We have water coming through the garage wall which is single brick. This is at least 40 years old. The water is running down the wall and then coming in through various mortar joints, the worst is the course with the damp course in it. There are no obvious holes in the mortar but it seems to have become porous. How can I water proof this wall ? Is there way of proofing the existing mortar ? I have put a rag on the outside to çatch the worst until the rain stops .
