The Slope You Are Aiming For
The working rule is simple. The ground should drop about six inches over the first ten feet measured straight out from the foundation wall. That is roughly a five percent slope, and it is a minimum rather than a ceiling. If your yard beyond that ten foot band can absorb or carry the water, more fall is fine and often better.
The reason this number gets repeated everywhere is that water sitting at the wall has nowhere to go but in. It works into block joints, hairline cracks, and window wells, and it stays there long enough to matter. Soil that slopes back toward the house is worse than flat soil, because it takes every roof drip and every hose run and concentrates it against the one spot you least want it. Flat grade is a slow problem. Negative grade is an active one.
The first ten feet do most of the work. Past that, the yard does not need a measured slope, it just needs to keep moving water away from the house instead of back toward it. A gentle fall across the lawn, a shallow swale, or simply a yard that drops off toward the street is enough.
Checking what you have now takes two stakes and a string. Drive one stake at the foundation wall and a second stake ten feet straight out. Run a string between them and level it with a line level or a torpedo level laid on the string. Then measure straight down from the string to the soil at the far stake. That measurement is your drop. Anything under six inches means you are short, and anything at or near zero means water is sitting in that band after every storm.
On older houses, losing the grade is normal and it happens quietly. Backfill placed during construction keeps settling for the first several years, so the ground right at the wall drops. Then the beds get edged, mulched, and topped up again every spring, which raises the soil line near the house while the far edge of the bed stays exactly where it was. Twenty years of good intentions can produce a bed that tips back toward the basement.
Why the Wedge, Not the Rectangle, Sets Your Order
Almost every soil calculator assumes you are laying a flat slab of material at one uniform depth. That is the right model for topdressing a lawn or filling a raised bed. It is the wrong model for grading, and it is the single biggest reason people over order or under order dirt for this job.
What you are actually building is a wedge. It is deepest right at the foundation, where you need the new high point, and it tapers to nothing out where your new surface meets the existing grade. Picture a long triangular ramp running along the wall.
The shortcut is easy to remember. Average depth equals half the drop you are adding. If you need to create six inches of new fall across a ten foot band, the average depth of material across that band is three inches. Deep at the wall, zero at the tip, three on average.
That one line of arithmetic prevents a mistake in both directions. Order for six inches across the whole band and you buy nearly double what the job takes, which means a leftover pile you have to find a home for. Order for the thin tapered edge and you run out before you get anywhere near the wall, which is exactly where the depth counts.
There is one case where the wedge shortcut is not the whole story. If you also have a distinct low spot, a birdbath area that holds water after rain, or a settled trench over an old utility run, that volume is separate. Measure it, estimate it as its own rough block of material, and add it on top of the wedge number. Filling a two foot wide, fifteen foot long, four inch deep depression is a real volume, and it will eat into a wedge order if you do not account for it.
Running the Cubic Yard Math
The Formula
Length in feet times width in feet times average depth in feet, divided by 27, gives cubic yards. The 27 is there because a cubic yard is three feet by three feet by three feet.
The only piece that trips people up is the depth, because you measure it in inches and the formula wants feet. Divide inches by 12. Three inches is 0.25 feet. Four inches is 0.333 feet. Six inches is 0.5 feet.
A Worked Example
Say you have a 30 foot by 40 foot house. The perimeter is 30 plus 40 plus 30 plus 40, which is 140 feet. You want to regrade a ten foot band all the way around, building six inches of new fall, so your average depth is three inches, or 0.25 feet.
That is 140 times 10 times 0.25, which equals 350 cubic feet. Divide 350 by 27 and you get about 13 cubic yards.
Most homeowners do not do the whole perimeter. Usually one or two sides are the problem and the rest drains fine. For a single 40 foot wall with the same ten foot band at three inches average depth, the math is 40 times 10 times 0.25, which is 100 cubic feet. Divide by 27 and you get about 3.7 cubic yards. Call it four.
You can cross check either result against coverage. One cubic yard of topsoil covers about 108 square feet at three inches deep. That 40 foot wall band is 400 square feet, and 400 divided by 108 is about 3.7. The two methods agree, which is a good sign you did not misplace a decimal.
Sanity Checks Before You Order
Typical install depth for topsoil is three to six inches, so a grading wedge with a three to four inch average sits comfortably in normal range. If your math is telling you that you need an average depth well past six inches at the wall, stop and read the clearance section below before you order anything.
Plan for weight, not just volume. Topsoil runs about 1.2 tons per cubic yard, so that four yard single wall job is roughly 4.8 tons and the 13 yard full perimeter job is about 15.6 tons. That matters for where the pile goes, what your driveway can take, and whether you are realistically moving it with a wheelbarrow or need a friend with a compact tractor. Screened soil sits in the low price band, which is why bulk delivery wins over bagged for anything past a wheelbarrow or two.
Add a small cushion. Soil settles as it takes on water and gets compacted underfoot, and the thin tip of a wedge is very easy to under measure. Rounding up by a yard or so costs little compared to paying for a second delivery because you came up one wheelbarrow short. If you would rather not do the arithmetic by hand, run your numbers through a soil calculator and use the wedge trick to set the depth field.
Fill Dirt Under, Screened Topsoil On Top
Two different materials do two different jobs here, and using one for both is where grading projects go sideways.
Fill dirt builds bulk and holds a shape. It is heavier in clay and mineral content, it compacts, and it stays where you tamp it. It is not a growing medium, and seed put directly on it struggles.
Screened topsoil is locally stripped and screened native soil, so color and texture vary by region. It gives you a surface grass and plants will actually accept. What it will not do is hold a tall shape reliably. A foot of loose, organic rich soil stacked at the wall stays spongy, holds moisture right against the foundation, and keeps settling for a year or two after you walk away. That is how a fresh grade turns back into a negative grade.
So for deep corrections, layer it. Build the bulk of the wedge with fill dirt placed and tamped in lifts, then cap it with roughly three to four inches of screened topsoil to carry the seed or sod. Our install note applies directly here. Screened topsoil is a base, not a finished growing medium. For a new lawn area, plan on about four inches over prepared subsoil, raked and lightly rolled.
If the total build up is small, say two or three inches, skip the layering. Screened topsoil alone over a scratched up subsoil surface is fine at that depth.
Two finishing habits matter more than the material choice. First, feather the outer edge of your new soil into the existing grade instead of leaving a lip. A hard seam settles differently from the ground next to it and shows up a year later as a visible trench line across the yard. Second, strip or at least scratch up the old surface before you add anything. New soil spread over compacted, thatch covered ground tends to sit as a separate layer and slide, rather than knitting into what is underneath.
The Clearance Limits That Cap How Much You Can Add
This is the part that stops a lot of grading plans, and it is better to find out now than after the dirt is in the driveway. You do not get unlimited depth at the wall.
Leave a band of foundation visible. A good target is roughly six inches of concrete, block, or stone showing above the finished soil line. Some guidance uses four inches as the floor. Either number makes the same point, which is that the foundation should be visible rather than buried.
Never let soil or mulch touch siding, trim, or any wood. Vinyl, wood, and fiber cement all assume they sit above the dirt line, and none of them are built to be in constant contact with damp soil. Soil packed against siding also hands termites and carpenter ants a hidden bridge straight past the foundation, where nothing you can see from outside will tell you it is happening.
Brick veneer homes need one extra check. Look along the bottom course for small open gaps in the mortar joints. Those are weep holes, and they drain the cavity behind the brick. Burying them traps water inside the wall assembly.
Mulch counts toward the soil line. A bed that gets two inches of fresh mulch every spring is climbing whether you notice it or not, and after several years that mulch can be the reason your clearance disappeared. When you set your target line, set it for finished mulch surface, not bare soil.
So what do you do when the clearance math and the slope math fight each other. If holding six inches of exposed foundation means you cannot fit six inches of fall into ten feet, soil alone will not fix it. Reasonable options are a shallow swale further out in the yard to intercept and redirect water, downspout extensions that discharge well past the grade change, or a drain line that carries water to a lower point on the property. Some houses were simply built with the foundation set too low relative to the yard, which leaves no room to grade at all. That is worth diagnosing before you order material, not after.
Placing, Compacting, and Finishing the Grade
Before any material moves, set your reference. Mark the target soil line on the foundation with chalk or tape and work down and out from that mark. It is much easier to hold a grade you can see than one you are carrying in your head.
Work in lifts rather than dumping the whole wedge at once. Six to eight inch lifts of fill dirt, tamped after each one, hold their shape. Compaction is what keeps the grade from quietly undoing itself. Uncompacted fill settles over a season or two and you are back to negative grade with nothing to show for the work. A hand tamper is plenty for a narrow bed. A rented plate compactor is much faster on long runs.
Do not compact the topsoil cap the same way. Rake it to shape, then roll it lightly so seed has soil contact without sealing the surface into a hard crust.
Check the slope with the string line and level as you go rather than after the pile is gone. Pull the string, look at the gap, adjust, and move on. Fixing a grade that is two inches shy is trivial with material still on hand and annoying without.
Watch the hardscape transitions. Keep new soil below the surface of patios, walkways, and driveways so water sheds off them and away, instead of pooling against the edge or running back under the slab.
Downspouts finish the job. A perfectly built grade still fails if a downspout dumps an entire roof of water right at the wall. Extend the discharge out past the ten foot band, onto ground that keeps moving it away.
Then get cover on it fast. Bare soil on a fresh slope moves in the first hard rain, and losing the tip of your wedge is losing the part you measured most carefully. Seed and straw, an erosion blanket, or sod all work. Settle the new soil with light, repeated watering rather than one heavy soaking, which tends to wash the wedge apart before roots have anything to hold.
How We Started
We started Mulch Mound because we got tired of the hassle that came with buying landscaping materials. The options were either loading bags into your car at a garden center or calling around to local suppliers, trying to figure out pricing, minimums, and delivery schedules. Neither option felt convenient or transparent.
Three of us – Alec, Mo, and Tyler – decided there had to be a better way. Alec and Tyler got their start back in 2013 running a landscaping business during college, moving mulch and mowing lawns to pay tuition. That experience taught them how frustrating it was to source materials, and years later, that frustration turned into Mulch Mound.
We focus on making it simple to get mulch, stone, and soil delivered directly to your home. Order online, pick your delivery date, and we handle the rest. No loading bags. No calling multiple suppliers. No wondering if you bought enough or paid a fair price.
We work with quality local suppliers in the areas we serve and aim to be straightforward about what we offer and what it costs. Landscaping is hard work. Buying the materials for it shouldn't be.
Frequently asked questions
Do I need to compact the soil when building up grade around a foundation?
Yes for the fill portion, no for the topsoil cap. Fill dirt should be tamped in lifts as you build. The topsoil on top just gets raked and lightly rolled.
A quick field test once the grade is shaped. Walk the finished surface in normal shoes and look at your footprints. Light impressions are fine. If your heel sinks noticeably more than a fingertip deep, the fill under the cap needs another pass with the tamper before you seed.
How much foundation should stay exposed above the finished soil line?
Rather than measuring up from the dirt, look at the house first and work down. Find where the siding, trim, or brick begins, and your finished soil line needs to sit clearly below that point with a visible band of foundation in between. That is how an inspector or a home inspector reads it, and it is why a tape measure alone can mislead you. A wall with a tall exposed foundation gives you room to work. A wall where siding starts an inch above the mulch gives you none.
Can I pile soil up against my siding to fix the slope?
No, and the failure pattern is predictable. The bottom course stays damp and starts to rot or delaminate. Insects use the soil contact as a covered entry that you cannot see from outside. Moisture wicks into the wall and shows up inside as staining or soft trim.
The repair is worse than the original grading problem, because fixing it usually means pulling siding off to get at the framing and sheathing underneath. If the only way to hit your slope target is to bury siding, the answer is drainage, not dirt.
How wide should the regraded band be?
Ten feet is the benchmark, but real yards rarely cooperate. A fence line, a property line, a walkway, or a neighbor's grade often sets your actual width. A steeper drop over a shorter run is acceptable as long as the water has somewhere to go once it gets there. Six inches of fall in six feet sheds water fine. What matters is that you are not just moving the puddle from the wall to a spot four feet out.
Can I do this with bagged soil?
You can, but you probably do not want to. Even a single wall regrade comes out to several cubic yards, which is many, many bags to buy, haul, open, and dispose of. Bulk delivery is noticeably cheaper per yard at this scale, and it saves you the plastic pile. Bags make sense for topping off a low spot or patching a seam after the main work is done.