Sub base query - Old footing and lean mix covering pipes

[Mikey_C]

During the dig out for the final part of my drive I have discovered and an old footing for what was the porch this will be no higher than the sub-base finish height is it ok to leave it there? I also have to cover pipes which are just below formation level with lean mix, the finish height of the lean mix will also be below sub-base finish height, is it a problem?

Should I stick to lean mix to cover the pipes or as this is essentially going to form the sub-base should I make it stronger, say C20/ST4?

Thanks in advance for the advice,

Mike

[seanandruby]

I take it you are using a concrete sub base? therefore the old footing should be ok. because of the low depth of the pipes they will need to be encased in concrete and have movement joints at each collar. c20 should be ok.

[Mikey_C]

I wasn't planning on using a concrete sub-base, I was going for type 1 stone, are they likely to settle differently?

[James.Q]

yes you will get differencial movement but its nothing to panic about

[matt h]

if your pipes are old iron or black polythene advise change now before concreting. ensure pipework sleeved as enters dwelling in accord with latest regulations.

[Mikey_C]

the pipes are the ones I have freshly installed for the linear drainage and some 110mm conduit (polypipe civils) put in to run mains to the front of the drive for lights/gates etc

[matt h]

good luck m8 just ensure good compaction overall and you should have little probs:)