Thermal Bridging Questions Checklist

Note exactly where each cold patch, mark or area of mould sits: which room, which wall, how high, and how close to a corner, ceiling or opening.

Position is what turns an anecdote into evidence, because bridging effects tend to sit in geometrically predictable places.

Write down whether marks form a line, a band or a repeating pattern rather than a random patch, and photograph them straight on in good light.

A repeating pattern often traces something behind the surface, and that observation is genuinely useful to whoever surveys it.

Note whether the wall surface itself feels cold to the hand while the room air feels warm, and in which conditions you notice it.

A cold surface in a warm room points at the construction rather than at heating, which changes the questions worth asking.

Record whether the same area is affected on more than one floor or in more than one room, and mark them all on a simple plan.

Repetition up or across a building suggests something continuous behind the finish, which is easier to discuss than isolated complaints.

Note the conditions in which the problem shows itself, such as cold spells, wet weather or after the heating has been off.

Conditions matter as much as location, and they are forgotten quickly once a mark has been wiped away.

Keep the record descriptive and resist writing down a cause, however obvious it feels while you are standing in front of it.

Establishing why a surface is cold or marked is a matter for a suitably qualified professional; a self-diagnosis in the record can send them the wrong way.

Note where the outside wall meets the roof at the eaves and at any verge, and write down whether you have ever seen how those meet inside.

The eaves are the classic pinch point where two separate layers have to become one and often do not.

Record where the outside wall meets the ground floor, and note whether cold or marks appear along the bottom of that wall in any room.

The wall to floor junction is hard to reach in an existing building and is regularly left out of a proposal entirely.

Write down which corners of the building feel coldest inside, including internal corners of rooms on the outside face.

Corners lose heat over a larger outside area than inside area, which is why the same corners keep coming up.

Note where an upper floor structure appears to build into the outside wall, and whether a band of marking sits at that height inside.

A horizontal band at floor level is a familiar observation, and it is one a professional will want to see photographed.

Record where an internal or separating wall meets the outside wall, and note whether the affected areas cluster around those points.

Anything involving a separating wall shared with a neighbour raises legal and party wall questions to put to a suitably qualified professional.

Draw up a plain list of the junctions in your building and take it to the meeting, asking how each one is intended to be handled.

A written list forces every junction to be addressed rather than only the ones easily drawn.

Note whether the plaster at the side of a window feels colder than the wall beside it, and whether marks gather at that edge.

Reveals are narrow, awkward to treat and therefore the first place a scheme compromises.

Record what happens beneath the window inside, including whether the board is cold, whether marks sit under it and what the outside sill looks like.

The sill carries the wall through to the outside in many constructions, and it is easy to photograph from both sides.

Write down whether the top of an opening shows marking, and note anything you know about how that head was formed or altered.

Openings that were widened or changed often have a different arrangement above them than the original ones.

Note where each frame sits within the thickness of the wall, whether close to the outside face, set well back or somewhere between.

Where the frame sits relative to the rest of the build-up is a question a designer will ask immediately.

Record any opening that has been enlarged, filled in or newly formed, and gather anything you hold about when that happened.

Altered openings frequently behave differently from the originals, and the history explains an otherwise odd pattern.

Ask who is responsible for the detail where the frame meets the wall, since it usually falls between the window supplier and whoever builds the opening.

Responsibility for the junction between a frame and the surrounding construction should be confirmed in writing with the professionals involved.

Record any balcony, canopy, projecting slab or step that appears to continue from inside the building to outside it.

A structure that runs straight through the wall is one of the most significant items to raise, and it is often taken as a given.

Note where you believe a beam, column or post sits within or against an outside wall, and how you know that.

Confirming what structure sits inside a wall is a matter for a suitably qualified professional working from proper information.

List every flue, extract terminal, vent and duct passing through an outside wall or roof, and photograph each one from outside.

Penetrations accumulate over the life of a building, and no plan ever shows all of them.

Write down where services enter the building, including water, drainage, electricity, gas, aerial and any later addition drilled through.

Service entries are made by whoever needed them at the time, and they are almost never revisited afterwards.

Note anything fixed to an outside wall that also connects to something inside, such as an outdoor unit, tap, meter box or light.

Items fixed through the wall are worth listing because they will have to be dealt with by somebody during any envelope work.

Record whether timbers appear to build into the outside wall at any floor or roof level, based on what is visible rather than assumed.

Timbers entering an outside wall are a common feature of older construction and change how a junction can be treated.

List everything hanging off the outside wall now: rainwater goods, a gate, a rail, a satellite fixing, a hose reel, a security light or a sign.

Each one is fixed back through whatever is on the wall, and they all need a home once the outside face changes.

Write down what you expect to fix to the wall afterwards, so the question is asked before rather than after the surface exists.

Fixing into a finished face without knowing what is behind it is how new problems get made.

Ask what holds any cladding, rail or heavy element back to the structure, and whether those supports pass through the insulated layer.

How a support is fixed back through a build-up is a technical detail for a suitably qualified professional, not a matter for assumption.

Note any handrail, balustrade or gate post that is fixed into an outside wall or into a floor that continues outside.

These attachments sit exactly on the line you are trying to keep continuous, which is why they need naming.

Record what you know about how each opening is supported, and treat anything you do not know as a question rather than a gap in the notes.

What supports an opening, and what it is made of, must be established by a suitably qualified professional rather than deduced from the finish.

Write down which rooms or elevations are being left untreated, and record whether they share a wall or a corner with treated areas.

The boundary between treated and untreated is where new patterns of marking tend to appear afterwards.

Note where an outside wall runs up to a boundary, an attached building or a neighbouring property, so the edge condition can be discussed.

Work up to or across a boundary raises ownership and party wall questions to put to a suitably qualified professional before anything is designed.

List anything that plainly cannot be treated as it stands, such as a decorative face you wish to keep or an area with no access.

Naming these early keeps a proposal honest instead of quietly assuming the whole face is available.

Ask how treating one part of the building could change how the untreated parts behave, and record the answer you are given.

Whether partial work moves a moisture or cold problem elsewhere is a professional judgement, and it should be asked before work rather than after.

Consider whether the untreated areas may be tackled at some later point, and note anything that should be left ready for that.

Small provisions made now can make a later stage far less destructive, but only if the intention is written down.

Ask which junctions are actually drawn in the information you hold, and which are being left to be resolved on site.

The undrawn junctions are the ones that get improvised, and knowing which they are is half the battle.

Ask to be shown how the insulating layer is meant to carry across each drawn junction rather than stopping at the edge of the drawing.

A layer that ends at the sheet boundary is a familiar way for a gap to be created without anyone deciding to create one.

Note where one trade finishes and another begins along the same line, and ask who is responsible for the continuity across that handover.

Most breaks happen at the boundary between two people who each thought the other was dealing with it.

Ask for photographs of each junction before it is closed up, taken from a consistent position and kept with the project record.

Once a junction is covered nobody can see it again, and the photographs are all that remain to answer later questions.

Ask who looks at the continuity of the line as work proceeds, and how anything found is recorded and dealt with.

Checking work as it proceeds is a role for a suitably qualified professional appointed for that purpose, not for the owner walking the site.

Agree what the household should leave alone during the work, particularly at junctions that are open and waiting for the next trade.

Well meant tidying at an open junction can undo careful work, and a clear rule avoids the awkwardness.

Keep dated notes of each observation, with the conditions at the time, so the pattern can be seen across different weather rather than remembered.

Memory smooths a pattern into a general impression, and dated notes keep the detail that makes it useful.

Photograph each affected area from one chosen viewpoint on every occasion, keeping a door frame, a corner or a socket in shot as a reference.

A mark that is slowly growing looks unchanged between casual glances, and only matching viewpoints will ever reveal it.

Ask what conditions a thermal or moisture survey would need to be meaningful, and what has to happen in the building beforehand.

Any survey of this kind should be carried out and interpreted by a suitably qualified professional, and its output is not self-explanatory.

Gather what you know about the age of the building and any earlier work to walls, roof or openings, even where it is only hearsay.

History explains most patterns, and marking a note as uncertain is far better than leaving it out.

Record how the affected rooms are heated and used, including any that are closed off, unheated or used quite differently from the rest.

Use and heating shape the pattern, and a surveyor who does not know them can be sent looking in the wrong place.