ᐅ Concrete slab partially removed, reinforcement exposed

Hello,

about two weeks ago, the footing slab for our house was poured. Overall, the work seemed very clean and solid, as far as I can tell. This week, the masonry work on the ground floor started. During this, it was discovered that the formwork for the footing slab was not properly squared. As a result, on one gable side, the footing slab slightly protruded below the masonry. The overhang increased along the width of the house from 0 to about 6cm (2.4 inches).

Now the general contractor has chiseled away the overhang along the house width. The reason given was that otherwise the insulation would not fit. The background is that we are also having brick cladding. The bricks will rest on a frost guard approximately 80cm (31.5 inches) deep.

Where the footing slab was chiselled away, the reinforcement is partially exposed. How should this be assessed? Is it sufficient to coat it with bitumen waterproofing?

Reinforcement steel is susceptible to environmental influences and high heat exposure, such as from fire. Therefore, it must be protected by a sufficiently thick concrete cover, which is generally between 2.5 cm and 5 cm (1 inch and 2 inches). The concrete cover ensures

the bond between concrete and steel
corrosion protection
and fire protection.
In the near-surface area, the concrete must be compacted and properly cured to prevent significant cracking. The importance of thorough and adequately long curing is explicitly emphasized in DIN 1045-2. The curing duration is specified in DIN 1045-3 and is determined based on the concrete’s strength development. According to DIN 1045-2, strength development is classified as fast, medium, or slow hardening.

If these conditions are met, a corrosion-protective and alkaline environment is ensured, maintaining the structural performance throughout the entire service life. The concrete cover is defined by the nominal dimension. The minimum concrete cover depends on environmental conditions and the diameters of the steel reinforcement. If the aggregate size exceeds 32 mm (1.25 inches), the concrete cover must be increased accordingly, as well as for surfaces requiring further treatment such as exposed aggregate or textured finishes, and for components with increased fire protection requirements.

The reinforcement detailing is specified in DIN 1045 for concrete, reinforced concrete, and prestressed concrete structures.

Hello.

Strictly speaking, that would mean demolishing the masonry and the foundation slab, and starting everything over. Ouch.

I rather think no – but simply pre-gluing the insulation is also not advisable. Does the insulation in your case also rest on the frost skirt?

Knallkörper schrieb:
That would strictly mean: demolishing the masonry and foundation slab, then rebuilding everything from scratch.

For me, this means: you have a problem that cannot be resolved through a forum. If the construction company says "demolish and rebuild, at our expense," that’s good. If they say something like "we can handle it, we’ve always done it that way," then you urgently (!) need to hire an expert assessor (!). They should evaluate the situation and advise on what needs to be done.

Feel free to update us here afterward!

BeHaElJa schrieb:
I rather think no – but simply pre-installing insulation is also not advisable.. is the insulation also installed on the frost protection strip at your site?

Hello.

Yes, the insulation is also placed "below" on the frost protection strip. This would effectively cover any defects in the foundation slab.