Hello,
the following: "... The seller commits to making the contract object ready for occupancy by no later than 02/28/2011 and to complete it fully by no later than 03/31/2011. If exterior work cannot be carried out within this period due to seasonal reasons, the seller must perform it at an appropriate time. The acceptance of the contract object upon readiness for occupancy is not affected by this. Delays in the construction of the object due to circumstances for which the seller is not responsible, e.g., force majeure, strike, execution of special requests, extend the construction period by the duration of the delay."
Then you still have plenty of time
If the above is the entire wording of your contract regarding the extension of the construction period, you have neglected to negotiate a compensation payment per day of delay. However: if the handover deadline is exceeded due to the current and likely still ongoing weather, you have no claim for damages anyway => force majeure.
Aside from the fact that the completion of the exterior facilities is in my opinion negligible, it looks different if the construction can be completed independently of the weather
can (there are no delays due to the exclusions) and there are still "significant" exceedances of the contractually agreed construction period. Case law always decides on a case-by-case basis, whereby it must be taken into account that you can by no means claim an entire rent as damages.
If in the new year the construction period is exceeded, it is necessary to name the reasons for this and – if the fault is undoubtedly to be found with the construction company – you should create a list of the additional costs incurred by you and initially discuss and negotiate this with your construction company. Note: You must be able to prove each damage/additional expense in detail.
Kind regards