ᐅ Renovation of Older Buildings – Interior Insulation of Exterior Walls
Created on: 10 Feb 2013 18:01
A
andi19Hello,
I live with my sister in a two-family house that is attached to another building. For this reason, I cannot insulate from the outside. So, I have to address the issue from the inside. Since my sister and I are planning major renovations anyway, this shouldn’t be a problem.
Now, for illustration, a brief description of the current situation:
Heating: electric storage heaters
Electrical system: from 1990
Plumbing: from 1990
Windows: from 1995 and 2003
Ventilation: none
Insulation: partly covered with tongue-and-groove boards, with some fiberglass insulation behind them
The heating system will be replaced with a gas heating system using wall-mounted radiators. The electrical system will be updated to modern standards (network, TV, intercom, etc.). The plumbing will be renewed. Some windows will be replaced. I will install decentralized ventilation. I also want to upgrade the insulation, but I am still having some difficulties with that. I have spent several days researching online, but I can’t seem to find a clear solution. Should I use diffusion-open materials or a vapor barrier? Styrofoam or natural materials? Silicate boards to prevent mold? Every manufacturer only lists the advantages of their system, with no real disadvantages.
At first, I considered gypsum plasterboard with attached Styrofoam sheets. Then I read that there is a high risk of mold forming behind the panels, and in case of fire, a large amount of harmful substances would be released. Then I thought about using silicate boards (Multipor). These provide less insulation and can’t withstand heavy loads. They also cost about 25€ per m² (approximately 2.3 USD per sq ft), so they are not cheap. But they do absorb moisture from the air, prevent mold growth, and are fire resistant.
Now I am considering building a timber stud wall in front of the brick wall, filling the cavities with stone wool or wood fiber insulation boards, and then installing plasterboard on top. Plasterboard should also be diffusion-open and able to absorb moisture from the air.
How have you done it? Is there anyone here with expertise in insulation who could help me?
I live with my sister in a two-family house that is attached to another building. For this reason, I cannot insulate from the outside. So, I have to address the issue from the inside. Since my sister and I are planning major renovations anyway, this shouldn’t be a problem.
Now, for illustration, a brief description of the current situation:
Heating: electric storage heaters
Electrical system: from 1990
Plumbing: from 1990
Windows: from 1995 and 2003
Ventilation: none
Insulation: partly covered with tongue-and-groove boards, with some fiberglass insulation behind them
The heating system will be replaced with a gas heating system using wall-mounted radiators. The electrical system will be updated to modern standards (network, TV, intercom, etc.). The plumbing will be renewed. Some windows will be replaced. I will install decentralized ventilation. I also want to upgrade the insulation, but I am still having some difficulties with that. I have spent several days researching online, but I can’t seem to find a clear solution. Should I use diffusion-open materials or a vapor barrier? Styrofoam or natural materials? Silicate boards to prevent mold? Every manufacturer only lists the advantages of their system, with no real disadvantages.
At first, I considered gypsum plasterboard with attached Styrofoam sheets. Then I read that there is a high risk of mold forming behind the panels, and in case of fire, a large amount of harmful substances would be released. Then I thought about using silicate boards (Multipor). These provide less insulation and can’t withstand heavy loads. They also cost about 25€ per m² (approximately 2.3 USD per sq ft), so they are not cheap. But they do absorb moisture from the air, prevent mold growth, and are fire resistant.
Now I am considering building a timber stud wall in front of the brick wall, filling the cavities with stone wool or wood fiber insulation boards, and then installing plasterboard on top. Plasterboard should also be diffusion-open and able to absorb moisture from the air.
How have you done it? Is there anyone here with expertise in insulation who could help me?
Hello,
You need to understand each wall as a system. Ideally, for an exterior wall, the dew point should be located within the masonry. This depends on the materials and wall structure. If you insulate from the inside, for example with Styrofoam or timber framing and drywall, mold will almost certainly start to develop. The reason is that the heat is lost from the inside. The wall cools down, causing condensation moisture that can lead to significant structural damage. If you insulate from the inside, it should be done with silicate boards.
You always have to keep in mind that any subsequent intervention affects the building physics.
You need to understand each wall as a system. Ideally, for an exterior wall, the dew point should be located within the masonry. This depends on the materials and wall structure. If you insulate from the inside, for example with Styrofoam or timber framing and drywall, mold will almost certainly start to develop. The reason is that the heat is lost from the inside. The wall cools down, causing condensation moisture that can lead to significant structural damage. If you insulate from the inside, it should be done with silicate boards.
You always have to keep in mind that any subsequent intervention affects the building physics.
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