Autumn has stopped knocking on the door, it has now turned the key, flung up the latch and wrenched the door open. All season have their beauty and the Stewartia is being as flamboyantly autumnal as any plant could muster. Its display this year is impressive and is one of the plants in my Courtyard Garden just by side of my conservatory.
LTP External Stone Sealer to try. I have not paid for this, but my opinions of it are of course my own. This is water-based and it impregnates the stone to seal it. This bottle was just enough to do the lower course of bricks where the problem occurs. I have waited a week or so until we have had some goodly amounts of rain (and we have had goodly amounts) and it seems to have done the trick. I also think that part of the problem is that the rain does not drain away from the conservatory, my neighbour who has hung his head over the fence and had many a chat with me about this, is of the opinion that I need to have some way of draining the water away from the conservatory. I think this is beyond my skill-less abilities. I am keeping it in mind.