correct sand for backfilling trench?

[mattu27]

Hello all, nice simple one for someone in the know. We've put a new water mains supply in and have bedded and covered in 75mm of building sand to protect from rocks etc.

Should the rest of the trench be backfilled in the same building sand. Or should it be sharp sand?

We are block paving after if it makes a difference? Could type 1 stone be used?

Excavated material was red clay which was like playdoh it was that wet, this has since been took away on a grab.

I have seen fill sand mentioned but the builders merchants don't sell or know what it is when I ask for it.

Thanks

 

[23vc]

As long as the pipes well buried and protected, put whatever you like in there. Any sand, or soil

 

[^woody^]

or soil

As long as you pick out the stones first.

 

[mattu27]

Would building sand be strong enough if compacted in Layers? I have type 1 if it's more suitable. Will be driving/parking right over that ooint in the future. Thanks

 

[23vc]

As long as you pick out the stones first.

Yeah, thought the pipe was buried in sand quite a way below it tho. But yeah.

 

[mattu27]

Yeah, thought the pipe was buried in sand quite a way below it tho. But yeah.

Have gave it a good surrounding of Building sand with pea gravel around the connections.

My worry is that the clay we dug out of the trench was very soft as the boundary box has been leaking for some time. Would like to backfill with the best material I can if possible.

 

[Ian H]

Type 1

 

[mattu27]

Type 1

So would you say sand around the pipe to about say 300mm then type 1 for the rest?

I'm going out in the morning to get some more sand. Keep thinking that sharp sand would be better as the grains lock together.

 

[Ian H]

I’d have about 3” of sand over the pipe, compact it gently with my foot then backfill with good stuff.

 

[mattu27]

Thanks for the replies. Just waiting on Severn Trent to backfill their bit so I can do mine.

Tackling the manhole brickwork now, got to raise it up a course. What mortar mix is best? Seemed rock hard when I've been chipping it off so guessing a strong mix.