Landscape Fabric and Staple Pin Estimator
How many rolls of weed barrier your bed actually needs once the seams overlap, and how many pins to hold it all down. Most people buy enough fabric and then run out of pins on the first afternoon.
The layout
Strips, seams and pin positions for your first area.
The area
Add a section for each separate bed. They are summed for the fabric total.
The roll
Roll sizes are the common commercial widths and lengths.
Type is for your own notes. It does not change the quantities.
Six inches is the standard. Go wider on slopes and anywhere the fabric will be walked on before the mulch goes down.
Pinning
Edges and seams always. The open field is optional.
Cost, optional
Leave the box size blank to price pins individually.
Common questions
How much should landscape fabric overlap at the seams?
Six inches is the working standard for a flat bed. Take it to eight or twelve on a slope, on windy sites, and anywhere you will be walking on the fabric before the mulch or gravel goes down, because a seam that shifts by an inch or two is exactly where weeds find their way up. Overlap costs material: at a 6 in overlap a 4 ft roll only covers 3 ft 6 in of ground, which is why the strip count here is usually higher than people expect.
How many staples per roll of landscape fabric do I need?
There is no fixed number per roll, because it depends on the shape of the bed rather than the length of fabric. A long thin border has far more edge per square foot than a square bed of the same area. As a rough sense check, a 20 by 10 ft bed pinned at 15 in with 4 ft fabric comes to roughly 90 pins once seams and spares are counted. Work it out from your own dimensions rather than buying one box and hoping.
Should I pin the middle of the fabric or just the edges and seams?
Edges and seams are essential. The open field is a judgement call. Under mulch on flat ground the weight of the mulch holds it and you can skip it. Under gravel, on any slope, or on an exposed windy site, a 24 by 24 in grid across the middle stops the fabric rucking up into ridges under the surface. Use 6 in pins in ordinary soil and 8 to 10 in in loose, sandy or freshly turned ground.
Fabric goes down first, mulch goes on top
Work out the covering that goes over the barrier in the same sitting, so you buy the fabric, the pins and the mulch in one trip rather than three.