SIP extension with screw piles

[Galileo58]

Anyone out there come across this. I have build using a sips floor on screw piles, all under building control. The issue I have is the earth beneath the sip panel floor. The BCO is insisting that I provide hardcore, membrane and concrete under the panels 100 mm in total for essentially weed suppression for an environment with little chance of anything growing and all ventilation requirements exceeded which I believe is total overkill. He has relented a little and says if I can provide him with an 'approved method' he will consider it. The question is does an approved method exist. I've seen many videos of weed mat and gravel but failed in my quest to find any approved documents. Thanks in advance 

[saveasteading]

29 minutes ago, Galileo58 said:

 hardcore, membrane and concrete under the panels 100 mm in total for essentially weed suppression

I don't know what you are supposed to provide under the floor for structural support. J assume hardcore and blinding.

Thus the issue would be of concreting purely to suppress weeds.

 

You certainly don't want weeds growing into your sips panels.

The wrong kind of weed will, indeed, get through materials as tough as tarmac, or joints in panels of concrete.

 

But a concrete slab is excessive.

 

1. Ask your supplier if the panels prevent weeds forcing through.

2. Select a membrane that is proven to be impenetrable to  plants...they exist.

 

I have used the latter to bury Japanese knotweed, successfully.

I can't recall the brand, but try 1. first.

 

 

[Alan Ambrose]

>>> I can't recall the brand

 

It would be fantastic if you could remember which one.

[saveasteading]

A search for root barrier came up with 'root barrier store'. 

If anything says it will resist bamboo or knotweed, then that will do. 

It's quite expensive but not when compared with concrete.

It appears to quote depth where it should say width, suggesting it's foreign???

But shop around.

Normal geomembrane or weed membranes are nowhere near as strong.