Process for preparing jointing foam

A process for forming an in situ jointing foam wherein two components A and B for forming the jointing foam are intimately mixed at the time of application to a joint comprising storing in a first compartment of a 2-compartment cartridge container as a first component A a thixotropic slurry containing 30 to 70 wt. % of gypsum dihydrate and 70 to 30 wt. % of water;

• and storing in a second compartment of the 2-compartment cartridge container as a second component B diphenylmethane-4,4'-diisocyanate pre-polymer, diphenylmethane-4,2'diisocyanate pre-polymer, 2,4-toluylene diisocyanate, 2,6-toluylene diisocyanate, or a mixture thereof;
• intimately mixing at the time of application to a joint 40 to 60 wt. % of the component A aqueous slurry of said first compartment with 60 to 40 wt. % of the component B of said second compartment wherein the weight percentages are with reference to total mixture;
• and introducing the intimate mixture into a joint and allowing the mixture to harden.