Most people ask the wrong question when they ring us about a stump. They ask how much it costs to grind. The question that actually decides the job is much simpler: what is going on top of that ground afterwards?
Grass and a flower bed? Grinding is almost always the right answer, and it is quicker and cheaper. A car park, a slab, a footing or a hard standing? Grinding on its own will leave you with a problem you cannot see until the surface starts to sink.
This guide walks through the difference by end use, so you can specify the job properly before anyone turns up with a machine. If you are still weighing up whether to do it in house at all, our guide on commercial stump removal vs DIY covers the safety and cost side, and this article picks up where that one stops.
What grinding actually removes
A stump grinder is a wheel with hardened teeth on it. The wheel spins fast and sweeps side to side, chipping the wood away a few millimetres at a time. It does not pull anything out of the ground.
On a normal commercial job, our stump grinding services take the stump down to somewhere between 150mm and 300mm below the finished ground level. That is deep enough that you can put topsoil over it and never know the tree was there. A typical 300mm to 500mm stump takes between half an hour and an hour.
What grinding does not do is remove the root plate. The main structural roots, the ones that spread out sideways and hold the tree up, stay exactly where they are. So do the smaller roots running out from them. They are still wood, and wood in the ground does one thing over time. It rots.
What full excavation removes
Full excavation is a different job with a different machine. An excavator digs around and under the stump, cuts or tears the main roots, and lifts the whole root plate out in one piece or in sections.
Depth depends entirely on the tree. A young ornamental might come out of a hole 600mm deep. A mature oak or poplar can need 1.2 metres or more, and a hole several metres across. You end up with a large void, a large pile of soil and timber, and a site that needs backfilling and compacting before anything can be built on it.
It costs more. It takes longer. It makes far more mess. And on some jobs it is the only thing that works.
The real difference: what rots, and what happens when it does
Here is the part that catches developers out.
When you grind a stump and leave the root plate in the ground, that timber decays over the next five to fifteen years, depending on the species and how wet the ground is. As it decays it loses volume. The soil above it drops into the space.
Under turf, nobody notices. You get a slight dip that gets topped up during normal grounds maintenance, and that is the end of it.
Under tarmac, a concrete slab, block paving or a strip footing, it is a very different story. Voids form under a rigid surface that cannot flex. You get cracking, dishing and settlement, usually in a patch that matches the old root spread almost exactly. The repair costs many times what the excavation would have cost in the first place, and it happens after handover, when it is your name on it.
This is why stump removal before construction is a groundworks decision, not a landscaping one. If you are preparing ground for building, our groundworks team treats the root plate the same way as any other soft spot in a formation level. It comes out.
Decision matrix: choose by end use
This is the table to send to whoever is writing the specification.
| End use of the ground | Grind or excavate | Depth needed | Why |
|---|---|---|---|
| Turf, lawn or amenity grass | Grind | 150mm to 250mm below finished level | Enough soil depth for grass roots. Slow settlement is harmless and easy to top up |
| Planted bed or shrub border | Grind | 250mm to 300mm below finished level | Beds need more rooting depth than grass. Remove chip from the planting zone so it does not lock up nitrogen |
| Car park, access road or hard standing | Excavate | Full root plate out, below formation level | A bound or rigid surface cannot bridge a void. Settlement shows as cracking and ponding |
| Building footprint or foundations | Excavate | Full root plate out, plus any roots crossing the footing line | Organic material in a bearing layer is a defect. Most engineers and building control will not accept it |
| Fence line, gate post or barrier | Excavate locally | Enough to get a clean post hole and 500mm around it | A post set into rotting timber works loose. Cheaper to dig out the short section than to reset posts twice |
| Ground with a known honey fungus problem | Excavate | All woody material out, roots included | Leaving infected wood keeps the fungus fed. See the section below |
If a single site has several of these, treat each area separately. It is normal for us to grind twenty stumps across the landscaped edges of a site and fully excavate the four that sit inside the hard standing areas or under the new building line. You only pay for excavation where the end use demands it.
Arisings: how much material, and where does it go
Grinding turns a stump into chips, and chips take up more room than solid wood. Expect roughly two to three times the original stump volume once it is broken up. A big stump can easily produce a couple of cubic metres of material.
You have three options.
Backfill the hole with it. Fine under grass on a low-key site, and it costs nothing. It will settle over the first year or two and need topping up once.
Reuse it as mulch. Fresh grinding chip contains soil, grit and sometimes bits of stone, so it is not the tidy bark mulch you would buy in bags. It works perfectly well on informal shrub beds and around established trees. Keep it away from new planting, because fresh wood chip pulls nitrogen out of the soil as it breaks down, and young plants suffer for it.
Take it off site. On construction sites, tidy commercial estates and anywhere the chip cannot be reused, it goes. Our green waste removal service handles this, and every load comes with a waste transfer note showing what was taken and which licensed site it went to. On a development, that paperwork matters as much as the clearance itself.
Full excavation arisings are a bigger problem. You get soil mixed with large timber, and it cannot go back in as backfill. Budget for it to leave site.
Backfill: clean subsoil or type 1
Once the root plate is out, you have a hole. What goes back in depends, again, on the end use.
Under soft landscaping, clean subsoil backfilled in layers and compacted, with 150mm to 300mm of topsoil on top, is fine.
Under a hard surface or a footing, you need MOT type 1 or a similar granular fill, placed in layers of around 150mm to 225mm and compacted properly with a roller or a whacker plate. Tipping it all in at once and running the machine over the top does not count as compaction, and it will settle.
Two rules worth writing into any specification. First, no timber, chip or turf goes back into a hole that will carry a load. Second, the backfill should match or beat the bearing capacity of the ground around it, so you do not create a soft patch or a hard patch that behaves differently to everything next to it.
Honey fungus: why leaving wood in the ground can spread a problem
Honey fungus, or armillaria, lives on dead and dying woody material and spreads through soil using black bootlace-like strands called rhizomorphs. Those strands travel roughly a metre a year and can reach plants up to 30 metres from the source. The Royal Horticultural Society’s guidance on honey fungus is clear that the only effective remedy is to dig out and destroy all the infected root and stump material, because that removes the food source the strands depend on.
In practice, that means if you have lost a tree to honey fungus, or you have several dying trees in one area, grinding is not enough. The root plate is the food supply. On a site where you are about to spend money on new planting, excavation is the cheaper option once you count the replacements you would otherwise be buying twice.
Root suckering: some species will not give up
Grinding removes the growing points at the base of the stump, so most trees stop there. A few species send up new shoots from the roots themselves, sometimes several metres away from where the tree stood.
The usual culprits are poplar, cherry, aspen, lime, elm and false acacia. On these, the shoots appear the following spring in lawns, beds and pavement joints, and they keep coming for years.
If a suckering species is going into an area that will be turf or planting, either plan for excavation, or accept that you are signing up to a few seasons of treating the regrowth as part of routine maintenance. It is worth deciding which at the quotation stage rather than being surprised in May.
Access and machine size on tight sites
The specification is only half the job. The other half is whether the machine can get to the stump.
Narrow-access grinders will go through a standard gateway of around 750mm and can work in courtyards, behind buildings and inside fenced compounds. They are slower on big stumps, but they get there.
Larger tracked grinders clear a big stump far faster, but they need proper access, room to turn, and ground that will take the weight.
Full excavation needs more again: an excavator, room for the spoil, and a route out for a grab lorry or tipper. On live sites, that often means phasing the work or doing it out of hours.
Other things that change the price on a real site: buried services near the stump, which need a scan and hand digging around them; retaining walls or building foundations within a metre or so, which limit how close an excavator can dig; and made ground or old hardcore, which slows everything down and wears out teeth. On larger jobs this is usually folded into a wider commercial site clearance package, so the stumps, vegetation and waste are all dealt with in one visit rather than three.
Quick comparison
| Grinding | Full excavation | |
|---|---|---|
| Typical depth | 150mm to 300mm below ground | Whole root plate, often 600mm to 1.2m plus |
| Time for one large stump | 30 to 60 minutes | Half a day or more |
| Ground disturbance | Very low | High, large open hole |
| Arisings | Wood chip, often reusable | Soil and timber, needs removing |
| Backfill needed | Usually none, or topsoil | Clean subsoil or type 1, compacted in layers |
| Suitable under load-bearing surfaces | No | Yes |
| Relative cost | Lower | Higher |
| Deals with honey fungus | No | Yes |
| Stops root suckering | Usually, but not on poplar and cherry | Yes |
Get the end use agreed before you get a price
Almost every stump dispute we see comes from the same gap. Someone priced the job as grinding, and someone else later drew a car park over the top of it.
So before you ask for a quote, mark up a plan showing what each area will become. Turf, beds, parking, building, fence line. From that, the method and the depth follow on their own, and the price you get back is one you can rely on.
We handle stump removal across Essex, Suffolk, Norfolk, Cambridgeshire and Hertfordshire, for developers, facilities managers, estates and local authorities. Get in touch, and we will walk the site, count the stumps, check access and give you a written quote that says which ones we grind and which ones come out completely.
