Vegetated Roof and Facade Ownership Questions Checklist

Ask who has looked at what the structure beneath or behind the planting would carry, and note their name and the date rather than the conclusion alone.

On an existing building this is the question that decides whether the idea is possible at all, and it belongs to an engineer.

What any structure can carry is a determination for a qualified engineer for your particular building. Nothing here establishes it.

Ask explicitly whether the assessment considered the assembly saturated rather than as it would be on the day it is installed, and write the answer down.

A planted system holds water by design, and the saturated condition is the one the supporting frame has to be designed around.

For a planted wall, ask what the support frame is fixed back to, and whether it reaches the structure or only the cladding in front of it.

Cladding was designed to carry itself, and what a bracket actually reaches is a question that has to be settled before fixing.

Ask how many fixings and water lines would cross the construction behind the planting, and where each of those crossings would be.

Each crossing is made in a permanently damp location and then covered by planting, which is why it is worth counting them early.

Ask what is proposed between the planted assembly and the construction behind it, and what that separation is doing.

The separation is what keeps a damp system from becoming a damp building, and an owner should at least know it is there.

For an existing roof, record what the covering is, roughly how old it is, and what you know about when it was last worked on.

A planted layer makes the covering beneath it far harder to reach, so its current state is part of the decision.

Ask directly whether the proposed planting depends on irrigation, or is intended to survive on rainfall, and record which answer you were given.

These are very different commitments, and the answer is often assumed on both sides rather than stated once clearly.

Ask where the irrigation water would come from, whether that is a mains connection, a stored supply, collected rainwater or something else.

The source decides what has to be installed, what has to be maintained and what happens in a dry spell.

Ask what would happen to the planting if the supply were interrupted for a period, and how you would know it had been interrupted.

Dieback in a band across a wall is a late symptom, and owners generally learn about the failure by seeing the plants brown.

Ask what controls the watering, where that control sits, and whether it is something a household can operate and adjust themselves.

A control the owner cannot reach or understand becomes a call to somebody else every time anything changes.

Note whether the irrigation needs power, where it would be taken from, and whether the water use would appear on your own supply.

These are ordinary running considerations that are easy to establish early and awkward to discover after handover.

Ask what happens to the irrigation in cold weather, whether anything has to be drained or isolated, and who would do it.

Seasonal tasks on an irrigation system are exactly the kind of obligation that arrives with a building and nobody mentions.

Ask where every drainage outlet, gully and overflow serving the planted area is, and get them marked on a drawing you keep.

Once planting is established these are invisible, and the drawing is the only way anyone will find them again.

Ask how each outlet would be reached and cleared once the planting is established, and whether that means dismantling anything around it.

Whether outlets can be cleared without taking things apart is decided when the layout is set out, not when they block.

Ask where water would go if an outlet were blocked, and whether that destination is the building, the paving or somewhere designed for it.

A blocked outlet does not stop the supply, and where the water then goes is a design question rather than an accident.

Note what is directly below the planted area outside, and ask what discharge arriving there would do to that surface over time.

Run-off onto paving produces staining and slipperiness, which becomes the owner's problem rather than the designer's.

Ask what happens to growing medium that migrates downwards over time, where it would collect, and who would be expected to remove it.

Medium moving down a vertical or sloped assembly ends up somewhere, usually in the drainage route it was meant to avoid.

Ask for a marked drawing showing the drainage route for the planted area and keep it with the building's own records, not the project file.

The project file gets archived; the building record is what the next person to deal with the roof will actually look for.

Irrigation, drainage and water demand for a planted assembly are determinations for qualified professionals, not owner estimates.

Ask how a person would physically get to every part of the planted area, and whether any of it could only be reached from outside the building.

Access provision is designed with the building and constrains everything that can be done to the planting later.

Work at height and access equipment are matters for qualified people. Record how access is provided; do not plan the method yourself.

Ask which parts of the planted area would be inspection-only or unreachable, and mark those areas on the drawing you keep.

Knowing which parts cannot be attended to tells you where a problem would go unnoticed for the longest.

Ask what access provision is actually included in the project, and whether anything further would have to be arranged separately by you.

Access is frequently described as available in principle without anything being included in the work itself.

Note whether reaching any part of the planting would need equipment standing on ground you do not own, and write that down as an open question.

An access route that depends on a neighbour is a permanent condition of the design rather than a one-off arrangement.

Ask whether anything is to be permanently fixed to the building for access, what maintains it, and what documentation comes with it.

Fixed access provision is itself something that has to be looked after, and its paperwork should reach the owner at handover.

Before handover, walk the route a person would take to reach the planting and note anything that has ended up in the way.

Access intended on a drawing is regularly obstructed by something installed later by a different trade.

Ask what the planted element is expected to need over a year, described as tasks rather than as a general reassurance about low maintenance.

A task list can be handed to somebody; a reassurance cannot, and the difference appears in the first year.

Ask who is expected to carry out each task, and whether the answer assumes the household, a contractor or a specialist.

Designs frequently assume a specialist regime that nobody ever arranged, which is how planted elements start to fail.

Note what each task assumes about skills and equipment, particularly anything that involves height, water systems or working on a roof.

An owner can do a good deal at ground level and very little above it, and the split should be clear before handover.

Ask what the first year after planting involves, and whether establishment care is included in the work or begins with you.

The establishment period is when neglect does the most damage and when responsibility is least clearly defined.

Ask what should be written down each time anything is done to the planted element, and start that record at handover.

A simple dated log is the only evidence that a regime was followed, and it is usually what a later question turns on.

Check whether any consent, lease, warranty or agreement attaches an obligation about the planting, and keep those wordings together.

Obligations of this kind are written in documents owners rarely re-read, and they outlast everyone involved in the project.

What any consent or agreement requires of you is a question for the relevant authority and for your own adviser.

Ask what the first visible signs of neglect would be, and where on the building you would see them.

Knowing the early signs is what lets an owner act before a horticultural problem becomes a building one.

Ask which consequences of neglect could be put right easily and which would be difficult or costly to reverse, in plain terms.

Owners can live with reversible consequences; it is the irreversible ones that need to be understood before committing.

Ask what the construction behind the planting would experience if the drainage stopped working, and how you would find out.

Consequences behind a planted face appear inside the building long before they appear on the plants themselves.

Ask what would be involved in taking the planted element off altogether, and what the building would be left with if you did.

An honest removal answer is the clearest measure of how permanent the commitment really is.

Ask what keeps roots away from joints, penetrations and the construction behind, and what would happen if that stopped working.

Root behaviour over time is one of the distinguishing features of a living envelope and it is easy to leave undiscussed.

Write down honestly whether your household would realistically carry out the regime described, and share that answer with the design team.

A design can respond to an owner who says they will not maintain something; it cannot respond to a polite silence.

Ask for a drawing of the planted area marking outlets, overflows, irrigation lines, controls and isolation points, and keep it with the property papers.

This single drawing is the most useful document a planted element can hand over, and it is frequently never produced.

Collect the documentation for the growing system, for the irrigation components and for anything fixed to the building for access, and keep it in one folder.

What any of these require is set by their own documentation, and a folder assembled at handover is the only chance to gather it.

Ask for a record of what was planted and roughly where, so replacements can match and dieback can be recognised for what it is.

Without this, every later question about the planting starts with somebody trying to identify what is there.

Photograph the planted element from several positions at handover and keep the dated images as the baseline for its condition.

A living surface changes continuously, so a dated baseline is far more useful here than on any other part of the envelope.

Write down who installed the planting and the irrigation, and what each of them said they would respond to after completion.

Two or three separate parties are typically involved, and owners lose track of which one deals with what.

Put the seasonal tasks into whatever calendar your household actually uses, rather than leaving them in a handover document.

A regime that is not in a calendar is a regime that will be remembered for one season and then quietly dropped.