Tuesday, 24 October 2017

How Much Weed Membrane ?

The question of how much weed membrane or plastic to cover the new plot once cleared, if I got it, is something that I have been pondering for a while. So first a decision re material and then about the size of the sheets to use. 

On Spencer Road the decision was relatively simple, a long rectangular plot 20m long and 5.5m wide, I went for a couple of very large tarps 7.5m x 5m and there was already some plastic on the plot, however with plot 1 its a weird shape on plan. Tarps where cheap and I was looking for a quick and dirty solution.  

Damp proof membrane can be purchased however it's got no reuse value once the plot has been dug and the infrastructure or paths and beds ultimately go in and is similar in cost to weed membrane, so I discarded the DPM route. 

Weed membrane appears to be more expensive the wider the rolls are, they come in 1m, 1.5m 2m, 3, and 4m widths 

2m wide x 100m long 100gsm roll are typically selling on ebay between £69.99 - £75.50
2m wide x   50m long 100gsm roll are typically selling on ebay at around £25

I found that if I bought a 2m x 50m roll it was less that half price, plus if I bought 2 number 50m rolls they gave me another 5% off so I ended up purchasing two rolls for £48 so it pays to shop around.

The 2m wide rolls allow me to cut 2.4x 1.2m sheet out of them leaving 800mm which is ideal for the 600mm wide paths as I can tuck the excess in the ground or dress up the raised bed.

I started sketching on the plan how I may possibly lay out the sheets, and also throwing into the equation just where I may start first. I need to get into and sort out the pile of dross in the corner as that's where the shed and greenhouse will go as I have been informed that there are steel barrels originally sunk in the ground to hold water that are still there but have been infilled with soil. So its and ideal location for the shed and greenhouse, I just need to clear and cap.
That's two sheets at around 9m long that will cover that area.   
Three 2.4m beds lengths are 7.2 so if I cut sheets at 7.5m then I can recut the beds and paths membrane out of them as I progressively clear the plot and I can work in strips.

As I have blogged about it before I cut weed membrane sheets with a soldering iron as if you cut it with a knife it frays. In the sketch below a bed and a path is 1.2m + 0.6m = 1.8m and the sheets are 2m wide, so I should be able to dig a slot in the ground and tuck in the sheets along the lengths   

I will define the edge of the plot and I have enough kerb stones to define the bottom (left) boundary so that when the maintenance contractor comes they have an edge to work and strim to.

The weed membrane has been ordered and hopefully this weekend my bother in law is going to give me a hand to clear using his bush cutter.

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