To Wrap or not to Wrap the land drain pipe with geotextile.

[MikeSharp01]

Tomorrow I will be installing the land drain round our slab base and was wondering if I need to wrap the perforated land drain pipe (solid 110mm pipe with a seam of drilled holes) with geotextile or not? The slab design does not call for it but given we are on clay it may stop the silt from getting into the pipe but will it clog up the holes. I will bed the pipe in pea shingle but again this is not called for in the slab design as the whole thing is encased in type 1. Any thoughts anyone?

 

Edited May 24, 2018 by MikeSharp01

[nod]

59 minutes ago, MikeSharp01 said:

Tomorrow I will be installing the land drain round our slab base and was wondering if I need to wrap the perforated land drain pipe (solid 110mm pipe with a seam of drilled holes) with geotextile or not? The slab design does not call for it but given we are on clay it may stop the silt from getting into the pipe but will it clog up the holes. I will bed the pipe in pea shingle but again this is not called for in the slab design as the whole thing is encased in type 1. Any thoughts anyone?

 

When I have put land drains in

i have packed them with pipe bedding or simalar Above and below

 

we are on clay at our current home 

I put land drains at the front and back as the garden regularly flooded 

still working fine some twenty years on

Only draw back is in dry spells Yellow lines spear on the lawns

[bassanclan]

I dug a trench, lined with geotextile, then putpea shingle in, land drain on top,  geotextile over the top then backfill. I figured it would stop clay getting into the shingle and then the pipe.

[PeterW]

Proper way for drainage is as per what @bassanclan says. Wrap the shingle and the pipe in geotex

[ToughButterCup]

Our ground workers didn't..... one reason why part of his bill will remain unpaid until he sorts it out.

[dpmiller]

Smoothbore (twinwall) pipe has less desire to silt up than coilpipe, anecdotally.

[joe90]

When I asked a local land drain expert about my French drains ( we are on yellow clay) he advised against membrane as it can clog with clay silt, he advised against slotted pipe as well, just 50mm stone in a trench, plastic on top ( to stop top soil going into it) then topped with top soil. It’s working very well on my very wet site.

[Mr Punter]

Although it sounds fine in theory, I have seen Terram membrane looking more like DPM after it was in contact with clay for a few wet months.  You could have used it as pond liner.

[Mr Punter]

On the same site, when we excavated we dug up lots of old land drains made of clay pipe. probably 2" external.  They were all completely full of clay.  I would say dig a F.O trench, and chuck in some cheap crushed concrete.  We did not have topography on our side so this led to an old well and we used a 2" pump to pump up the site to a drainage ditch.

[MikeSharp01]

MIxed advice then, I think I will go with the wrapping idea as the slab designer seems to think its not a bad idea and  we will see how we get on. The base of the drain slopes so the general flow will be down hill to the ditch and with lick it will get into the pipe somehow, I believe capillary action should do something as for clay it goes on on an on climbing.