I have a 23sq m kitchen floor extension to do in 600 sq porcelain. Whole floor is new screed on block n beam. However only new half has wet ufh. Recommendations for Ditra mat over the whole area and movement joint where the heating joins? Skirting is going on top so good perimeter expansion on 3 sides. 4 th side is up to full width glass doors. Combined wisdom appreciated. 🧐