Exterior wall brick + interior walls lime sandstone

Supplement:
It is only a sliding joint if the described anchors are vertically movable on an anchor rail. In your case, it seems to be rigid anchors. Whether this is sufficient for the different building materials and the expected shrinkage/creep dimensions should be assessed by a professional who makes a living solving such problems.

I would not take the construction error with the KS lightly. Get yourself DIN 1053-1, especially section 6.7.

What does the architect and, if applicable, the examining structural engineer say?

Hello Allrounder,

thank you very much for your explanations.
Question: what would you do in my place if you actually find an exterior wall made of brick and load-bearing interior walls made of calcium silicate?
With the further condition that the sliding joint is present, and a wall groove is made.
Have it torn out?

Regards, Augustus

moin Augustus,

I would first have a clarifying conversation with the architect and construction manager about how the contractually non-compliant behavior came about and already hint that the radical solution = tearing out is certainly an option. Let them explain to you exactly how the error can be corrected.

Against appropriate compensation and the proper connection of the interior walls to the exterior walls (for this, get the aforementioned DIN, which fits your case exactly in section 6.7), you could possibly be willing to refrain from demolition. The company will have to swallow that first. After all, they did not stick to the contract and created unnecessary problems.

The trowel cut alone does not eliminate the general problems caused by the different shrinkage/creep/moisture behavior of the two building materials: thick Poroton wall with high moisture exposure (because it is an exterior wall) VS. thinner KS wall, which as an interior wall should always be drier. This entails a constant risk of cracking, which must be countered with additional constructive measures; unlike if – as planned – it had been built homogeneously with one building material.

Regards
Allrounder

PS:
The anchors you described are probably not a sliding joint, unless the anchors are vertically movable in an anchor rail!

Hello Allrounder,

Your commitment here in the forum is admirable but in this thread you are using "cannons to shoot sparrows".

I would first have a clarifying conversation with the architect and site manager about how the contract-violating behavior came about

That is correct and recommended; deviations from the BB must not be made without compelling reasons (geology, statics, or also municipal requirements) and "should" not be made without consultation with the client; whereby in most contracts the site manager is released by the client for this.

and already hint that the radical solution = tearing out is definitely an option. Let them explain exactly how the fault can be corrected.

That will probably harm the OP rather than help, because - with proper observance of the DIN for this case - there is no reason to tear out the KS interior walls again. The KS industry has been offering tried and tested products for years that help prevent cracking due to different drying behavior of hollow bricks and KS.

Provided that the plasterer knows his job, there is no objection to building the interior walls from KS; on the contrary, it corresponds to common practice, which takes into account the client’s desire for peace in his own four walls. Basically, however - and here I agree with you - a material mix of the stones should remain the exception whenever possible.

With the anchors you describe, it is probably not a sliding joint, unless the anchors are vertically movable in an anchor rail!

In my opinion, these are not anchors, but the usual metal strips as can be found on any shell construction.

Rhenish greetings

Hello construction expert, nice to hear from you! I greatly appreciate your contributions because of your balanced and competent manner. I only mentioned the demolition as a noteworthy option compared to the BU, not as a recommendation. In my experience, it sometimes provides a stronger negotiating position if you do not rule out the worst case from the outset. The client should just know exactly what they are getting into and be able to at least roughly understand the technical requirements. A skillful plasterer alone would not suffice for the DIN. It already depends on the constructive wall connection with the "anchors made of stainless flat steel" (as is the designation known to me from the KS industry). Whether anchors, straps, or anchor change, it seems we are talking about one item. The client should keep a close eye on that together with the structural engineer and architect and always know what they are getting into. Regards Allrounder