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We're in the process of planning an extension and part of the building works will be to sort out some landscaping issues as well as some internal damp problems caused by high exterior ground levels. The site is complicated, overall it slopes quite a lot and the detached garage is 465mm above the house. We are trying to achieve: Lower the patio ground levels. I've dug a trial trench around the property and the internal damp now seems to be under control Have a multi level patio as the whole site slopes downwards but we want the areas to be usable for a seating area Finished surface to be yorkstone pavers which will finish a minimum of 150mm below DPC and floor levels All existing rainwater connects to combined waste and BCO has agreed that future rainwater can also join to this as there is no place for a soakaway or any other alternative The building is grade II listed and they are very fussy about changing anything in the existing structure but have agreed to allow channel or french drainage Drainage will most likely be ACO Hexdrain Current plan is the below which looks complicated but makes every effort to move the water away from the old damp house towards the garage which is much (465mm) higher so will be way below DPC. Some pictures to show the site Trial trench around property to reduce damp Looking towards where the new extention between the two buildings will be Upper Patio with gates Just looking for advice on whether this makes sense or if I am over-complicating it with my nerves over the damp issues?

We are looking for some help from anyone with experience of MBC slabs. Its the order of doing things that is confusing us. We believe we need a land drain. We will also have surface water drainage. We have been advised by a drainage contractor to do the drainage (foul and surface inc soakaways) after MBC put the frame up, so probably after the roof is on and the rainwater pipes in place? Maybe before the render because of dirt? So is the best order broadly as follows? Dig foundations, compact hardcore MBC slab MBC frame Roof / windows Drainage (foul, surface, soakaways) plus other service trenches Render / cladding Where does the land drain fit into all this? It seemingly is supposed to go where the hardcore is around the slab. So do we dig that out again (when we do the other drainage) or do we put it in at the same time as compacting the hardcore. Opinions please. And thank you.