Living With a Permeable Surface Questions Checklist

Ask directly whether this surface forms part of the site drainage, rather than whether it is permeable, and record the answer you receive.

The two questions sound the same and are not; a surface can let water through without being relied on to do so.

What a surface is actually doing can only be established from records or by a qualified drainage professional; appearance settles nothing.

Work out who could answer, whether a developer, a previous owner, a designer, a management company or whoever laid it, and approach each in turn.

The answer usually exists with somebody, and the window in which they are contactable is shorter than owners assume.

Ask whether the store beneath is lined or open to the ground, because the same visible surface does different things depending on that answer.

Whether water is given to the ground or held and passed on is invisible from above and decides what the surface is for.

Ask whether water leaves the surface through any form of restriction or control, where that sits physically, and whether it can be reached.

Where a restriction exists it is a component somebody has to be able to reach, and most owners do not know they have one.

Ask whether anything other than rain falling directly on it is directed onto the surface, such as a roof or an adjoining area.

A surface taking water from elsewhere is doing more work than its area suggests, and that is not visible either.

Write the answers down with the date and who gave them, and keep them with the property paperwork rather than in correspondence.

These answers are the whole of what a future owner will have, and they survive only if somebody deliberately files them.

Note that the construction beneath may be both spreading traffic loading and storing water, and that neither duty is visible from above.

Understanding that both are happening in the same material is what makes the later questions in this checklist make sense.

Ask where water goes when the store beneath is full and rain has not stopped, and whether that route was ever drawn.

Every such arrangement has a condition beyond its assumption, and the route it then takes is a design output rather than luck.

Ask what is expected to stop silt and grit reaching the store, and whether anything has to be cleaned or emptied for that to keep working.

Material that gets into an open store cannot be taken out again, so whatever intercepts it decides how long the arrangement lasts.

Note which parts of the arrangement can never be inspected without excavation, and record that as a limit on anything you can establish yourself.

Knowing what is unobservable prevents an owner from concluding that a surface is fine because nothing looks wrong.

Ask what upkeep the surface was assumed to receive, how often it was expected to happen, and who was supposed to arrange it.

An assumed maintenance regime that nobody was ever told about is the commonest reason these surfaces stop working.

Ask whether any drainage record exists showing this surface, what it connects to, and where anything associated with it sits.

A drainage record is the single document that would answer most of the questions in this checklist at once.

Ask whether any record describes what was actually built rather than what was originally proposed, and whether you may have a copy.

The two differ often enough that the distinction is worth making explicitly when you ask.

Where the store is open to the ground, ask whether any testing supported that and whether the result is held anywhere.

A record of what the ground was expected to do is what tells a future professional whether the arrangement behaved as assumed.

Look through the conveyancing pack, transfer and any estate documents for anything describing a drainage obligation on your plot.

Obligations attached to a plot sit in paperwork nobody reads at completion and stay attached regardless.

Where nothing can be found, write down what you searched for and who you asked, and treat the arrangement as unknown from then on.

An unknown arrangement is a legitimate finding, and it changes how every later proposal should be approached.

Treat any proposal to seal, coat or otherwise close the surface as a question to put to a drainage professional before it is agreed.

Sealing is proposed to improve appearance and has nothing in the conversation to indicate it removes a drainage duty.

Whether a surface may be sealed, coated or closed is a determination for whoever is responsible for the site drainage.

Treat a proposal to lay a new surface over the existing one as the same question, however thin the new layer is described as being.

An overlay is the cheapest-sounding option on a quotation and it can convert a drainage asset into an ordinary pavement.

Note that resurfacing only part of the area still changes what that part does, and ask about it even where most of the surface is untouched.

Partial work is exactly the kind that nobody thinks worth raising, and the effect is not proportionate to the area.

Where a new roof, extension or hard surface would drain onto the area, ask whether the arrangement was sized for that additional water.

Adding catchment is invisible at the surface and is the change least likely to be described as affecting drainage.

Directing additional water onto an existing surface is a drainage design question, and requirements vary by location and must be confirmed locally.

Ask before anything loose is spread, tipped or stored on the surface, including sand, soil, gravel, bark or builders' material.

Loose material works into the surface openings and cannot be recovered afterwards, which shortens the life of the arrangement.

Treat any proposal to build a store, outbuilding or base on part of the area as a question about the drainage as well as the structure.

An outbuilding removes both the permeable area and the access to whatever sits beneath it, permanently.

Note that stockpiling soil, aggregate or building material on the surface, even briefly, can affect what lies beneath it.

A heap left for a fortnight during a building project is the classic way a surface is disabled without anyone deciding anything.

Tell any contractor working at the property that this surface is part of the drainage, and write it into whatever you agree with them.

A contractor has no way of knowing, and the instruction has to reach the person actually unloading the lorry.

Note what regularly lands on the surface, including leaves, soil washed from beds, and material blown from a neighbouring area.

What arrives on the surface over the years is what eventually reaches the store beneath, so noticing the source is useful.

Note whether soil or mulch from an adjoining bed washes onto the surface, and record where that happens along its edges.

Material arriving from the side is a continuing supply rather than a one-off event, which makes its effect cumulative.

Ask what cleaning is appropriate, how often, and whether any method should be avoided, rather than assuming any cleaning is beneficial.

Cleaning is part of the arrangement rather than housekeeping, and the appropriate approach comes from whoever designed it.

The appropriate cleaning approach for a surface forming part of site drainage comes from whoever designed it rather than from general practice.

Note where vehicles turn, brake and stand on the surface, since those are the places where material is worked into it.

Wear happens where traffic manoeuvres rather than where it passes, and the difference shows up in the same places every time.

Go out during and after heavy rain and record whether water stands anywhere on the surface, and how long it takes to disappear.

How a permeable surface behaves after rain tells you far more than its age or appearance ever will.

Record that behaviour now as a baseline, with the date and the recent weather, so later observations have something to be compared against.

Change is what matters here, and change cannot be seen without an earlier observation to set it against.

Note where on the surface water stands rather than only that it does, and mark those areas on a sketch.

Position is what turns an observation into something useful, because it may point at one part of the arrangement rather than all of it.

Repeat the observation after any work at the property, including work that had nothing to do with this surface.

The changes that matter here are usually made during unrelated jobs, which is exactly why nobody thinks to look afterwards.

Describe what you observed rather than what you think it means, and take that description to somebody qualified if it has changed.

The units can remain sound for a long period while something beneath changes, so appearance is a poor guide to cause.

Write a short plain-language note saying what this surface is and what must not be done to it, and keep it with the property papers.

The person who eventually needs it is a contractor or a future owner, neither of whom will read a drainage drawing.

Include the note in whatever you give any contractor quoting for work at the property, not only work on this surface.

The jobs that remove the function are usually unrelated ones, so the note has to travel further than the surface itself.

Make sure everyone in the household knows, since deliveries and small decisions are taken by whoever happens to be at home.

A load of sand is accepted in seconds by somebody who has no idea the surface is anything other than a drive.

Keep your rain observations with the note so that a pattern over years is available rather than a single recent impression.

A record showing how the surface behaved over several seasons is far more useful than any description of it.

Decide now that the note and the records will be handed to a buyer at the point of sale, and write that intention down.

Handing it over is a deliberate act that only happens if the decision was taken long before the sale itself.