weed control

So I was meant to relay our garden slabs nearly over a year ago now however haven't had the time to get to it until now, as the weather is getting better. Had a separate post on a different query (https://www.diynot.com/diy/threads/laying-paving-slabs-in-garden.615167/). Hopefully as now I am...

I would like to hear people's advice on how or whether I fill the gap between external wall and ground as in the photos. It is in my garden and I can see a layer of black thick sheet coming out from the gap, which I assume is DFC? There are lots of soil both above and underneath the sheet and...