Cottage 1830 diffusion open

[Awoma]

Hello!

I am facing different material choices that I hope you can help me with.

The cottage currently has no insulation, all interior walls will be torn down and redone. I've read about several different material options, all need to be able to absorb and release moisture.

I plan to build the walls with (from the outside in) 1. Wind barrier paper, 2. Flax insulation, 3. Vapor barrier. Here, I get a bit stuck among different options, the most common might be OSB and then plasterboard. However, I'm not sure if these are sufficiently breathable.

I've read a bit about fiber plaster and clay board; does anyone have personal experience with these? Or is it okay to buy OSB and plasterboard - is it breathable enough?

 

[surris]

Hello!

I am facing different material choices that I hope you can help me with.

The cottage today has no insulation, all the interior walls will be torn down and redone. I have read about several different material alternatives, all need to be able to absorb and release moisture.

I plan to build the walls with (from the outside) 1. Wind barrier paper 2. Fiber insulation 3. Vapor retarder. Here I get a bit stuck among different options, the most common might be OSB and then plasterboard. However, I do not know if these are sufficiently vapor permeable.

I've read a bit about fiber plaster and clay board, does anyone have personal experience with these? Or does it work to buy OSB and plasterboard - is it breathable enough?

Hi,

I assume you're talking about the exterior walls and not the interior walls? And that there is timber between the wind barrier paper and the fiber insulation?

How thick a layer of fiber insulation are you going to apply?

 

[oliven1]

Hello!

I am facing different material choices and I hope you can help me.

The cottage today has no insulation, all interior walls shall be torn down and redone. I’ve read about several different material alternatives, all need to be able to absorb and release moisture.

I'm thinking of building the walls with (from the outside) 1. Wind paper 2. Linen insulation 3. Vapor barrier. Here, I'm a bit stuck among different options, the most common might be OSB and then gypsum. However, I'm not sure if these are sufficiently diffusion-open.

I've read a bit about fiber gypsum and clay boards, does anyone have personal experience with these? Or does it work to use OSB and gypsum - do they breathe enough?

what do you mean would be a problem with gypsum and OSB?
would work excellently.

even plastic would work fine on a timber frame if you get it right

 

[Awoma]

Hello,

I assume you're talking about the exterior walls and not the interior walls? And that there's timber between the weather barrier and flax insulation?

How thick a layer of flax insulation are you going to put on?

Yes, or I'm thinking timber, weather barrier, 50mm insulation, vapor barrier, possibly OSB and plasterboard?

Or am I completely off track?

what do you mean would be a problem with having plasterboard and etc.?
would work perfectly fine.

even plastic would work well on a timber frame if you can get it to

what do you mean would be a problem with having plasterboard and etc.?
would work perfectly fine.

even plastic would work well on a timber frame if you can get it to

That it's not sufficiently diffusion open, as it currently relies on natural ventilation.

 

[surris]

Yes, or I'm thinking timber, wind barrier, 50mm insulation, vapor barrier, possible OSB and plasterboard?

Or am I completely wrong?



That it's not sufficiently diffusion open, as it is currently self-ventilating.

With that amount of insulation, you can skip the vapor barrier; you get enough vapor resistance in the board materials, and the dew point won't fall in the wall. Seal the timber logs with linden caulking too. If there is wind barrier on the outside, skip the wind barrier in that case.

 

[oliven1]

don't keep up what difference would it make because of natural ventilation?
you can have plastic in a house with natural ventilation

 

[Daniel 109]

With that amount of insulation, you can skip the vapor barrier as you get enough vapor resistance from the panel materials and the dew point won't be in the wall. Seal the logs with lindrev as well. If there's wind barrier paper on the outside, then skip it in that case.

What do you mean by dew point? It can't be the normal definition.

 

[surris]

What do you mean by dew point? It can't be the normal definition.

The point where the warm air meets the cold air and the water vapor precipitates as water.

 

[Daniel 109]

Are you going to have counterflow air in the wall? That doesn't sound good.

 

[oliven1]

both of you @surris & @Daniel 109 are mixing up the concepts.

the dew point is simply the temperature at which the air can no longer hold the moisture as vapor and releases it as free water in the form of condensation.

it can be in both cold and warm temperatures, but what matters is the decrease in temperature, all else being equal.

 

[Daniel 109]

What concepts am I mixing up?

 

[oliven1]

What concepts am I mixing up?

all of them,

you write that the dew point cannot be the normal definition which it is.
you write that the counter-directed fire in the wall is not good, of course you have a place where cold air meets warmer air just like Surris says

 

[Daniel 109]

No, you definitely shouldn't have flows of warm and cold air in the wall.

When talking about the dew point of air, it indeed refers to the temperature at which moisture in the air condenses. When talking about the dew point in a wall, it usually refers to the place where the temperature matches the indoor air's dew point.

That point always ends up in the wall.

 

[oliven1]

No, you definitely should not have flows of warm and cold air in the wall.

When talking about the dew point for air, it indeed refers to the temperature where moisture in the air condenses. When discussing the dew point in a wall, it usually means the location where the temperature corresponds to the indoor air's dew point.

That point always ends up in the wall.

unfortunately, you are wrong on both points.

you will always have air with different temperatures in a wall, it is one of the wall's most important functions.

dew point in a wall has nothing to do with "the temperature corresponds to the indoor air's dew point." it can't even be said like that, it is completely illogical. The dew point in a wall is simply the dew point for the wall, the point in the wall where the air cannot hold the moisture in the form of vapor and releases it in the form of water.

 

[Daniel 109]

If you have a dew point in the wall with that definition, it is seriously misconstructed.