Ceiling Repairs

Is a sagging ceiling dangerous?

A sagging lath and plaster ceiling should be treated as a live risk: the sag means the plaster keys holding it to the laths have broken, and a section can come down without further warning. Keep people from under it, don't prod it, and get it inspected promptly — same-day if it is dropping visibly.

The severity test is movement. A slight historic belly that has not changed in years is common in period ceilings and can often be stabilised or overboarded in ordinary time. A sag that has appeared recently, grown, cracked at its edges or started shedding flakes is a ceiling in motion — old lime plaster is astonishingly heavy, a square metre can weigh 25 kilos or more, and furniture and children do not negotiate with it. If part has already fallen or is hanging, treat it as a ceiling collapse emergency and call us rather than waiting for a quote slot.

We inspect from above through the loft or floorboards where access exists — the only honest way to see how many keys survive — and from below with a straightedge and gentle pressure. Then you get a plain verdict: stable and monitorable, repairable, or down it must come. What we will not do is screw a cosmetic patch over a ceiling that is telling everyone it wants to leave.

Repair, overboard or replace: what does your ceiling need?

Repair when damage is local and the rest of the ceiling is sound — a patch, a water-damaged section, a crack. Overboard when the surface is failing broadly but the structure above is good: new plasterboard screwed through to the joists, then skimmed. Replace — pull down and re-board — when lath and plaster has failed extensively.

Overboarding is the workhorse of ceiling renovation and usually the best value: the old ceiling stays up (no demolition, a fraction of the dust), new boards go through it into the joists so the fixing is structural, and a skim gives a flat new surface — typically £350–£600 a room. It suits tired-but-attached lath and plaster, crazed Artex (tested first — more below), and stained ceilings past cosmetic rescue. Its limits are honest ones: it adds a little weight and loses 15mm or so of height, and it must never be used to trap an actively failing ceiling, because screws through loose plaster just suspend the problem above your head.

Full pull-down and re-board is the right call perhaps one time in five: extensive key failure, historic water saturation, or sags across most of the room. It is dusty, disruptive, and we say so up front — rooms sheeted and sealed, debris bagged and gone the same day — and what you get back is effectively a new ceiling, flat and good for another century. Where original ornate cornice exists, we work carefully to preserve it, which is half the craft in period homes.

How do you repair a water-damaged ceiling?

In strict order: stop the leak, let the ceiling dry fully, then repair — cut out and re-board sagging or soft sections, or skim where the board survived — and always apply a stain-blocking primer before repainting. Skip the stain block and the brown ring bleeds through every coat of emulsion you ever apply.

The drying stage is where patience pays. Plasterboard that got briefly wet and dried flat often keeps its strength and needs only the stain treated and the surface reskimmed. Board that stayed wet — under a slow tank leak or a long-unnoticed drip from pipework above — loses its rigidity, bellies between joists and must come out, along with any sodden insulation sitting on top of it. We test with a moisture meter rather than by eye, because a ceiling can look dry weeks before it is.

For insurance claims we make the process easy to evidence: photographs of the damage before and during the work, a written scope and quotation that a loss adjuster can process without a second visit, and the repair sequenced so the leak fix is documented first. Once repaired and skimmed, the finish is blended so the repair disappears — the standard for a patch-and-skim is that nobody can point to where it was.

What do ceiling repairs cost in Surrey?

Small ceiling patch repairs start from around £120. A full ceiling skim runs £200–£350, overboarding and skimming a whole ceiling £350–£600, and pulling down a failed lath and plaster ceiling and re-boarding sits above that, priced by room size and access once we have seen it.

Water-damage repairs span the whole range depending on how much board and insulation must be renewed — a kettle-sized stain with sound board is a patch-and-stain-block day at the bottom of the scale, while a saturated bathroom ceiling with sodden loft insulation above is a strip-out. Lath and plaster work prices on the inspection: stabilising and overboarding a Victorian ceiling costs materially less than taking it down, which is one more reason to call before the ceiling makes the decision itself.

Every job gets a fixed written quote, and for insurance work the quote doubles as the scope document your insurer needs. One honest warning about cheap fixes: a skim over a failing ceiling is the most expensive £250 you can spend, because you pay again — plus the redecoration — when the real problem resurfaces through it.

Cracks in the ceiling: cosmetic or structural?

Most ceiling cracks are cosmetic: hairlines along plasterboard joints, shrinkage around newer work, and crazing in old surfaces. The ones that warrant attention are cracks wider than about 3mm, cracks paired with sagging, stepped or spreading cracks, and any crack that reopens repeatedly after proper filling.

The geography of the crack tells the story. Long straight lines are almost always board joints flexing — an adhesion and movement issue, fixed permanently by taping, filling and skimming rather than by chasing them with filler every spring. A crack tracing a single line across mid-ceiling often follows a joist; if the floor above bounces as someone walks, the joist is flexing and the crack will return until the movement is addressed. Map-like crazing on an older ceiling is the finish ageing, not the structure — and if that crazed texture is Artex applied before 2000, it may contain asbestos, so it gets lab-tested before anyone sands or scrapes; our Artex removal page explains the safe routes.

Genuine structural cracking — wide, stepped, growing, or matched by cracks in the walls — is rarer and bigger than plastering, and we say so when we see it: a structural engineer looks first, we repair after. Being the trade that tells you that honestly is, we find, why people call us back for the next thirty jobs that are just plaster.