Guide · For the trade
Porch rug and sunroom rugs: specifying for sun, weather and a floor that sweats
A porch rug is a UV-stabilized polypropylene or solution-dyed polyester flatweave or low machine-woven pile, sized by the 70 percent rule (the rug covers about 70 percent of the floor, with 18 inches of decking at the edges) or, at the front door, a 3 by 5 or 4 by 6 foot rug under a coir doormat. Sunroom rugs follow the same fiber rule in a three-season room and relax it in a conditioned four-season room, where a wool rug on a felt-and-rubber pad is fine out of the direct sun or behind UV-filmed glass. The variable in both rooms is light: a south or west glass wall delivers most of the ultraviolet of an open porch, and the fade on a dyed wool is measured in months.
This guide is for the designer specifying a front porch, a back porch or a glassed-in sunroom for a client: the four exposures and the spec for each, porch sizes, the sunroom floor, fade, pads and seasonal care. Covered patios, decks and screened porches are in the patio rugs guide; this page picks up the front porch and the room with glass.
Four exposures, four specs
| Space | Exposure | Fiber and construction | Pad |
|---|---|---|---|
| Open front porch | Rain blows in, full sun part of the day, street grit | Polypropylene flatweave, reversible, under 1/4 inch | None, or a thin drainage pad |
| Covered back porch | Shaded, damp mornings, leaf litter | Polypropylene or polyester, flatweave or low machine woven to 3/8 inch | Open-weave outdoor pad, 1/8 inch |
| Three-season sunroom | Glass on two or three sides, unheated, humidity swings | Solution-dyed polypropylene or polyester; indoor outdoor broadloom cut and bound | Synthetic felt or rubber pad, 1/4 inch |
| Four-season sunroom | Conditioned, direct sun on part of the floor | Any indoor rug away from the sun; wool only with UV film or a north exposure | Felt-and-rubber, 1/4 to 3/8 inch |
The division that matters is conditioned or not. An unheated glass room hits 100 degrees in July and 35 in January and its humidity follows the outdoors; it is an outdoor room with a roof and takes outdoor goods. A conditioned sunroom at 50 percent relative humidity is an indoor room with a light problem.
The front porch: sizes and the doormat question
For a porch 6 to 8 feet deep with two chairs and a table, a 5x8 with its long side along the house wall leaves the walkway clear; a deeper porch with a swing or a sofa takes a 6x9 or an 8x10. At the door, a 3 by 5 or 4 by 6 foot rug centered on the door and extending at least 12 inches beyond the frame each side, with a coir doormat 18 by 30 or 24 by 36 inches layered on top; a flatweave stripe under plain coir is the layered look clients ask for. Keep the rug clear of the door swing and under 1/4 inch so the storm door clears it. Runners come at 27, 32 and 36 inch widths; 32 inches suits a porch 5 to 6 feet deep with chairs against the wall.
Porch rug fiber: what "waterproof" and "heavy duty" mean
Polypropylene absorbs under 0.1 percent of its weight in water, so rain runs off, the rug dries in hours standing on edge, and a hose and a soft brush clean it. It is not waterproof in the sense of keeping water off the floor beneath: a rug left flat on a wood porch after rain holds water against the boards, which is why the porch spec is a reversible flatweave with no pad or a drainage pad, never a rubber-backed mat on wood. "Heavy duty" on a product page means a thicker flatweave or a woven backing; it is not a test. Couristan, Prestige Mills and Stanton carry most of the indoor outdoor broadloom we cut to porch sizes, about 200 styles, 140 of them polypropylene.
Sunroom rugs and the floor that sweats
Most sunrooms sit on a slab or tile over slab, and in a humid week that floor condenses moisture under anything flat on it. The spec is a synthetic rug, or a wool rug on a pad that lets air through, lifted and checked twice a year; the wrong spec is a rubber-backed rug or a solid rubber pad on tile, which traps the condensation and shadows the grout. On a wood floor in a conditioned sunroom the ordinary indoor rules apply, covered in the rug pad for hardwood guide.
Fade: the number to tell the client
Ultraviolet through plain glass is roughly two thirds of what reaches an open porch; low-e glass cuts it further, and a UV film inside the glass cuts it to under 1 percent. A piece-dyed wool rug in a south-facing sunroom with plain glass shows a line where the sun stops within a single summer. Solution-dyed polypropylene and polyester, with the color in the polymer, hold for years in the same spot. For the client who wants wool: specify a UV film or a shade, place the rug out of the direct patch, rotate it twice a year, and choose an undyed or washed palette with less color to lose.
Sizing a sunroom rug
For a 10 by 16 foot sunroom with a sofa and two chairs, an 8x10 under the front legs of all three; for a 12 by 20 room with seating and a dining table, a 6x9 and an 8x10 with 3 feet of floor between them, or one indoor outdoor broadloom rug cut to 10 by 17. The 18 inch rule relaxes to 12 inches because the room is narrow, and the rug never runs to the glass: that strip of floor is the wettest and sunniest in the house.
Seasonal instructions to hand the client
- Porch rugs come in for the winter in snow country, rolled and stored dry; in mild climates they stay out and are hosed and stood on edge after a storm.
- Sunroom rugs are lifted, the floor wiped and the pad checked, in spring and fall, and rotated 180 degrees at the same visits.
- Vacuum both with suction only; a beater bar frays a flatweave edge.
Questions designers ask
Can a porch rug be left out all year?
A polypropylene flatweave can, in a climate without snow, as long as it dries after rain, stood on edge or on a drainage pad. In snow country it is rolled and stored for the winter, because a rug frozen to the decking holds water against the wood for months.
What is the 70 percent rule for rugs?
The rug covers about 70 percent of the floor it serves, leaving a band of floor, usually 18 inches, at the edges. On a porch 8 by 12 feet, that is roughly a 6x9; in a 10 by 16 sunroom, an 8x10. The furniture plan adjusts it.
What are the standard rug sizes for a porch or sunroom?
5x8, 6x9 and 8x10 cover most porches and sunrooms; 9x12 for a large sunroom; 3x5 and 4x6 at a front door; runners at 27, 32 and 36 inches wide. Anything in between is cut from indoor outdoor broadloom and bound in 3 to 5 weeks.
How is a front porch rug cleaned?
Vacuum the grit, hose it flat, scrub spots with a soft brush and a mild detergent, rinse, and stand it on edge until dry on both faces. A polypropylene rug takes this indefinitely; a polyester rug takes it with a lighter hand on the brush.
Can a wool rug go in a sunroom?
In a conditioned four-season sunroom, yes, out of the direct sun or behind UV film, on a felt-and-rubber pad with an open base, rotated twice a year. In an unheated sunroom, no; the humidity swings and slab moisture are a basement's, and the spec is synthetic.
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