A stump under a deck or porch can be ground out once a grinder can reach it, which usually means the stump sits near an open side and the boards or skirting over it come off, or a section of the structure is taken down first. If none of that is practical the stump can be cut low and left, but it is wood in the soil right beside the house, so it deserves a proper plan.
How a stump ends up under the boards
There are three usual stories. The deck was built around a tree, with a hole cut for the trunk, and the tree later died or got too big. The tree was taken down and the deck or porch went over the stump because nobody wanted to deal with it. Or a small tree was cut flush during construction and forgotten until it started sprouting through the gaps or growing mushrooms under the steps. Each one needs a different approach, because what matters is how far the stump is from an open edge and how much room there is between the ground and the framing above it.
Measure the room the machine needs
A grinder works by sweeping a toothed wheel across the stump and lowering it a little with each pass. That needs room beside the stump for the machine and room above it for the wheel to rise and swing. A low deck almost never gives that from underneath. Before you ask for a quote, measure the height from the ground to the underside of the joists, the distance from the nearest open edge to the stump, and the width of the cut face. Photograph the posts and footings near it, any lattice or skirting, and the steps. Those few numbers settle most of the plan before anyone arrives.
Option one: open the boards over a stump near the edge
Lifting boards turns many deck stumps from impossible into ordinary, but only where the machine can sit at ground level beside the deck. With the boards over and around the stump taken up, the wheel gets the headroom to rise and sweep while the machine stays outside the frame. Screwed boards come up and go back with little trouble. Nailed boards often split, so have a few spares. If a joist runs right over the stump, a carpenter can tell you whether a short length can be cut out and headed off safely. Board and joist work is for the owner or a carpenter, done before the grinding day.
Option two: work in from an open side
A stump near the edge of a ground-level porch or a low platform can sometimes be reached from the side once the skirting or lattice comes off. The machine sits outside the footprint of the structure and the wheel reaches in. Whether that works depends on how far in the stump sits and on the posts in the way, which is why the photos matter. This is the kind of job tight access stump grinding is about: getting the wheel onto a stump that a truck-mounted machine could never reach, without taking more apart than you have to.
Option three: take the deck down
Sometimes the stump is the push an old deck needed. If the boards are soft, the posts are rotting at the base and the framing was not built to current practice, taking it down clears the stump, the rot and the trip hazard in one go. Decks are on the list of structures demolition covers, and the stump can be ground once the framing is gone. If you are weighing that up, our deck removal guide walks through what is involved. The ground under a removed deck is usually bare and uneven, so plan the grading and seed at the same time.
Next to the house: the termite question
NC State Extension's advice on preventing termites in existing homes is never to dig soil within 12 inches of the house, because that band is the area treated for termites, and digging it up gives them a way past the treatment. Clemson Extension's termite fact sheet lists removing wood debris in or near the structure as part of control. A stump under a porch can sit inside that band. If it does, call the company that holds your termite contract before anything is ground, and ask how they want the work handled. Grindings from under a porch should be hauled off, not heaped against the foundation. See do stumps attract termites.
Posts, footings and lines in the dark
Under decks is where people run things they do not want to see. Expect concrete footings beside the stump, and sometimes a post set right against its roots. Look for wiring to a hot tub or deck lights, a gas line to a grill or heater, irrigation, downspout drains and dryer or crawlspace vents. SC811 lists building decks among the projects that need a locate request, and its advice is that the property owner is responsible for identifying private lines, which 811 does not mark. Mark anything you know about and say where you are unsure.
Common Questions
Can a stump under a deck be ground without taking the deck apart?
Only if it sits close to an open side, so the machine can stay outside the frame and the wheel can reach in. Even then, a few boards over the stump usually come up to give the wheel headroom. A stump deep under a low deck generally means taking that section apart.
Is a rotting stump under my porch a termite risk?
It is wood in contact with soil next to your house, which is what termite advice warns about. Clemson Extension lists removing wood debris near the structure as part of termite control. Call your termite company before anyone digs within 12 inches of the house, since NC State says that band is the treated zone.
Can the deck boards go back down after the stump is ground?
Usually, yes. Screwed boards lift and refit easily. Nailed boards may split, so keep spares. Once the stump is ground below grade and the hole is filled and settled, the framing above is untouched and the boards go back as they were.
What to Do Next
Send photos of the stump, the deck from the nearest open side and the way in from the street, plus your town. Jordan will tell you how much needs opening up. Call (828) 574-4474 if it is easier to talk it through.