Insulation steel beam exterior wall breakthrough

Hello everyone,

first of all, this is my first post here in this forum. Unfortunately, I couldn't find anything suitable for my concern using the search function.

So, in our old building (1954), an exterior wall breakthrough is planned for the installation of a 160 cm wide terrace door element. The structural calculation is available. This is not the first breakthrough we create ourselves, so it will be professionally supported, bearing points considered, etc...

Two galvanized HEB 100 beams placed one behind the other will be used as lintels in the exterior wall. Now I am wondering how to best insulate to avoid/minimize thermal bridges. My current plan is as follows:

- Fill the hollow spaces of the beam with mineral wool or stone wool

- Wrap with expanded metal

- Plaster

My concern now is that the narrow sides of the beam flange, which would then only be plastered, would conduct the cold very well into the interior. A known mechanical engineer advised me to additionally attach a Styrofoam/Styrodur board from the outside over the area of the lintel.

The wall consists of 24 cm Poroton bricks and is clinker-faced on the outside with 6 cm mineral wool insulation in the battens. No other exterior wall insulation is planned for the time being.

I know, a very long text, but I hope I haven't expressed myself too complicated and you can help me

Best regards

Marc

As long as you apply 6 cm of mineral wool insulation on the outside again, that should at least be sufficient on the end face.
With 2x HEB100 and a 24 cm wall, you don't have much space to insulate inside the wall.
Styrofoam, Styrodur, and perimeter boards are too thick.

If I were you, I would use Wedi boards. They have several advantages: they insulate, are pressure-resistant, no reinforcement needed as it is already integrated in the Wedi board. Just stick them onto the beam. I don't know what adhesive is suitable for metal.
If you wrap the beam with expanded metal beforehand, you can simply glue the Wedi board, or the other three materials, onto the expanded metal with adhesive and reinforcement mortar.

Hey,

what exactly do you mean by mineral wool insulation on the outside? From the outside, covering the steel beam across the entire surface? Because between the flanges, about 8 cm of mineral wool is clamped across the width of the beam anyway.

In front, I would rather stick the Wedi board, or did I misunderstand you?

Hi, if I understood the sentence correctly,

Die Wand besteht aus 24 cm Porotonsteinen und ist aussen verklinkert mit 6 cm Mineralwolldämmung in der Lattung.

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 against the outside air, better also additionally against the interior.

Hey,

yeah sure my mistake :P Our entire house is insulated with 6 cm mineral wool under the brickwork, with the EXCEPTION of the extension where the wall opening is now being made. I noticed that when removing the bricks and forgot to mention it here.

My plan now is to basically glue the Wedi board on the outside as a surface-mounted installation and just accept the small protrusion. Thanks for your answers!