There is definitely no tanking (waterproofing) on the back of the wall and the water is coming through and blowing the render off. You need to excavate the soil away from the back of the wall, and allow it to dry out. You then need to paint the back of the wall with a tanking paint - I usually specify Permaseal. You'll need to remove all the render from the front face and seal it with an outdoor sealant. I'd also install a French drain at the back of the wall - you can put it just below soil level so that you can put the lawn over the top. A french drain is a simple construction and if you Google it you'll find many sites telling you how to do it. Once the wall is dry you can then either re-render or clad the front face.

Do you mean pebble mosaic? I have thought of doing some craft project but I am not sure if I would want to do a scale of 50m2. I like the idea but ideally I want a smooth or slightly riven surface for practicality especially where the garden table and chairs will be. The 1st patio will become a chilling area with garden sofa and Outdoor BBQ kitchen. I was thinking blue/black slate flooring to recall the blue/black bricks on the planters and pond but I am worried that the dark floor will overpower the effect.

Hello, Looks like you have a very nice space there! Regarding your narrow border, I would suggest some pleached trees to go in there (such as in the picture below) . They are great to give you some height and do not occupy a lot of space at all. As Sonia said, you can attempt to amend your soil by digging some grit it, but the most straight forward solution in my view is to choose plants that tolerate the conditions of a heavy clay soil. Roses, some varieties of crab apples and the evergreen holy tree (which is easily found in the pleached format) are some ideas. Drip irrigation is a good idea, but heavy clay soils are very water retentive (usually puddling is a problem with this soil and not dryness). As Sonia said, newly planted plants do need more watering to stimulate the roots system to establish in the new location. The idea of putting a sofa do block children's access to the change of level in the patio is good as it will add to the cozy feel you are after. A wooden pergola on top of it as the ones that you suggested is a very good idea. You can also get retractable roofs to give you the possibility of shelter from the sun. Sonia's idea of planting scented climbers on the pergola is a very good one as well. Another idea is to add a brick edging around your patio to mark the edges and make the change of levels a bit more obvious and secure. Another idea for your gate are is to select plants that can grow through the gravel layer (provided that the gravel is not on top of concrete). As Sonia pointed out, potted plants do require much more watering than plants on the ground (once these are established). So this would be a good alternative. I provide planting plans, which provide you with planting that is suited to the garden conditions and to your preferences and needs. This service can be done online. If this interests you, please get in touch.

Soon after purchasing my house I discovered, near the house, a lot of water under old rotten and disintegrating decking I had just removed. Rather than deal with the problem I surmised that the previous owners had put down the decking hoping the problem would go away. It was remote from the household drains and although I already knew they needed replacing I also knew they couldn’t be responsible. It took a while to work out but it turned out I had a leaking highways drain running right through my garden. Every time it rained a sizeable amount of water from the road spilled into my garden much of it near the footings of my house. Escaping water can cause a whole lot of problems.