What does a chimney inspection cover?

The pots are the first thing we look at. Clay pots crack with frost, lose pieces with age, or tilt if their bedding has failed. A cowl or cap, if fitted, should be secure and undamaged. Our page on chimney pot replacement covers what happens when one has to come off.

Underneath the pots is the flaunching, the sloping mortar fillet that holds each pot in place and sheds rain off the crown. Being the most exposed mortar on the house, it is frequently the first part to give out. We look for cracks, hollow sounds where it has pulled away, and gaps around the pot where water can sit. A flaunching problem is cheap to fix when caught early and a good deal more expensive once water has been running into the stack for a season or two.

Pots on a shared stack sometimes belong to both houses, so we note which flues serve which side before anyone changes anything. A pot that is blocked, or sealed with a cap that lets no air through, is noted as well, because a flue with no airflow can leave damp showing indoors on the breast. Birds sometimes nest in open pots, and they are protected, so a check for nests comes before any work.

Where a pot has been capped, we also look at how the cap is fixed and whether the air path through the flue is clear, since a blocked flue invites condensation.

Next comes the brickwork. We check the mortar joints for recession, where mortar has crumbled back from the face, and for bricks with their faces flaking away, known as spalling. Hairline cracks, vertical splits and bulges each tell a slightly different story. A stack leaning out of plumb is a separate and more serious matter, discussed in our page on leaning chimneys.

Where a stack is rendered, we tap for hollow patches and look for cracks that let water behind the coating. Render that has failed traps moisture against the brick, so damage can be worse than it looks from outside. Our page on rendering a chimney sets out when it helps and when it is better left off. Low down, the brickwork also shows whether an earlier repair was made to a good standard, which affects how much of the stack we suggest touching.

Flashing is the lead (or sometimes a flexible substitute) that seals the join between the brickwork and the slates or tiles. Around a chimney it usually takes several parts: a front apron, stepped flashings up the sides, a back gutter behind the stack, and soakers, the small folded lead sheets that interleave with the covering. We look for lifted edges, cracks, splits at the folds, and pointing that has dropped out of the groove cut into the brick to hold the lead.

Lead has a long life when correctly installed, and the MyJobQuote cost guide of 22 September 2026 states that it can last over 80 years, so a flashing problem is often down to detail, fixing or a poor earlier repair rather than age alone. Most leaks around a stack start at this junction, which is why it gets careful attention at every inspection. Our chimney repairs hub links to the flashing and back-gutter pages for more.

Part of the stack is only visible from the loft, and we go up there when we can. We check the brickwork for damp staining, white salt deposits, loose mortar and any sign of water tracking down the timbers around it. We also look at how the stack is supported if the breast below has been altered, since that is a structural question, not a roofing one. Our page on a removed chimney breast explains the signs.

If you are able to, a quick look yourself with a torch before the survey helps, for instance at stained rafters or wet insulation. Please do not move stored items or step off the joists. The survey pictures go into the written quote that follows, so what we see is on record and you can look at it too.

Damp in the loft near a stack does not always mean the chimney is at fault, since a nearby valley or a gutter can be the source. Seeing the loft helps us tell the two apart. We also look at the roof timbers close to the stack, because wet rafters, battens or a wall plate that have been soaking for a while may need replacing at the same time as the brickwork is put right. A stack that looks fine from outside can still be passing water into the timber at its base.

Once we have seen all five areas, our notes put the findings in order of urgency: the items to deal with first, those that can be left a while and those that only need watching.

A first look is possible from the garden with binoculars or a long lens, from a ladder, from the roof, or by drone. Each has limits. The ground gives you the outline and the gross defects; a ladder or roof access lets us touch and photograph close up; a drone reaches high stacks and steep roofs without climbing. High stacks may need a scaffold, and our page on chimney scaffolding covers the options.

For national figures, MyBuilder's roof inspection guide, updated 21 August 2026, gives a standard inspection as £150 to £250 and a drone inspection as £200 to £400. Those are typical UK prices for roof inspections, not a Skyline figure. If you think the problem followed a storm, read our page on chimney insurance before anything is repaired, so you keep the evidence your insurer may want.

After the visit you have the pictures, the written quote and a plain list of what we found, which you can pass to a neighbour who shares the stack, to an engineer, or to your insurer. Nothing is repaired until you decide it should be.