Ground source heat pump trenches?

[GB_Groundworks]

quoting on a job to install 250mx1mx1m trench for ground source heat pumps, spec just says lay 100mm sand in trench, pipe and cover with 200mm sand.

should i just use builders sand or sharp sand its only to protect the pipe?

thinking that builders sand gets water logged quiet easyily

and can anyone give me a rough idea of the price of a 20 ton loads, worked on £300 a load in quote. need 75m3 = 120 tons of sand at 1.6 tons a m3.

giles

[seanandruby]

reject sand is what you want. look for your local supplier.
thought ground source did their own back fill.

[Dave_L]

I guess any sand quarry would have this reject sand - they'd be happy to have the business right now - the quarries round here are real quiet.

[lutonlagerlout]

any sort of aggregate you need to get a local quote as it varies so much from region to region,that amount you should get a fair discount
LLL

[Suggers]

Everbody's going mad on ground source heat round here - relatively easy to install into new build - a bugger to install into existing - even if you have the space.
I hear Sainsburys are installing under their new build car-parks - herringbone. The wife's just looked over me shoulder and told me that's ancient news - bugger.

[seanandruby]

i have just used reject sand and also crushed glass for backfilling
G S ducting. will use dtp1 next to form the road.