Paving over waste pipes

[falcs]

Just about to embark on my patio project and have a question.
Having dug up the majority of the area to be paved ready for type 1 to go in, I have come across some of the soil and soakaway pipes that were under the grass (no pre existing patio before I started). My problem is that some of these pipes are at a depth of approx. 125-180mm below what I want to be my new ground level, dictated by the dpc. My belief after much reading of this excellent site is that I need at least 100mm of type 1, then mortar then slab, which is going to be circa 150mm, meaning my type 1 could end up going straight onto the pipes which I presume is not good.
So do I encase in concrete then put shallower type 1 in on these areas, or is there another way?

[r896neo]

When the pipes are that shallow its best to cap over them with concrete for protection more than structural issues.

You can certainly reduce your type 1 depth over the pipes.

Aim for at least an inch or two of type 1 so maybe 75mm of concrete as a capping and 50 of type one.

[falcs]

Would a geomat/grid be of any use? ie leave some of the shingle in that is currently covering pipes, then mat then type 1 etc?

[GB_Groundworks]

Generally anything under 600mm cover is covered with a lean concrete mix to protect the pipe, so cover them over upto the level of your mot and lay straight onto the concrete

[falcs]

Thx chaps, concrete casing it is then!