The arbitration clause contained in the original construction contract extends its effectiveness also to disputes relating to extra-contractual works or variations performed by the contractor, insofar as they are attributable to the same contractual relationship.
The submission of a counterclaim by a party who has previously raised an objection based on an arbitration agreement does not constitute implicit waiver of such objection, given that the examination of the counterclaim is ontologically conditional upon the non-acceptance of the objection to the jurisdiction of the ordinary court in favour of the arbitrators, the validity of the latter being incompatible with examination on the merits of the counterclaim.
In contracts concluded between professionals, any unfairness of the arbitration clause cannot be raised of the court’s own motion, as the regime of protective nullities provided for consumer contracts does not apply.