Substructure Screwing Curtain Facade Permissibility

Hello forum,

I have a question regarding the admissibility of screwing a substructure of a curtain facade:

Situation: The substrate is a relatively loosely set rubble wall made of sandstone. On top of that, as a substructure, a vertical battens with 60cm spacing made of KVH spruce 60x120mm (the 60mm facing the wall). On the outer side of the battens, a 60mm Steico wood fiber insulation board is stapled. The resulting cavities are blown out with Steico-Zell (wood fibers). On top of that, there should be another vertical batten and on the outside a horizontal rhombus cladding. The facade is 3 meters high and spans three walls, 7m, 11m, 4m.

The implementation of such insulation is subject to constructive and also safety-related requirements.

What legal requirements exist for the screws and anchors used to fix the vertical battens for the substructure into the rubble wall? I keep hearing different opinions on this.

Does the anchor need an approval for sandstone? Or must the entire screw connection be a system approved for this situation by the building authorities? Or can anything be used as long as it holds?

A logical explanation I had from a Fischer employee was that a system approved for this situation consisting of anchor and screw _must_ be used, since only in this way data for the calculation are available to determine and possibly prove the durability of the construction.

A carpenter said you could use whatever you want and do not have to pay attention to approvals or anything like that.

How does it behave? What legal regulations apply and what requirements must be followed during the implementation? Can one possibly read this somewhere?

Thanks for your answers!

From my perspective, Fischer is not entirely wrong with the statement. For example, what use is a concrete anchor in sandstone. The carpenter's statement is along the lines of: "We've always done it this way and it held!"

However, if I read above that it is a rubble stone wall, then it probably has little to do with the standard wall from an anchor test. There is also the possibility of pull-out tests by the anchor manufacturer on site, and they recommend a type of anchor (maximum load and/or maximum anchor spacing). In my opinion, this is the best solution for unknown wall types.

Hello hanse987,

"We've always done it that way and it held!"

No, actually even worse, the carpenter did it for the first time.
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There is also the possibility of pull-out tests by the dowel manufacturer on site and them recommending a dowel type (max. load and/or max. dowel spacing). In my view, this is the best solution for unknown wall types.

That's exactly what I meant. Through the pull-out test you get concrete values for durability with which you can then determine the number of required dowels and screws.

But, regardless of whether this makes sense or not: What MUST be done, i.e. which guidelines / laws / regulations must the executing company comply with? MUST it even be calculated or not?

It is always said "according to the state of the art" or "building inspectorate approved" etc., but what exactly applies?

But where are the regulations that must be specifically followed? That would actually have to be the building code or construction regulations. Which part of it applies here, or can you do anything as long as it holds over the warranty period?

Can someone give me a link or something where I can read about this, or – I mean links are prohibited here – a tip on how I can google it?

Thanks![/QUOTE]

Unfortunately, I cannot provide an expert answer, but try Googling: "when do I need an approved anchor" — the second or third result is a list from Fischer about usage for different applications.

Now my layman's opinion. Could someone be injured if the curtain wall falls? Just reading 60x120mm battens, I would answer YES. Then, in my view, an anchor suitable for the application must be used. This can only be one with approval or if there is no approval for the substrate, then one that is selected after an on-site test.

Now my layman's opinion. Could someone get hurt if the curtain wall collapses?

Yes, definitely. One side is 11 x 3 meters. On the south side, a balcony is supposed to be installed above.

What I find strange is that no one can say anything about it or if it can simply be looked up somewhere - by the way, not even my RAW. It must somehow be regulated by law.