Soakaway q - Backfill q

Rick · Post: # 81013Post **Rick** Tue Jul 24, 2012 3:20 pm

Fitting a number of Polystorm Lite soakaway crates. (great deal as only Â£9 each)
As shown on :
Soakaways page

Just wanted to confirm ... blind bottom of hole with 100 sand ... lay in woven Geotex, place crates ... attach feeder pipes, then wrap with Geotex ... do I need to tie to pipes (cable ties ?)
I then backfill with 100mm sand ... no clean stone used as you would for land drainage trenches ?

When I back fill over the top of sand layer ... no Geotex? .... wonâ€™t it mix ? .... or doesn't it matter.
I guess I am going to have to use some form of temp shuttering to backfill sand on sides

local patios and driveway · Tue Jul 24, 2012 4:19 pm

Dig hole, lay sand screed, cable tie crates together, wrap fully in geotextile. You could use ties to hold terram in place. Throw the lot in the hole. Connect pipe using cable ties if you must but you dont need to. Back fill round crate and on top. Put kettle on

Rick · Post: # 81019Post **Rick** Tue Jul 24, 2012 4:55 pm

local patios and driveways wrote:" Back fill round crate and on top. Put kettle on"

with 100mm of sand ... and no stone ?

hole is a lot bigger than 100mm all rouind ... is there a technique here ... or temp sheet in place and remove as you backfill

Tue Jul 24, 2012 5:15 pm

we use 10mm shingle on the base to level and backfill with 10mm shingle
why you would use sand is beyond me?
BCO asked us to do it this way
crates are completely wrapped in geotextile and pipe goes in through hole
btw our crates have special clips to clip them together
cheers LLL

BTW where did you get the crates for Â£9?

Post: # 81036Post **Dave_L** Tue Jul 24, 2012 9:58 pm

Must be some seriously garden-only crates for that money!

Rick · Post: # 81042Post **Rick** Tue Jul 24, 2012 11:20 pm

Dave_L wrote:Must be some seriously garden-only crates for that money!

No you are wrong .. these are 20 Tonne rated crates ....
http://www.polypipe.com/wms/products/polystorm-lite

Rick · Post: # 81043Post **Rick** Tue Jul 24, 2012 11:21 pm

lutonlagerlout wrote:BTW where did you get the crates for Â£9?

I bought them from local branch of BSS Plumbing ... think they are items they wish to clear off stock.

Post: # 81052Post **Dave_L** Wed Jul 25, 2012 5:38 am

I'd buy a truckload for that money!

Wed Jul 25, 2012 7:07 am

20 tonne per square metre
we pay about 30 quid each for them
LLL

Rick · Post: # 81066Post **Rick** Wed Jul 25, 2012 12:52 pm

so my Â£9 + VAT per crate was a good deal then

Rick · Post: # 81067Post **Rick** Wed Jul 25, 2012 1:04 pm

lutonlagerlout wrote:we use 10mm shingle on the base to level and backfill with 10mm shingle why you would use sand is beyond me?

I was going to use 30mm clean stone ... as I will use that in drainage trenches ..
I looked on Polypipe web site and spoke to their Tech rep ... their recommended 'practise' is 100mm of sharp sand all round.
This is their Tech doc:

?Polystorm

or as that is a big doc ... this is the relevant wording:

5.3.5 Lateral backfilling
Backfill around the sides of the encapsulated units, forming a 100mm thick layer of coarse sand or Class 6H selected granular material immediately adjacent to the cells. Where required, remaining excavated areas around the units should be
backfilled with Class 6N or 6P selected granular material, in accordance with MCHW, Volume 1, or similarly approved specification.
-----------------

I will wrap in woven Geotex first.

Is it normal practise to just backfill on top of sand .. or add another Geotex layer to prevent backfill mixing with sand