Timber framing movement is common in New Zealand homes, particularly in older houses and those built with unseasoned timber. Most movement is minor and cosmetic, but some signs can point to more serious structural issues that need professional attention. Knowing what to look for helps you act early and avoid costly repairs down the track.
What Causes Timber Framing to Move?
NZ homes are predominantly timber-framed, and timber is a natural material that responds to changes in moisture content and temperature. Common causes of movement include:
- Seasonal shrinkage and swelling – timber expands when wet and contracts as it dries, especially in the first few years after construction
- Unseasoned or green timber – historically common in NZ builds, this timber continues to dry and shrink after the house is built
- Foundation settlement – gradual or uneven settling of piles, concrete pads or slab foundations can shift the framing above
- Subfloor moisture – poor ventilation under the floor can cause timber to absorb moisture and swell
- Earthquake damage – NZ's seismic activity can cause sudden or cumulative racking of frames
- Deterioration – borer, rot or fungal decay can weaken framing members over time
Key Signs to Look For
Cracks in Walls and Ceilings
Plasterboard (GIB®) cracking is one of the most visible signs of framing movement. Look for:
- Diagonal cracks running from the corners of door and window openings
- Horizontal or vertical cracks along plasterboard joins
- Cracks that are wider at one end (tapered cracks) — these suggest differential movement
- Recurring cracks that reappear after being filled and repainted
Hairline cracks are often just normal seasonal movement or settling. Cracks wider than about 2–3 mm, or cracks that are growing, deserve closer attention.
Sticking or Misaligned Doors and Windows
If doors or windows that previously opened smoothly now stick, bind, or no longer sit square in their frames, this is a strong indicator that the surrounding framing has moved. Check whether:
- The door or window frame is visibly out of square (use a spirit level)
- Gaps around the frame are uneven
- Latches and strikes no longer align properly
Uneven or Sloping Floors
Place a spirit level or a marble on the floor in several spots. A noticeable slope — particularly one that has developed or worsened over time — can indicate foundation movement, deteriorating subfloor framing, or pile settlement. Bouncy or springy floors may point to weakened joists or bearers.
Gaps Between Building Elements
Look for gaps appearing between:
- Skirting boards and the floor
- Cornices and the ceiling or wall
- Window or door architraves and the wall lining
- The wall framing and the ceiling
These gaps often open up as framing dries and shrinks, or as the structure shifts.
External Clues
Don't forget to inspect outside the house:
- Out-of-plumb walls – stand back and sight along the wall line; a bowing or leaning wall is a concern
- Gaps in cladding joints – particularly in weatherboard or fibre cement cladding
- Cracked or displaced exterior cladding – can indicate movement in the framing behind
- Roof ridgeline – a sagging or uneven ridge may suggest rafter or top plate movement
Subfloor and Roof Space
If you can safely access the subfloor or roof space, look for:
- Cracked, split or bowed framing members
- Evidence of borer (small round holes and fine dust) or rot (soft, discoloured timber)
- Piles that are leaning, cracked or no longer in firm contact with the bearer
- Sagging or displaced insulation that may be hiding damaged framing
How to Do a Simple Walk-Through Inspection
| Area | What to Check | Tool Needed |
|---|---|---|
| Walls & ceilings | Cracks, bulges, gaps at joins | Torch, eye |
| Doors & windows | Sticking, out of square, uneven gaps | Spirit level |
| Floors | Slope, bounce, squeaking | Spirit level, foot test |
| Exterior | Plumb walls, cladding gaps, ridge line | Eye, binoculars |
| Subfloor (if accessible) | Rot, borer, pile condition | Torch, probe |
Take dated photos of any cracks or gaps you find. This helps you track whether they are growing over time — a key indicator of ongoing movement versus historic, stable movement.
When to Call a Professional
While a homeowner can carry out a visual check, interpreting what you find is best left to a qualified professional. You should contact a licensed building inspector or Licensed Building Practitioner (LBP) if you notice:
- Cracks that are wide, growing, or recurring
- Floors with a noticeable slope or significant bounce
- Walls that appear to be leaning or bowing
- Multiple signs appearing together across the house
- Any signs of rot, borer or structural timber decay
- Damage you suspect may be earthquake-related
A professional building inspector will use a moisture meter, probe, and level to assess framing condition properly. If structural repairs are needed, work that affects the primary structure of your home will likely require a building consent from your local council — always check with them first. Structural repair work must be carried out or supervised by an LBP with the relevant licence class.
You can find qualified local building inspectors and LBPs on tradedirectory.co.nz.
Licensed Building Practitioner (LBP)
BCITO Qualified
