Observe before you act: signs of a conflict
Before lifting a slab or pruning a root, it pays to observe. Paving that begins to sag at one particular point, a joint opening in line with a tree, or a patch of soil showing between tiles usually points to activity from shallow roots. An irregular crack running in several directions, by contrast, tends to say more about the base settling or runoff than about roots.
Observation should be repeated at different times of year. In autumn, after the first rains, it is easier to see where water pools and which areas drain quickly. In a coastal garden, with often sandy soils and mild temperatures, root growth can continue longer than inland, where cold slows it sooner. That detail changes the review calendar: on the coast it is unwise to wait for midwinter to spot lifting.
It also helps to look at the canopy. A tree leaning towards the paving, with low branches brushing against people, may be seeking light and space. That observation guides the decision: sometimes the problem is not the root but where the tree was originally planted.
- Make a simple sketch of the garden with trees, inspection chambers and paving joints; mark the areas that pool water or lift.
- Check whether the crack runs in a straight line towards a tree or appears well away from any planting.
Choosing species according to proximity to paving
Not all roots behave the same way. Fast-growing, large species tend to develop extensive root systems that seek water and oxygen beyond the canopy. Compact shrubs, perennials and low-growing aromatic plants produce more contained systems, though they still need soil volume. The practical decision is to leave more distance than the canopy diameter suggests, because roots usually spread beyond the leaf projection.
On narrow terraces and paths, it is worth thinking about raised beds or continuous planting strips, with enough soil and drainage. A common mistake is planting a shade tree in a tree pit of half a square metre and trusting that pruning above ground will control the root; it does not. Another mistake is surrounding the trunk with concrete or paving right up to the collar, which reduces the exchange of air and water.
In Sotogrande and much of the Costa del Sol, supplementary summer watering can concentrate roots near damp areas, often beside paving and inspection chambers. In autumn, therefore, it is worth reviewing irrigation points and correcting those that send water towards the base of walls or slabs. Adjusting irrigation is more effective than cutting roots afterwards.
- Leave a strip of unpaved soil around the trunk, at least the size of the expected mature canopy, not the current canopy.
- If space is limited, choose shrubs or seasonal plants rather than large trees.
Autumn watering and its effect on roots
In autumn, watering should adapt to falling temperatures and rainfall. On the coast, a warm October may still call for moderate watering; inland, cool nights reduce demand. The typical mistake is to keep the summer programme out of habit, which waterlogs the soil beside paving and encourages shallow roots. Another mistake is to cut watering abruptly after the first rain, when the deeper soil is still dry.
The key is to check moisture a hand's depth down, not just at the surface. If the soil under a slab stays damp while the rest of the garden is dry, it may indicate a leak or poor drainage. In that case, it is worth checking before planting or adding new slabs. Compacted soil under paving retains water and suffocates roots; the answer is not to water more but to improve drainage.
- Water less often and more deeply in autumn, and stop if rain has soaked the soil.
- Check inspection chambers and grates before heavy rain; a blocked grate sends water towards the base of the paving.
Tree pits, joints and drainage: details that prevent problems
The tree pit is the interface between tree and paving. A pit that is too small forces roots to seek space under the slabs. One that is too deep can collect water and rot the collar. The practical approach is to enlarge it gradually as the canopy grows, keep it level or slightly raised, and avoid filling it with fine gravel that compacts. In autumn, it is a good time to remove leaves and sediment and check that water infiltrates.
Joints between slabs matter too. Open joints allow some exchange of air and water but let roots and weeds in. Sealed joints keep weeds out but concentrate runoff. There is no single solution: in walkways, sealing and checking is sensible; in planted areas, leaving joints open and controlling vegetation works better.
For garden work in Sotogrande, it is worth coordinating planting with the paving works schedule. Planting after the slabs are installed rather than before avoids damage during compaction. If the paving already exists, autumn allows small shrubs to be planted and drainage to be reviewed before spring.
- Enlarge the tree pit gradually and keep the tree collar above the level where water pools.
- Do not use compacted fine gravel as the only tree pit fill; leave a thick, airy layer of mulch.
Common mistakes and how to correct them
One of the most common mistakes is cutting thick roots to save a slab. That radical pruning weakens the tree and can make it unstable. If a root is lifting the paving, it is usually wiser to adapt the paving, create a gravel strip or replace the species than to insist on cutting. Another mistake is adding soil over the paving to hide shallow roots: that reduces aeration and does not solve the cause.
It is also common to seal more surface than necessary, leaving the garden without areas where water can infiltrate. In autumn, with rain more likely, this leads to puddles and runoff towards foundations. A practical correction is to restore a permeable strip along the edges of the paving or install a drainage channel.
Finally, not every lift should be read as a root problem. Sometimes the sand base or support has been poorly compacted. Observing, checking moisture and reviewing the direction of cracks allows a sound decision before intervening.
- Before cutting a root, consult a professional to assess the tree's stability risk.
- If the paving lifts, record its progress with photos over several weeks to distinguish root, settling or drainage.