Fixing wall purlin of terrace roof to house wall

Hi!

I am about to build my terrace roof. I am still undecided about how to fasten my 8x20 wall beam to the house wall.

About the house wall:
- 17.5cm aerated concrete
- 16.0cm insulation
- 4.00cm air gap
- 11.5cm facing brick

However, it will not be fastened in the aerated concrete, but directly above the 6.5m terrace window (and the exterior roller shutter housing) in the lintel. Since the building documents (we only bought the house, did not build it) do not specify the material of the lintel, I do not know whether I am fastening the terrace roof into concrete, aerated concrete, or something else. The house is from 2012, and there were already alternatives to reinforced concrete lintels at that time.

For this reason, I tend to go for the "classic" fastening: M16 threaded rod, 530mm long, made of A4 stainless steel, fixed with Fischer FIS VL 300 T injection mortar. Along with this, a 40cm long metal mesh sleeve.

First question: This would be the standard solution for aerated concrete. But is this also suitable if the lintel is made of concrete?

As a second option, I am considering bolt anchors of the same length. I would then skip the injection mortar. However, I seem to remember that these bolt anchors are not approved for aerated concrete. So if the lintel is, contrary to expectations, not made of concrete, I would be in trouble.

Second question: Is my memory mistaken, or is this correct?

Third question: Can you think of any alternative fastening methods?

Fourth question: Is the injection mortar I mentioned above the right one? There are so many variants; maybe someone here is familiar with it.

Best regards

For the house wall:
- 17.5cm aerated concrete
- 16.0cm insulation
- 4.00cm air gap
- 11.5cm facing brick

For this reason, I tend towards the "classic" for fastening: M16 threaded rod, 530mm long, made of A4, fixed with Fischer FIS Vorlauf 300 T injection mortar. Additionally, a 40cm long metal mesh sleeve.

That already gives a proud 31.5cm as a non-load-bearing layer, meaning the M16 threaded rod has to hold everything against bending. If you don't want to glue in a threaded rod every 40cm, I would rather tend towards M24.

First question: This would be the standard solution for aerated concrete. But is it also suitable in case the lintel is made of concrete?

Adhesive anchors can also be used in concrete. However, the mesh sleeve is actually only needed in the area of the bricks, air gap, and insulation.

As a second option, I have bolt anchors of identical length in mind. I would then save the injection mortar. However, I seem to remember that these bolt anchors are not approved for aerated concrete. So if the lintel is unexpectedly not concrete, I would be in trouble.

Second question: Is my memory mistaken, or is this correct?

To my knowledge, there are no expansion anchors or concrete screws in this length from either Hilti or Fischer.

Third question: Can you think of any alternative fastening methods?

The only thing I can think of would be to install the patio roof completely separated from the building, i.e., with wooden posts in front of the facade.

Fourth question: Is the injection mortar I specified above the right one? There are so many variants; perhaps someone here is familiar with this.

According to the homepage and approval, at least aerated concrete is listed as a substrate.

Thank you. That already gives me a lot of clues!

That already gives a proud 31.5 cm as a statically non-load-bearing layer, meaning the M16 threaded rod has to hold everything against bending here. If you don't want to glue a threaded rod every 40 cm, I would rather tend towards M24.

Here I have to intervene again: If I also have a sieve sleeve and injection mortar in the area of the clinker, the threaded rod also rests on the facing shell there. It therefore transfers transverse forces into the clinker wall, which in my opinion is unproblematic. Only compressive and tensile forces must be avoided in facing shells. If my line of thought is correct, then there would still be 20 cm of free thread length between the clinker and the masonry, but the bending load would be greatly reduced by the additional support.

I just don’t know whether to attach the patio roof to concrete, aerated concrete, or something else.

Just do a test drill, then you will know for sure whether it is concrete or aerated concrete. Afterwards, you can consider the fastening options.

The only thing I could think of would be to place the terrace roof completely separated from the building, that is, with wooden supports in front of the facade.

That's how I would do it too. In theory, the vertical supports could also be embedded into the insulation.