A roll of polyethylene (poly):

Comes in 500 sq.ft. or 1500 sq.ft. rolls, and in varying thicknesses. Poly labelled "lightweight" is about 1 mil thick, and a useful weight for general covering of furniture, etc.

A four foot roll is double-folded and will unfold to 8 1/2 ft. width.
A 2-foot roll (actually 34") will unfold to the same width.

Why do I mention this?

Because the narrower roll (of 1 mil) is triple-folded, and will therefore provide 3-mil protection when layed out alongst the wall base without unfolding.

Don't forget that poly is slippery when wet (from water, cooking oil, etc.).
So when wallpapering, overlay your poly with (absorbent) dropsheets to provide good footage and to soak up miner spills.

Comes in various weights (thicknesses). Painter-grade is 'lightweight', which is about 1 mil. Used for draping furnishings, masking off walls, this weight won't withstand much underfoot traffic - it tears readily, snags and rips on hangups. And because small holes and rips are not easily seen, reusing these lengths in other rooms (i.e. re-cycling) won't offer the same level of protection from water, paint spills, etc.

For floors, 2 mil should be the minimum weight.

Professionals will use a heavier grade (4 mil+) but for small jobs, 2 mil is adequate, And it's hard to justify the extra expense for something that will soon share intimate space in some landfill alongside the discarded icons of yesterday.

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