Every complaint about paving eventually becomes a complaint about water. It puddles in the same corner, the slabs by the back door turn green every winter, or the ground beside the house never dries out. The paving is rarely at fault; where it was told to send the water is.
JV Handyman & Garden Services lays and repairs paving across Edinburgh, and this is the part of the job that gets decided with a level and a length of string before anything is bought.
Falls: small, consistent and always away from the building
Paving is never laid flat. It is laid with a deliberate, gentle gradient, commonly in the region of one in eighty, which is enough to move water off the surface and slight enough that furniture still sits level and nobody notices walking on it. Laid truly flat, surface tension and the smallest settlement will hold water in patches.
The direction is not negotiable: away from the house. A terrace that falls back toward a wall delivers rain to the base of that wall in quantity, and paving that finishes above the damp course lets water bridge it. Finished level below the damp course, with a clear fall away from the building, is the arrangement that keeps a wall dry.
- A gentle, consistent fall beats a flat surface every time.
- Always fall away from the building, never toward it.
- Keep the finished paving clearly below the damp course.
Where the water is supposed to end up
Shedding water off the paving only helps if the receiving ground can take it. A lawn or planted bed at the low edge will absorb a surprising amount; compacted ground or a neighbour's boundary will not, and pushing water onto adjoining land is how a paving job becomes a dispute.
Where there is no natural somewhere, the answer is built: a channel drain across the low edge or the head of a slope, connected to a soakaway sized for the area it serves and sited well away from foundations. On tight sites the better answer is often to stop making runoff at all, by using a permeable build-up so rain goes down through the surface into the stone below.
- Discharge into planting or lawn where the ground can take it.
- A channel drain needs somewhere to go; a soakaway needs room and depth.
- Never drain a new surface onto a neighbouring property.
Front gardens, runoff and permission
Paving over a front garden is the one case where drainage is a permissions question as well as a practical one. Since 2008, replacing a front garden with an impermeable surface over about five square metres has needed planning permission unless the water is drained to a permeable area within the property, which is why permeable paving, gravel and resin-bound surfaces became common.
There is a practical reason as well as a regulatory one. Sealed front gardens send everything to the road at once, which is exactly what overloads drains in a downpour. A permeable build-up, with clean angular stone that holds water in its voids while it soaks away, handles heavy rain quietly and does not need a drain to be dug into the middle of a small frontage.
Repairing a surface that already puddles
A localised dip is usually a sub-base failure rather than a slab problem, so the fix is to lift the affected slabs, correct and recompact the base, and relay. Simply lifting and rebedding on more mortar buys a season or two and leaves the original cause in place.
Green, slippery paving is the visible symptom of water sitting too long, and cleaning it is a treatment rather than a cure. JV Handyman & Garden Services will usually pressure wash and repoint at the same time as correcting the fall, because a clean surface that still holds water is green again by the following winter.
- Lift, correct the base and relay; do not just rebed the slab.
- Repoint open joints, because they let water into the bed.
- Fix the fall, or the cleaning is an annual chore forever.
Related pages
Questions customers ask
How much fall does a patio need?
A gentle gradient of roughly one in eighty is a common working figure: enough to shed water reliably, subtle enough that the surface still feels level underfoot and furniture sits properly.
Do I need permission to pave my front garden?
If more than about five square metres is being made impermeable and the water is not drained to a permeable area within your own property, permission is generally required. Permeable surfaces and drainage to a border are the usual ways round it.
Why does my patio keep going green?
It stays wet for too long. That is usually a fall or drainage issue rather than dirt, so cleaning helps for a season while correcting the levels or adding drainage solves it.
Set the fall first, decide where the water lands before choosing a slab, use a permeable build-up where a front garden makes runoff a problem, and fix the base rather than the symptom when an old surface puddles.
JV Handyman & Garden Services covers Edinburgh for paving, pointing and repairs. The contact page takes a description and rough measurements.
