I have a garden on three levels Astro, slab and slab. Professional? Who fitted it did not include drainage. Water now gathers at the bottom beside house. How can I sort this?
If you can't follow Pauline's advice because you don't know who did the work, then it's difficult to say with so little detail, but first suggestion would be a french drain immediately behind the last drop in level before the house
Does this help?
guy who done it is a cowboy. Said ” no need to worry about rain”
what is a french drain?
With hard landscaping (non-porous) you are going to have drainage issues. The water needs to go somewhere and with your plot sloping towards the house that's where the run-off will gather. If it's surface water then a drainage channel arrangement as in the link below would be the solution however the challenge is having a suitable 'outlet' for the gathered water.
A fench drain is a perforated pipe laid in the ground that leads to either a surface water drain or to a soak away. A soak away is simply a deep pit 1M or more if you can manage it, filled with course rubble or stones that the water can drain into. The excess then leaches slowly into the surrounding ground over a period of days. Its a lot of work.
The idea would be to get the water to your nearest drain, like mentioned above a chanel a couple of inches deeper than lowest point tapering towards your drain.