Inside the house: ceilings, walls, floors and doors
Inside, most problems are either cosmetic wear or a sign of something happening elsewhere: movement in the structure, moisture, or loads in the roof space. Ceilings need the most attention: a loud cracking sound, sagging sheets or cornices, and a line of small circles or blisters (nail pops) can be warning signs of collapse and need prompt repair. Squeaky or bouncy timber floors point to fixings or the subfloor; cupped boards point to moisture below. Hollow or cracked tiles suggest movement or failed adhesive, and doors that stick can be seasonal swelling or structural movement. Older vinyl flooring and wall sheeting may contain asbestos.
- 01CeilingsCracking sounds, sagging and nail pops need prompt action
- 02FloorsBounce and slope point to the subfloor; cupping to moisture
- 03DoorsSeasonal sticking or year-round movement
Most interior signs are clues about the structure, the roof or the moisture.
What you'll notice
Walk each room and use all your senses. Some signs below are urgent; the ceiling signs in particular should not be left.
| Sense | Sign | Where to read next |
|---|---|---|
| Hear | A loud cracking sound from the ceiling | Urgent; see ceilings |
| See | A ceiling or cornice that sags, drops or bulges | Urgent; see ceilings |
| See | A line of small circles or blisters (nail pops) across a ceiling | Ceilings |
| See | Cracks in plaster walls, especially from door and window corners | Walls |
| Hear | Squeaks or creaks as you walk | Floors |
| Feel | Bouncy, springy or sloping floors | Subfloors |
| See | Timber boards that are cupped (edges higher than the centre) or have widening gaps | Floors |
| Hear | Hollow sounds when tapping floor or wall tiles | Tiles |
| Feel | Doors that stick, swing open or will not latch | Doors |
Ceilings: the signs that need prompt action
Ceiling collapses are rare, but they happen, often with warning signs that owners did not recognise. Western Australia's building regulator reports about 10 ceiling collapses each year there, and lists the warning signs: a loud cracking sound, sagging or dropping of the sheets or cornice, and visible cracking or a line of small circles or blisters (nail pops), which can mean the sheeting is pulling away from the framing above (WA Building and Energy).
If you see these signs, keep people out from under the area and have a ceiling fixer or builder brace and inspect it. Common causes include failed adhesive or fixings, loads stored or installed in the roof space, people walking on ceiling joists, and moisture from leaks or exhaust fans venting into the roof. The regulator's guide advises against storing items in the roof space and recommends that exhaust fans discharge outside.
| Type | Where you find it | What to watch |
|---|---|---|
| Lath and plaster | Many pre-war homes | Plaster can lose its grip on the timber laths and sag or drop in sections; cracks and bulges matter |
| Fibrous plaster sheets | Many homes from the early twentieth century to the post-war decades | Sagging where fixings have weakened; ornate cornices and roses can be heavy |
| Plasterboard | Most homes from the post-war decades onward | Nail pops, joint cracks, sagging between joists, water damage |
Hairline cracks along the cornice that open and close with the seasons are common and usually minor; see the cracks guide. Water stains on a ceiling point upward to the roof or a bathroom; see roofs and leaking showers.
Walls
Internal walls are usually plaster on masonry in older homes and plasterboard on a frame in newer ones. Cracks from the corners of doors and windows often reflect movement in the structure or footings, and are worth reading as a pattern in the cracks guide. Nail pops and joint cracks in plasterboard are common and usually cosmetic. Plaster that sounds hollow or crumbles, or stains low on walls, points to damp; see damp and moisture. Older wall sheeting, especially in wet areas, may contain asbestos; see asbestos in the home.
Floors
| Sign | Usual cause | Next step |
|---|---|---|
| Squeaks and creaks | Boards moving against fixings or each other | Re-fix the boards; usually minor |
| Bounce or springiness | Decayed, undersized or poorly supported joists or bearers | Check the subfloor |
| Sloping or uneven floor | Settled or failed stumps, or footing movement | Subfloors and restumping |
| Cupping (edges higher than centre) | Moisture from below, such as a damp subfloor or a leak | Find the moisture before sanding or replacing |
| Gaps that widen in winter | Seasonal shrinkage, often worse with heating | Usually normal; avoid filling gaps rigidly |
| Soft or crumbling boards | Decay or termite damage | Termites and a timber pest inspection |
Under carpet or floating floors, the structural floor is hidden; lift a corner where it is easy, or check the subfloor. Older vinyl tiles and the backing of sheet vinyl may contain asbestos, so test before lifting old floor coverings; see asbestos in the home.
Tiles
Tap tiles gently with a coin or knuckle. A hollow (drummy) sound means the tile has lost its bond; a few at edges is common, but widespread hollow tiles, cracked tiles or tiles that lift suggest movement in the floor below, failed adhesive or water underneath. In wet areas, hollow tiles can be a sign of a leaking shower; see leaking showers.
Doors
A door that sticks only in wet or humid weather is often seasonal swelling, and may need little more than adjustment. A door that sticks or swings in all seasons, has an uneven gap at the top, or sits in a frame that is visibly out of square suggests movement in the wall, floor or footings. Read it together with any cracks nearby and the level of the floor across the doorway.
Internal stairs and balustrades
Loose handrails, wobbly balusters and worn treads are safety issues, not cosmetic ones. Balustrades where someone could fall more than a metre follow the same rules on height, gaps and climbing as decks and balconies; see balustrades. Many older stairs predate these rules.
Common misreads
| What people say | What is closer to right |
|---|---|
| "A sagging ceiling is just cosmetic" | Sagging sheets or cornices, cracking sounds and lines of nail pops can precede a collapse. Act promptly. |
| "Squeaky floors mean the house is failing" | Usually loose boards. Bounce and slope are the signs that point to the subfloor. |
| "Gaps between boards mean a problem" | Seasonal gaps are normal; cupping and soft boards are the ones to investigate. |
| "The roof space is spare storage" | Ceilings are not designed to carry stored loads; storage can stress the ceiling below. |
Worked example: a line of nail pops in the living room
Illustrative reasoning example, not an inspected property. In a 2006 house, the owner notices a straight line of small round blisters across the living room ceiling and a faint crack along one cornice. Boxes have been stored in the roof space above for several years.
The pattern matches the regulator's warning signs: sheeting may be pulling away from the framing. The immediate step is to keep people out from under the area, remove the stored load from the roof space, and have a ceiling fixer inspect and brace the ceiling. Repair now is far cheaper than a collapse. Record the work in the home record.
Frequently asked questions
What are the warning signs that a ceiling may collapse?
A loud cracking sound, sagging or dropping of the ceiling sheets or cornice, and visible cracking or a line of small circles or blisters (nail pops). Keep people out from under the area and have it braced and inspected promptly.
Are cornice cracks serious?
Fine cracks along the cornice that open and close with the seasons are common and usually minor. Cracks with sagging, a dropping cornice or cracking sounds need prompt inspection.
Why are my floorboards cupping?
Cupping, where board edges sit higher than the centre, usually means moisture from below, such as a damp subfloor or a leak. Find and fix the moisture before sanding or replacing boards.
Why is my timber floor bouncy?
Usually because joists or bearers beneath are decayed, undersized or poorly supported. Have the subfloor inspected.
What does a hollow sound from floor tiles mean?
The tiles have lost their bond. A few at the edges is common; widespread hollow, cracked or lifting tiles suggest movement, failed adhesive or water below, and in a bathroom can signal a leaking shower.
Why does my door stick?
If only in wet weather, usually seasonal swelling. If it sticks all year, swings open or sits in a frame out of square, look for movement in the walls, floor or footings.
Can I store things in the roof space?
It is best not to. Ceilings are not designed to carry stored loads, and regulators warn that roof-space storage can stress the ceiling below.
How this guide was researched
We walk the interior by element, start from what owners notice, separate cosmetic wear from signs of movement, moisture or overload, and flag the ceiling signs that need prompt action, with a fictional example.
Limits: Interior signs often point to causes elsewhere in the building; confirmation may need subfloor, roof-space or specialist inspection.
Sources
- Be aware of the signs of a stressed ceilingWA Department of Energy, Mines, Industry Regulation and Safety (Building and Energy) · accessed
- Spontaneous ceiling collapseWA Department of Local Government, Industry Regulation and Safety · accessed
- Asbestos in the homeAsbestos and Silica Safety and Eradication Agency · accessed
- Building Technology Resources (foundation maintenance, condensation, managing termites, asbestos)CSIRO · accessed
- Housing Provisions Part 11.3: Barriers and handrailsAustralian Building Codes Board · accessed