Are perimeter insulation boards glued or dowelled in the ground area?

We have received an extension. Here, the construction company placed long perimeter insulation boards (approx. 2700 by 1000mm) vertically against the exterior basement wall in the ground and drilled once at the top. They partially foamed the joints.

Is this common? For me, the remaining exterior basement walls (existing building) will be insulated. Smaller boards with a stepped tongue and groove would probably be considered here. The boards are usually installed horizontally. Should these boards (e.g., Perimeter B-3000 EPS 035 PW (format 1250 x 625)) be glued? Before that, the wall will receive a new thick coating.

You no longer use dowels, you glue, and if the gaps are too large, you foam. Of course, only to a certain extent, but show me a picture.

One glues, provided the substrate allows it. If unsure, glue first, then do a pull-off test, then if necessary additionally plug.

fully or only partially (so that the main thing stands out). With the insulation itself, you do not achieve that the insulation itself also does not allow water to pass through. That is supposed to be done by the thick coating (in my case WeberSuperflex 10 2k).

I have dealt with this topic VERY thoroughly.

The manufacturers prescribe a full-surface adhesion depending on the load situation (e.g., groundwater). In practice, however, it is handled very differently. Since construction usually does not follow the manufacturer's specifications, all possible variants can be found. Usually, these also do not cause any problems.

The perimeter insulation can also be fixed exclusively with dowels without glue or bitumen; the earth pressure presses it so tightly that it is never washed out by water, as long as there is no stagnant water or groundwater.

Personally, I recommend spot adhesion in addition to dowels. Then you are on the safe side and the effort is absolutely reasonable.

There are many other areas in construction where real mistakes are made. How the perimeter insulation is attached is, to put it mildly, pretty irrelevant.

full-surface or only spotwise (so that the main thing lifts). With the insulation itself, you do not achieve that the insulation itself also does not let water through. That is supposed to be done by the thick coating (in my case WeberSuperflex 10 2k).

For this, you normally have a white tank in new construction, which is absolutely waterproof and also vapor-tight with at least 20 cm. The bitumen coating is only double security in case there were mistakes during concreting.