Addition Boundary and Overlooking Questions Checklist

Find the plan attached to your property papers and note what it shows along the side the addition would sit near, without concluding anything from it.

Owners frequently read the plan in their papers as a precise line, and how much weight it actually carries is a question for a qualified adviser.

Where a legal boundary runs can only be established by a suitably qualified adviser, never from a plan read at home.

Walk the boundary and photograph what physically marks it along its whole length, noting each point where the marker changes from one thing to another.

A change of fence type part way along usually records something that happened, and it is the first thing anybody will ask about.

Note any point where the fence, wall or hedge is obviously not straight, or where the line steps in or out.

Kinks and steps in a boundary often matter a great deal to a proposal that comes close to the line.

Write down what you have been told about the boundary by anybody at all, marking clearly who said it and when, without treating it as established.

Second-hand history is worth recording and worth labelling, because it is frequently the only account that exists.

Note whether any boundary marker has been replaced or repositioned during your time at the property, and describe exactly what changed.

Replacement fences are often put back in a slightly different position, and that is precisely what a boundary question turns on.

Leave every boundary marker where it stands while a proposal is being prepared, rather than tidying, moving or replacing anything.

Anything that alters the physical evidence makes the question harder for everybody involved to answer afterwards.

Do not alter a fence, wall or hedge on or near a boundary without advice from a qualified adviser.

List every structure standing on or hard against the line, including sheds, garages, stores and any wall that appears to be doing more than dividing.

Structures at a boundary raise ownership and support questions that take time to resolve, and starting early is the only remedy.

Note anything on the neighbouring side that leans against, drains onto or is fixed to a structure along the line.

What arrives from the other side is part of the same question and is easy to leave out of an owner's description.

Whether a structure is shared, and what that means for your proposal, must be confirmed with a qualified adviser.

Record any difference in ground level across the line and which side sits higher, without drawing any conclusion about what is holding it up.

Level differences at a boundary change what a proposal near the line has to deal with before anything is drawn.

What retains a level difference at a boundary, and what condition it is in, must be assessed by a suitably qualified professional.

Photograph every tree, hedge and substantial planting near the line, noting which side each one appears to grow from.

Planting close to a boundary raises questions of its own and can affect where anything is able to go.

Whether a tree near the line is protected, and what may be done near it, must be confirmed with the local authority.

Note any drain cover, gully, chamber or meter near the line, and which property each one appears to serve.

Shared or neighbouring drainage close to a boundary frequently decides what can be built and where.

Stand roughly where each proposed new window would be, as far as you can judge it, and write down what you would actually see from there.

Standing in approximately the right place produces a far more honest list than reading it off a drawing.

List every window on the neighbouring property that faces the proposal, noting roughly what room each one appears to serve.

The neighbouring windows are the other half of the question, and a proposal that ignores them is much harder to discuss.

Note which of your existing windows would lose or gain a view of the neighbouring property once the addition exists.

An addition changes your own outlook as well as theirs, and both changes belong in the record.

Consider what would be visible in each direction after dark, when lit rooms are far more exposed than they ever are in daylight.

Privacy is judged at night as much as in daylight, and it is very rarely tested that way while a proposal is being prepared.

Note any window on either side that is already obscured, high level or fixed shut, and photograph it before anything changes.

An existing arrangement records how the two properties have handled this question before, which is useful context to bring.

Write down which of your own rooms you would mind being seen into, and which you genuinely would not.

Privacy is not uniform across a house, and saying which rooms matter makes the design conversation considerably shorter.

Note where the neighbouring household actually sits outside, whether a patio, a bench, a play area or a door they leave standing open.

The place people genuinely use is what matters, and it is often nowhere near the boundary the proposal touches.

Consider what an upper window, dormer or terrace in the proposal would see of that space, and describe it plainly rather than optimistically.

Views from an upper level over a garden are the commonest source of objection and the least often anticipated.

Whether any degree of overlooking would be acceptable in your area can only be confirmed with the local authority.

Note where you sit outside, and whether the addition would improve or quietly worsen your own privacy in that spot.

Owners regularly design a proposal that solves an indoor problem and removes their own outdoor privacy along the way.

Treat any raised terrace, balcony or usable roof area in the proposal as its own topic, since standing outside is different from looking through glass.

An outdoor level is experienced by neighbours very differently from a window and should be discussed on its own terms.

Note whether the proposal would also be visible from the road, a shared path or anywhere beyond the properties either side.

Wider visibility is part of the same conversation and is easy to leave out when attention is fixed on one boundary.

Ask what options exist for reducing overlooking at each point on your list, and note all of them rather than settling on the first.

Several options on the table produce a better conversation than arriving with a single fixed idea already decided.

Consider whether an opening could sit higher, face a different way or be fixed rather than opening, and raise each of those as a question.

Small changes to an opening often resolve an overlooking point without altering the plan at all.

Whether an obscured, high level or fixed opening would be acceptable must be confirmed with the local authority and your designer.

Note anywhere planting is being relied on for privacy, and record that planting changes through the seasons and can be cut down.

Screening that depends on somebody else keeping a hedge is not screening you have any control over.

Note whether any screening under consideration would take daylight from your room or from theirs, and raise that trade openly.

Privacy and daylight pull against each other, and the trade should be a decision rather than a later discovery.

Write down what you would be prepared to change about the proposal and what you would not, before any conversation begins.

Knowing your own position in advance keeps a neighbour conversation calm and prevents promises you cannot keep.

Ask how the side of the addition nearest the line would be built, and whether anybody would need to stand on the neighbouring side to do it.

Access to build is the practical question that decides how close to a line anything can realistically go.

Any access onto neighbouring land must be arranged with the neighbour and confirmed with a qualified adviser.

Note whether any part of the proposal, including eaves, gutters or foundations, might reach towards or beyond the line.

The parts that project are commonly overlooked because they are not the part anybody draws first.

Whether any element may approach or cross a boundary must be established by qualified professionals and confirmed locally.

Consider how the wall, roof edge and gutter nearest the line would be cleaned, repaired or replaced once the addition exists.

A face nobody can reach again becomes somebody's problem later, usually at the least convenient moment.

Ask where scaffolding or working platforms would stand, and whether the neighbouring side would be affected while work is under way.

Scaffold position near a boundary is a conversation to have with a neighbour before it becomes a fact on the ground.

Note where rainwater from the new roof and any new hard surface would go, and check that nothing is assumed to run onto the neighbouring side.

Water arriving next door is one of the fastest ways a workable neighbour relationship comes apart.

Where rainwater and drainage from an addition may discharge must be established by qualified professionals and confirmed locally.

Decide at what point you would rather your neighbour heard about the proposal from you than from a notice or from somebody else entirely.

Being told early is what most neighbours say they wanted afterwards, and it is entirely within your control.

Write down what you would show them, and check that it contains nothing you are not yet reasonably certain about.

Showing a drawing that later changes creates a problem that did not need to exist in the first place.

Note what you would not promise, including anything about noise, timing, access or the finished appearance, until you can genuinely stand behind it.

Promises made across a fence are remembered exactly, and they are usually made about things somebody else controls.

Record what was said in each conversation and on what date, including anything the neighbour raised, asked for or objected to.

A plain written record of neighbour conversations is useful whether the relationship goes well or badly.

Ask what your neighbour is concerned about specifically, rather than assuming which part of the proposal is worrying them.

The part a neighbour minds is very often not the part an owner expects, and asking is quicker than guessing.

Confirm locally what applies to building close to a boundary at your property, and note the date and the name of whoever answered.

What was accepted a few streets away tells you very little, and only the responsible body can speak to this particular address.

Only the local authority can confirm what applies at your property; nothing on this page should be read as an answer.

Ask a qualified adviser what your papers say about responsibility for each boundary, rather than interpreting the plan yourself.

Responsibility for a boundary and ownership of the fence standing on it may not be the same question, which is why it is worth asking rather than assuming.

Ask what notice or agreement arrangements might apply where work would come close to a shared or neighbouring structure.

These arrangements have their own process and their own sequence, and finding out late is the usual complaint.

Notice and agreement arrangements for work near shared structures must be confirmed with a qualified adviser.

Note any covenant, right of way or shared access mentioned in your papers, and put each one to an adviser as a question.

Rights and covenants attached to a property routinely affect what can be built near a boundary and how it is reached.

Keep every boundary answer, whatever its source, in one file with its date, so the reasoning survives the design changing.

Boundary questions get revisited many times, and a single file stops the same ground being covered repeatedly.