Please could someone advise if I can purchase some sort of membrane to place inbetween the logs and the soil as I am replacing log roll that has been 'eaten away' from within and I am hoping to prevent the same happening within the nex few years. Also,is it recommended to dip or paint the lower half of the logs with bitumen/creosote and, finally should they be cemented in?
Don't know about the rest, but don't use bitumen or creosote anywhere near where you want to grow plants - it'll damage them.
I was told if you cement in stops damp, but haven't bothered with the log roll in my garden.
You can get post crete and line the trench with it dry, place log roll in powder and wet - works
Labradouble, All I did with my log roll was to cut up plastic compost bags to size and nail them on the back of the roll, a slight flap to go under the bottom and those edgings to slightly raised beds are still going strong a lot of years later.