In the authors’ opinion, the issue of incorrectly functioning water insulation of foundation walls in the existing buildings in Poland is currently rather common. The paper includes a multicriteria analysis aimed at arranging the selected options of the foundation wall vertical water insulation technology in an existing model historic building using the weighted sum, entropy and AHP methods. Each of the studied solutions was evaluated in terms of the following criteria: costs of construction works, time of execution of construction works, popularity of using particular insulation options by other contractors, durability of the executed insulation and the degree of nuisance of the executed works