Hi! I am wanting to do a paved patio of about 5x3m. It will be against the back wall of the home which on the other side is a crawl space. The backyard slopes into the house and I want to make sure I'm doing this right and not going to cause damage/water problems to the foundation of the house or the crawl space. Do I need to put a waterproof barrier between the pavers and the brickwork? Or anything else between the pavers and brick work or can I lay them right up against the brick? On the other side of the pavers I will have a small retaining wall because of the backyard slope. If I slope the patio slightly towards the retaining wall to make sure water from the patio surface isn't running into the foundation, should I add a drain along inbetween the patios and retaining wall? Any other advice much appreciated! Thanks