Cavity and Solid Wall Questions Checklist

Photograph a section of the brick or stone pattern on each elevation, including anywhere the pattern visibly changes partway up or along the wall.

The way an outer face is laid carries useful clues, and a photograph is far more reliable than any description an owner attempts.

Note roughly how deep the window and door reveals appear at different parts of the building, and hand that over as an observation rather than a conclusion.

Wall thickness alone establishes nothing about how a wall is built; ask a qualified professional to determine that before anything is specified.

Look for small filled holes in a regular pattern across an elevation, and photograph a group of them wherever you find them.

Regularly spaced patches often indicate that something was done to the wall in the past, and the pattern itself is worth showing to a professional.

Note where air bricks, small vents or deliberately open joints appear low down or beneath windows, and mark their positions on a rough elevation sketch.

Never block or fill an opening in an external wall; what each one does should be established by a qualified professional first.

Record where parts of the building look different in age or construction, such as a rear addition, a later extension or an opening that has been filled in.

Most houses are the result of several building campaigns, and each part can be built quite differently from the one beside it.

Tap along the inside faces of the outside walls and mark on your sketch which sound hollow and which sound solid, treating the result as a clue only.

This takes minutes and usefully flags where a lining may already exist behind the plaster, which changes the whole conversation.

Search whatever paperwork came with the property for any mention of work to the walls, including filling, treatment, repointing, rendering or tie replacement.

Owners frequently hold the answer already, filed with the conveyancing papers and never read since the day they moved in.

Ask previous owners or long standing neighbours what they remember being done to the building, and write down who told you what and when.

Recollection is not evidence, but it points an investigation in a direction, which is often all that is needed.

Look for a plaque, label or sticker in a meter cupboard, a loft, a cellar or a service cupboard, since records are often left in unlikely spots.

Installers sometimes leave a record on site, and it can be the only surviving evidence of what was actually done.

Gather any survey or assessment report you already hold and note what it says about the walls, marking that description as a claim to be confirmed.

Descriptions of wall construction in existing reports are often assumptions rather than findings; ask a qualified professional to confirm them.

Record whether neighbouring properties in the same terrace, row or estate have had work of this kind, and what they were told at the time.

Similar houses were often built the same way and treated within the same programme, so a neighbour's paperwork can be a useful lead.

Write down which statements about the walls came from someone with no responsibility for them, and label those clearly as unconfirmed.

Look at the building during or just after heavy rain if you safely can, and note which walls are visibly wetted and which stay comparatively dry.

One observation made during real weather is worth more than any general assumption about which side of a building is exposed.

Record whether the property is sheltered by other buildings, trees or rising ground, or whether it stands open on one or more sides.

Shelter varies enormously between houses on the same street, and it changes how the same wall construction behaves.

Note how long each elevation takes to dry after rain, and whether one face stays dark long after the others have cleared.

Drying behaviour is something only an occupant sees, and it often explains why one wall causes trouble and its neighbour does not.

Mark and photograph anywhere water visibly runs down the wall from a gutter, a joint, a sill or an overflow, including the staining it leaves.

Water running over a wall face has a source that should be traced by a qualified professional rather than treated as a wall problem.

Note where soil, paving, decking or planting sits high against the wall on any elevation, and describe it rather than deciding what it means.

Ground levels beside a wall are read differently by every trade; ask a qualified professional to look at them on site.

Record whether any elevation is regularly splashed by passing traffic, a downpipe discharge or a path that sheds water back towards the house.

Mark on a room by room sketch exactly where damp, staining or mould appears, at roughly what height and on which wall of the room.

Where a mark sits on a wall is one of the most useful pieces of information anybody investigating can be handed.

Note whether marks appear or worsen with particular weather, or whether they are present all the time regardless of conditions.

A mark that follows the rain and a mark that never changes usually point in quite different directions.

Record whether damp shows as a patch, a band across the wall, a stain at a corner or a ring around an opening, using plain words.

The shape of a mark carries information, and describing it plainly saves considerable time on a first visit.

Photograph each affected area with something ordinary in the frame for scale, such as a light switch, a skirting board or a door handle.

A photograph with no reference in it is hard to interpret months later, and this small habit makes the whole record usable.

Note where you have redecorated over a mark and how quickly it came back, since that history is genuinely useful to whoever investigates.

Owners often think redecorating is an embarrassment to admit to, when it is actually evidence about how the wall behaves.

Resist drawing conclusions about the cause and simply describe what you see, when you see it and how it changes through the seasons.

Establishing the cause of damp requires qualified investigation; be wary of accepting a cause from anyone who is also selling the remedy.

Photograph the head of several windows and doors from outside, showing what sits directly above each opening on that elevation.

What happens above an opening is among the first things anybody looking at a masonry wall will want to see for themselves.

Note everything that passes through the wall, including an extract duct, a flue, a pipe, a cable entry or an old vent that has been sealed up.

Anything passing through an external wall, and a flue or extract in particular, must be considered by a suitably qualified professional.

Record where a porch, lean to, conservatory or outbuilding is built against the wall, and photograph how it joins the main building.

Junctions between an original wall and something added later are frequently where water finds a way in.

Note where a boundary wall, garden wall, planter or set of steps abuts the outside face, and photograph how each one meets it.

Structures butting into a house create paths for water that are easy to walk past every day without ever noticing.

Look for a horizontal line of different mortar or a change of course low down on the wall and photograph it without interpreting what it is.

A visible line low on a wall may or may not be significant; what it is should be established by a qualified professional rather than assumed.

Record whether any window or door opening has been filled in, and whether the infill is visible from outside, from inside or from both.

Ask what would actually be done to establish the construction before anything is proposed, and whether that involves opening up or a survey hole.

A proposal made without any investigation is a guess, however confident and well presented it happens to sound.

Ask what happens if a cavity, where one exists, turns out to be partly filled, obstructed or bridged in places rather than clear throughout.

What lies inside a wall cannot be known from outside; ask a qualified professional what investigation would establish it here.

Ask what the proposal assumes about ties, trays and anything crossing the wall, and how each of those assumptions would be checked.

Ties, trays and cavity crossings are matters for a qualified professional to assess, never for an owner to judge from photographs.

Ask what the condition of the pointing, render or masonry means for the proposal, and what would need putting right before anything else happens.

Most wall work assumes the outer face is in reasonable order, and that assumption is worth surfacing before it is quietly relied upon.

Ask what the process would be if the proposal turned out to be unsuitable once the wall was opened up, and who carries that outcome.

How somebody answers a question about their assumptions failing tells you a great deal about who you are dealing with.

Ask whether what is proposed can be removed or reversed later, and what that would involve if it ever had to be done.

Some treatments are difficult to undo; ask a qualified professional what removal would involve before anything at all is agreed.

Keep your photographs sorted by elevation and by room rather than in one undated pile, and note when each set was taken.

A set of images somebody can navigate quickly is worth far more than a larger set nobody can find anything in.

Write down the questions each professional could not answer, and watch for the same gaps recurring across different visits.

The questions nobody can answer are usually the ones that matter, and the pattern across several visits is informative in itself.

Record who has visited, what they said the walls were made of and what evidence they based that statement on.

Confident statements about wall construction are common; the basis given for them is the part actually worth writing down.

Keep simple notes of the weather at the times you observed damp, in your own plain words rather than attempting any technical measurement.

Note anything you were told that contradicts something else you were told, and put that contradiction back to both parties in writing.

Contradictions tend to dissolve quietly unless somebody names them, and the owner is usually the only person in a position to do so.

Hold the evidence together in one place so a later adviser can see the whole history rather than beginning again from nothing.

Wall problems are often revisited after some years, and the earlier record is what stops the same ground being covered twice.