The porch on my house has been built of breeze blocks (hollows) forming an 11" cavity wall laid directly onto a concrete slab. Each leaf of the wall sits directly on a 150mm dpc strip - i.e. not on a raised row of bricks. As a result, water seeps across the base of the outer blocks, above the 'dpc', and into the inner ones. What is the best way of damproofing the inner wall, or more precisely, will silicone cream injection work to form an impenetrable layer above the existing dpc? Cheers!