Hi everyone, We have a damp patch under the dining room window. Started out small and is getting bigger. Appears when it is damp or raining and dries out when radiator is on. I have tried re siliconing the window in areas where it had looked to have come away and also repointed a couple of areas where the pointing had gone. It’s still there has anyone any ideas how else it’s getting in? It’s a sandstone cill on the outside (painted). Thanks