineral wool? It has a bunch of fibers to run along, and are we truly guaranteed that it doesn't follow fibers inwards towards the underlying wall?
Next question is purely about moisture dynamics. Does the risk really exist in practice if you calculate with reasonable insulation thicknesses, reasonable indoor humidities, and the existing outdoor climate? (And no, you don't need to sit and solve partial differential equations for me.
) The question of moisture in the wall due to rain, etc., before we mount it, we disregard in this case. That is a question for the supplier to define safe intervals/methods.Then for the sake of clarity, as long as a material is reasonably diffusion-open, we are not trapping moisture.
Which leads to what I mentioned in the previous post, but let's skip the numbers. Is EPS+thin so tight that it approaches the brick's diffusion values, which means that EPS+thin is no more than 10 to 20 times more open?
KristianH wrote:
I don't have the energy to calculate, but already 45 mm of insulation gives a significant shift of the "cold," which you should be aware of if insulating from the inside.
Otherwise, you take as thick insulation as you can. It is essentially the thickness of the insulation that determines your wall's U-value.