What to put under a deck: rock, gravel, fabric and ground covers

The space under a deck is where good yards go to look bad. Weeds push up between the joists, rain drips through the board gaps and turns the dirt to mud, and sooner or later something furry decides the dark, dry corner by the house is a fine place to raise a family. If you are trying to work out what to put under a deck, the honest answer is that it depends on three things: how high the deck sits, how water moves through that spot, and whether anyone can actually see under there.

This guide walks through the setup that works for most decks (graded ground, landscape fabric, and a few inches of rock), compares the rock options with current 2026 prices, covers the short list of plants that survive in deck shade, and finishes with drainage, critter-proofing, and ways to make the visible edge look intentional instead of accidental.

The layered baseline: grade, fabric, then rock

For most decks, the best material to put under a deck is not one material. It is a three-layer system, installed in this order:

1. Grade the ground first. Rake and slope the soil so water runs away from the house, not toward the foundation. Even a gentle, consistent fall does the job. If water currently pools under the deck, fix that before you cover anything (more on drainage below).
2. Lay landscape fabric. A woven or non-woven geotextile fabric blocks weeds and keeps the rock layer from sinking into the soil, while still letting water drain through. Basic fabric runs about $0.20 to $0.80 per square foot in material depending on grade, and professional installation adds roughly $0.48 to $0.99 per square foot. Overlap seams by 6 to 12 inches and pin it down with landscape staples.
3. Add 2 to 4 inches of rock or gravel. The rock holds the fabric down, sheds the drip line water that comes through the deck boards, keeps mud and splash-back off your framing, and leaves nothing for weeds to root in.

One thing worth saying plainly: use fabric, not plastic sheeting, in most climates. Solid plastic blocks water from soaking into the soil, so runoff either escapes at the edges or sits in stagnant pools under the deck. Trapped moisture under a wood structure is exactly what you are trying to avoid. Permeable fabric lets rain seep through slowly and dry out, which is why deck builders and gravel suppliers consistently recommend it over plastic. The exception is a deck with an engineered drainage system that intentionally captures and routes water; those are designed around impermeable layers, and they are covered later in this guide.

Skip the fabric and you will regret it within two seasons. Gravel laid on bare soil slowly sinks in, weeds come up through the stones, and you end up re-buying rock to top up a bed that keeps swallowing it.

The best rock for under a deck, compared

Any of the first four options below will work over fabric. The differences come down to price, drainage, and how the edge looks where the rock meets the rest of the yard.

Costs are for material only, before delivery ($50 to $150 for most local hauls) and labor. As a rough guide, one ton of rock covers about 70 to 120 square feet at a 2 to 3 inch depth, so material for the gravel options lands near $0.40 to $0.80 per square foot, with river rock running higher.

Washed river rock

Smooth, rounded, and available from about 3/8 inch up to fist-sized stones. River rock drains well, looks finished where the deck edge is visible, and does not break down. At $45 to $130 per ton it is the most expensive of the common choices, which is why many people use it only on the visible border and fill the hidden area behind it with cheaper crushed stone. Sizes in the 1 to 3 inch range stay put better than small stones under a drip line.

Crushed gravel (#57 stone)

The workhorse. #57 stone is crushed rock in the 1/2 to 1 inch range, angular enough to lock together and stay where you spread it. It is what contractors use under decks nobody will ever look at, and it costs $25 to $50 per ton for material. Drainage is excellent. The only real complaint is the plain gray quarry look, which does not matter at all if skirting hides it.

Pea gravel

Small, rounded, about 3/8 inch, in mixed warm tones. Pea gravel is comfortable to walk on and easy to spread, at $30 to $55 per ton. Its weakness is that round stones roll: without a solid border of landscape edging or timber, pea gravel migrates out into the lawn and ends up in your mower. Under a fully skirted deck that movement matters less.

Decomposed granite

Fine granite particles that compact into a firm, walkable surface with a warm tan color. Material costs about $0.30 to $0.70 per square foot, and a ton covers roughly 64 square feet at 3 inches deep. It suits high decks where the space underneath doubles as a patio or storage area. The trade-off is drainage: compacted DG sheds water rather than absorbing it, so it wants a properly sloped base more than loose gravel does.

Rubber mulch

Shredded recycled tires, sold at $6 to $9 per 0.8 cubic foot bag. It never decomposes and will not feed weeds, which sounds ideal. In practice there are three honest problems: it absorbs and radiates heat in sun-exposed areas, it burned faster and more severely than wood mulch in Consumer Reports fire testing, and tire rubber leaches zinc into the soil over time, which several university extensions flag as a reason to keep it away from planted areas. Under a deck near your house, the fire behavior alone is a reasonable dealbreaker.

What about regular wood mulch?

Usually not. Organic mulch holds moisture against your framing and posts, breaks down into planting medium for weeds within a couple of seasons, and gives insects a comfortable habitat right under a wood structure. It is cheap up front ($30 to $60 per cubic yard) and costs you again every year after. Rock costs more once and then stops costing.

Sand and bare soil

Sand looks tempting because it is cheap and easy to rake level, but it fails the two tests that matter under a deck. It holds moisture against the framing, and burrowing animals treat it as an invitation. Rain also ruts and displaces it, so it needs regular regrading. Bare soil is the free option with the same problems plus mud and a steady weed crop. If budget is the constraint, graded soil under landscape fabric with a thinner 2-inch rock layer beats either on every count except day-one cost.

Concrete or pavers, when the space under the deck will be used

A tall walk-out deck can hide genuinely useful square footage: dry storage, a shaded patio, a spot for the grill. If you plan to use the space, a hard floor earns its price. A basic concrete slab typically runs $6 to $12 per square foot installed in 2026, graded away from the house. Pavers over a compacted gravel base give a similar dry, level floor without the permanence of a slab, and you can lift and relevel them if the ground moves. Pair either with an under-deck drainage system (covered below) if you want the space to stay dry in rain, and treat the slab slope with the same care as the grading step above.

Plants under a deck are a conditional yes. Under a low deck (less than about 3 feet of clearance) there is not enough light or rainfall for anything to grow, and rock is the right call. Under a tall deck, where sunlight reaches the outer few feet and rain can angle in, a shade ground cover can soften the edge where hard rock would look stark. Think of it as a lawn alternative for the strip along the drip line, not carpet for the deep dark middle.

The realistic candidates for deep shade:

• Moss: the champion of dark, damp, compacted ground. No mowing, no height, tolerates the deepest shade of anything on this list. It needs consistent moisture, so it suits shaded north sides better than dry climates.
• Sweet woodruff (Galium odoratum): spreads politely in moist shade, 6 to 8 inches tall, with small white spring flowers and a hay-like scent when it dries.
• Dead nettle (Lamium maculatum): silver-marked leaves that visibly brighten a dark space, which is exactly what the shadow line of a deck needs. Handles dry shade better than most.
• Vinca minor (periwinkle): evergreen, tough, and tolerant of nearly full shade. The caveat is real: vinca is classified as invasive in parts of the US because it escapes into woodlands and smothers native plants, according to the North Carolina Extension plant toolbox. Check your state's invasive list first, and skip it if your yard borders natural areas.

Two rules keep this from becoming a maintenance project. Plant only where you can see daylight from under the deck at midday; if you cannot, nothing will photosynthesize there. And remember the deck acts as an umbrella, so anything planted underneath needs hand-watering or a drip line to establish.

Drainage and moisture: fix the water before you decorate

Everything above assumes water leaves the space under your deck. If it does not, solve that first, because no surface material fixes a low spot.

• Grade away from the house. The ground under and around the deck should fall away from the foundation. This is the cheapest fix on this list and the one most often skipped.
• Add a French drain if water collects. A French drain is a gravel-filled trench with a perforated pipe that carries water to a lower discharge point. Shallow exterior runs cost about $10 to $35 per linear foot installed in 2026, with the national range for more involved systems reaching $65 or more. Under a deck, a single run along the uphill side is often enough.
• Consider an under-deck drainage system for elevated decks. These membrane or trough systems catch water between or below the joists and route it to a gutter, turning the area below a second-story deck into genuinely dry space you can furnish. Materials for a system like Trex RainEscape run about $6 to $8 per square foot, and installed costs for drainage plus a finished ceiling typically land between $15 and $40 per square foot, with some pros quoting up to $60 in high-cost markets. Worth it if you want a dry-below patio; overkill for a ground-hugging deck.

Keeping animals out from under the deck

Skunks, raccoons, groundhogs, and neighborhood cats all read an open deck void as free real estate. Skirting alone does not stop the diggers. The fix that actually holds is skirting plus a buried barrier:

1. Staple 1/4 or 1/2 inch galvanized hardware cloth to the deck framing behind the skirting.
2. Trench along the perimeter and bury the mesh at least 12 inches deep, bending the bottom outward into an L shape so a digging animal hits wire and gives up.
3. Do this in fall or late winter if you can. Sealing a den in spring risks trapping babies inside, which becomes a much worse problem.

Hardware cloth costs about $1.50 to $2.25 per square foot, or roughly $40 to $70 for a 25-foot roll. A weekend and a spade cover most decks. The same approach works on the raised platforms around pool decks; if that is your situation, the above ground pool deck ideas post covers those structures in more detail.

Making the underside look finished

Once the ground layer is handled, the visible gap between deck and grade is what separates "nice deck" from "deck on stilts." Three treatments do most of the work:

• Skirting. Wood lattice is the budget classic at roughly $1 to $2 per square foot in materials; vinyl lattice runs about $1.65 to $1.90 per square foot and never needs paint. Installed skirting typically costs $4 to $9 per square foot, and horizontal composite boards sit at the premium end. Leave an access panel; you will need to get under there eventually.
• A defined border. A band of river rock, pavers, or a low hardscaping edge where the under-deck gravel meets the lawn makes the whole thing read as designed. Steel or stone edging also keeps loose rock out of the grass.
• Lighting. A few low-voltage landscape lighting fixtures washing the skirting, or riser lights on the deck stairs, turn the dark band under the railing into a feature at night.

If you want to see these options on your actual deck before buying anything, this is where an AI render earns its keep. Upload a photo of the deck and yard to OutdoorBrite and try AI deck design concepts with different skirting, rock borders, and planting. Comparing lattice against horizontal skirting on your own house takes a minute per concept, which is cheaper than test-fitting materials in real life. For more visual inspiration on dressing up the surrounding area, the under deck landscaping ideas post is a good companion to this one.

Key takeaways

• Default recipe: grade the soil away from the house, lay landscape fabric, top with 2 to 4 inches of rock. This solves weeds, mud, and splash-back in one weekend.
• Pick rock by visibility: cheap #57 crushed stone where skirting hides it, river rock or pea gravel where the edge shows, decomposed granite if the space doubles as usable floor.
• Skip plastic sheeting and wood mulch. One traps water under your framing, the other feeds weeds and bugs.
• Plants only with light: moss, sweet woodruff, and dead nettle handle the shaded fringe of tall decks; nothing grows in the dark middle.
• Critters need wire, not just skirting. Buried L-shaped hardware cloth is the fix that lasts.

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Prices are typical delivered ranges as of August 2026 and vary by region, supplier, and delivery distance. Get two or three local quotes before ordering by the ton.

FAQ

What is the best material to put under a deck?

For most decks, the best setup is graded soil covered with permeable landscape fabric and 2 to 4 inches of gravel or rock. It blocks weeds, drains rain from the board gaps, and keeps mud off your framing. Crushed #57 stone is the value pick for hidden areas; river rock looks better where the edge is visible.

Should I put sand under my deck?

No, sand is one of the weaker choices. It holds moisture against the framing, invites burrowing animals, and ruts and displaces in rain, so it needs regular regrading. If cost is the reason you are considering it, fabric plus a thin 2-inch layer of crushed gravel is only slightly more expensive and solves the problems sand creates.

What is the best rock to put under a deck?

Crushed #57 stone ($25 to $50 per ton) if the space is hidden by skirting, washed river rock ($45 to $130 per ton) if the edge shows, and decomposed granite if you want a firm surface to walk or store things on. All three should go over landscape fabric so they do not sink into the soil.

Should I put plastic or landscape fabric under a deck?

Landscape fabric, in almost every case. Plastic sheeting blocks drainage, so water pools and holds moisture against your posts and joists. Permeable fabric lets rain soak through and dry out while still stopping weeds. The exception is an engineered under-deck drainage system, which uses impermeable membranes on purpose and routes the water to a gutter.

What ground cover grows under a deck?

Only shade specialists, and only where some light reaches: moss for damp, dark ground, sweet woodruff and dead nettle for the partly lit fringe of taller decks. Vinca minor also tolerates deep shade but is invasive in parts of the US, so check your state's list first. Under low decks with no light, use rock instead; nothing grows in full darkness.

How do I keep animals out from under my deck?

Combine skirting with buried 1/4 or 1/2 inch hardware cloth. Trench around the perimeter, bury the mesh at least 12 inches down, and bend the bottom outward in an L shape so digging animals hit wire. Seal it up in fall or late winter to avoid trapping spring litters inside.

Can I just leave dirt under a deck?

You can, but you will be back. Bare dirt grows weeds wherever light sneaks in, turns to mud and splashes your framing in rain, erodes under the drip line, and invites burrowing animals. Fabric plus gravel costs a few hundred dollars for a typical deck and removes all four problems at once.

How much rock do I need under a deck?

One ton covers roughly 70 to 120 square feet at 2 to 3 inches deep, depending on stone size. So a 12 by 16 foot deck (192 square feet) needs about 2 to 3 tons. Order slightly over, since a thin spot in the drip line is where washout starts.

Is rubber mulch good under a deck?

Generally no. It does suppress weeds and never rots, but it retains heat, burned worse than wood mulch in Consumer Reports testing, and leaches zinc into the surrounding soil over time. Next to a wood structure attached to your house, gravel does the same job without the fire concern.