Marcinho14053 Nov 2016 19:28Hello everyone,
this is my first post in this forum. Unfortunately, I couldn’t find anything suitable for my issue using the search function.
We have an exterior wall in our older building (built in 1954) where we plan to create an opening to install a 160 cm (63 inches) wide terrace door element. Structural calculations are available. This is not the first opening we are making ourselves, so proper support and bearing points are being taken into account.
Two galvanized HEB 100 steel beams will be installed as lintels in the exterior wall, placed back-to-back. Now I am wondering how to best insulate to avoid or minimize thermal bridges. My current plan is as follows:
- Fill the cavities of the steel beam with mineral wool or stone wool
- Wrap with expanded metal lath
- Apply plaster
However, I am concerned that the narrow sides of the beam flanges, which would only be plastered, might conduct cold air directly into the interior. A mechanical engineer I know suggested additionally attaching a polystyrene or extruded polystyrene (EPS/XPS) board on the outside over the lintel area.
The wall is made of 24 cm (9.5 inches) Poroton blocks and has a brick veneer on the exterior with 6 cm (2.4 inches) of mineral wool insulation installed in the battens. No other exterior wall insulation is planned for now.
I know this is quite a long message, but I hope I haven’t made it too complicated and that you can help me.
Best regards
Marcinho1405
this is my first post in this forum. Unfortunately, I couldn’t find anything suitable for my issue using the search function.
We have an exterior wall in our older building (built in 1954) where we plan to create an opening to install a 160 cm (63 inches) wide terrace door element. Structural calculations are available. This is not the first opening we are making ourselves, so proper support and bearing points are being taken into account.
Two galvanized HEB 100 steel beams will be installed as lintels in the exterior wall, placed back-to-back. Now I am wondering how to best insulate to avoid or minimize thermal bridges. My current plan is as follows:
- Fill the cavities of the steel beam with mineral wool or stone wool
- Wrap with expanded metal lath
- Apply plaster
However, I am concerned that the narrow sides of the beam flanges, which would only be plastered, might conduct cold air directly into the interior. A mechanical engineer I know suggested additionally attaching a polystyrene or extruded polystyrene (EPS/XPS) board on the outside over the lintel area.
The wall is made of 24 cm (9.5 inches) Poroton blocks and has a brick veneer on the exterior with 6 cm (2.4 inches) of mineral wool insulation installed in the battens. No other exterior wall insulation is planned for now.
I know this is quite a long message, but I hope I haven’t made it too complicated and that you can help me.
Best regards
Marcinho1405
As long as you apply 6cm (2.4 inches) of mineral wool insulation on the outside again, that should be sufficient at least on the front side.
With double HEB100 beams and a 24cm (9.5 inches) wall, you don’t have much space for insulation inside the wall.
Styrofoam, extruded polystyrene (XPS), and perimeter insulation boards add too much thickness.
If I were you, I would use Wedi boards. They have several advantages: they provide insulation, are load-bearing, and don’t require reinforcement because it is already integrated into the Wedi board. Just glue them directly onto the beam. I’m not sure which adhesive is suitable for metal.
If you wrap the beam with expanded metal mesh first, you can simply bond the Wedi board—or the other three materials—to the mesh using adhesive and reinforcing mortar.
With double HEB100 beams and a 24cm (9.5 inches) wall, you don’t have much space for insulation inside the wall.
Styrofoam, extruded polystyrene (XPS), and perimeter insulation boards add too much thickness.
If I were you, I would use Wedi boards. They have several advantages: they provide insulation, are load-bearing, and don’t require reinforcement because it is already integrated into the Wedi board. Just glue them directly onto the beam. I’m not sure which adhesive is suitable for metal.
If you wrap the beam with expanded metal mesh first, you can simply bond the Wedi board—or the other three materials—to the mesh using adhesive and reinforcing mortar.
Marcinho14054 Nov 2016 20:32Hey,
what exactly do you mean by mineral wool insulation on the outside? Do you mean applied continuously over the steel beam from the outside? Because about 8cm (3 inches) of mineral wool is already compressed between the flanges across the width of the beam.
For the front side, I would rather suggest bonding the Wedi board, or did I misunderstand you?
what exactly do you mean by mineral wool insulation on the outside? Do you mean applied continuously over the steel beam from the outside? Because about 8cm (3 inches) of mineral wool is already compressed between the flanges across the width of the beam.
For the front side, I would rather suggest bonding the Wedi board, or did I misunderstand you?
Hello,
if I understood the sentence correctly,
the wall is insulated with 6 cm mineral wool insulation.
The Wedi boards are available in different thicknesses. The steel beam in the exterior wall should be insulated at least from the outside air, and preferably also from the interior side.
if I understood the sentence correctly,
Marcinho1405 schrieb:
The wall consists of 24 cm Poroton bricks and is clad on the outside with 6 cm mineral wool insulation in the battens.
the wall is insulated with 6 cm mineral wool insulation.
The Wedi boards are available in different thicknesses. The steel beam in the exterior wall should be insulated at least from the outside air, and preferably also from the interior side.
Marcinho14057 Nov 2016 18:12Hey,
yes, of course, my mistake :P Our entire house is insulated with 6cm (2.4 inches) of mineral wool behind the brick cladding, except for the extension where the wall opening is now being made. I noticed this when removing the bricks and forgot to mention it here.
My plan now is to glue the Wedi board on the outside as a surface-mounted layer and accept the small protrusion. Thanks for your replies!
yes, of course, my mistake :P Our entire house is insulated with 6cm (2.4 inches) of mineral wool behind the brick cladding, except for the extension where the wall opening is now being made. I noticed this when removing the bricks and forgot to mention it here.
My plan now is to glue the Wedi board on the outside as a surface-mounted layer and accept the small protrusion. Thanks for your replies!
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