What does 'penetrating damp ' mean?

Chapter 20: What a Property Survey Really Means

"... see a penny of work from it. - Damp - There are two types of damp: Rising Damp - damp coming up from the ground penetrating damp - damp coming through the wall Types of Damp - Rising and Penetrating Rising dampDamp coming through at ground level. There..."

"... it can be too time consuming to check some of the most common work. Let's take an example of penetrating damp found underneath a window which is coming from a crack between the outside brickwork and the window frame. The work to fill in the crack might cost £200 so you would feel confident in asking the vendor to put it right. But he hires a cheap builder who uses low quality materials and provides a receipt confirming the work is done. It may have been done to such a standard that you will have to undo and redo the work yourself at some stage in the near..."