Cracks in New Build House: Is This Normal?

You’ve just purchased a brand new home and cracks are appearing in the walls. The builder says this is normal settlement, but you’re not convinced. After all, “new” should mean “perfect,” right?

Wrong. Almost every new build develops minor cracks during the first two years.

Why New Builds Crack

Fresh materials contain moisture that escapes over time. Concrete slabs dry out. Timber frames shed water absorbed during construction. Plaster releases moisture as it cures. This drying process causes materials to shrink slightly, creating stress that manifests as hairline cracks.

The building settles onto its foundations. Even well-compacted ground compresses slightly under a new structure’s weight. This settlement happens most dramatically during the first 12 months, then gradually slows. Most foundations drop 5-10mm during this period.

Seasonal changes affect new builds more dramatically than established homes. The first summer causes expansion. The first winter brings contraction. Materials haven’t yet completed enough cycles to stabilise. Expect minor cracking after each seasonal transition for the first 2-3 years.

Normal vs Concerning Cracks in New Builds

Hairline cracks under 1mm width appear in most new properties. You’ll find them along plasterboard joints, around door frames, and where walls meet ceilings. These surface-level cracks affect only the decorative finish, not structural elements.

Stepped cracks through brickwork exceeding 3mm aren’t normal settling. They indicate foundation problems or inadequate wall construction. Builders cannot dismiss these as settlement. The NHBC (National House Building Council) classes cracks over 5mm as significant defects requiring investigation.

Vertical cracks along mortar joints rarely cause concern. Horizontal cracks through bricks themselves always need assessment. Horizontal cracks indicate excessive stress, possibly from inadequate cavity wall ties or foundation movement.

Timeline Expectations

Months 0-6: Most cracks appear during this period. Plasterboard joints crack as the house dries. Small vertical cracks appear around windows and doors. These early cracks rarely widen beyond 1-2mm.

Months 6-12: Seasonal movement creates a second wave of minor cracking. Cracks that appeared and stabilised earlier might extend slightly. New cracks emerge at stress points as the building completes its first annual temperature cycle.

Months 12-24: Cracking should slow significantly. New cracks appearing in year two need careful monitoring. They might indicate problems not related to settling, such as inadequate foundations or poor construction.

After 24 months: The structure has settled. Cracks appearing beyond two years rarely relate to normal settlement. They suggest new problems have developed or original construction defects are manifesting.

NHBC Coverage and Expectations

NHBC warranty covers structural defects for 10 years. During the first two years, builders must fix all defects, including minor cracks. Between years 2-10, coverage extends only to major structural problems.

Cracking classified as Category 2 or above (3mm+ width) qualifies for warranty claims. Category 0-1 damage (under 3mm) might not trigger warranty repairs, though reasonable builders fix these anyway.

Submit formal complaints in writing to your builder, copying NHBC. Keep detailed records of all communication. Take monthly photographs of cracks. This documentation proves invaluable if disputes escalate.

Construction Methods Matter

Timber frame homes experience different cracking patterns than masonry construction. Timber frames settle more quickly, usually within 6-12 months. Cracking concentrates around plasterboard joints. Once the frame stabilises, cracking largely ceases.

Masonry homes take longer to settle. Brick and block walls compress gradually under load. Settlement continues for 18-24 months typically. Cracking appears both internally in plaster and externally in mortar joints.

Modern trenchfill foundations reduce settlement cracking. These deep concrete foundations extending below frost level provide excellent support. Older-style strip footings, even in new builds, might allow more settlement on certain soil types.

When to Push Back on “Normal Settlement” Claims

Builders use “settlement” to dismiss genuine defects. You need to distinguish between acceptable settling and unacceptable workmanship or design failures.

Doors that no longer close properly within six months indicate excessive movement. Minor adjustment is normal. Replacing doors or frames because of warping suggests problems beyond settling.

Multiple cracks appearing in identical locations across several properties indicate systematic construction issues. If your neighbours in identical houses show the same cracking patterns, the builder can’t claim isolated settlement issues.

Cracks that reappear immediately after repair need investigation. Filling cracks that reopen within weeks suggests active movement beyond normal settling. Demand proper diagnosis before accepting repeated cosmetic repairs.

Your Rights Under Consumer Protection

The Consumer Rights Act 2015 protects new build buyers. Homes must be built with reasonable skill and care. They must be fit for purpose. These requirements override builders’ attempts to dismiss defects as normal.

Defects appearing within six years allow for claims against the builder. The first six months create a presumption that defects existed from day one, shifting the burden of proof to the builder.

Keep records of every defect report. Send written complaints, not just verbal mentions to site managers. Written records create evidence trails needed for legal action if relationships with builders deteriorate.

Self-Monitoring Strategy

Buy a crack width gauge (£5-10 online). Measure all cracks monthly. Record measurements in a spreadsheet with dates. This data shows whether cracks are static, growing slowly, or expanding rapidly.

Photograph cracks with a ruler showing scale. Include identifying features in each photo so you can match images to locations later. Date all photographs. Take shots from the same angle each time to enable direct comparison.

Note environmental conditions when checking cracks. Are you measuring in January cold or July heat? Moisture and temperature affect crack width. Cracks that open in winter and close in summer follow predictable thermal movement.

Moving Forward with Confidence

Most new build cracks are cosmetic. They look unsightly but don’t compromise structural integrity. Appropriate filling and redecorating resolves them permanently once settlement completes.

Genuine structural cracks remain rare in new builds. Modern building regulations, regular inspections, and warranty requirements mean serious defects affect only a small percentage of properties.

Trust your instincts anyway. If cracks seem excessive, demand proper investigation. Builders should welcome opportunities to prove their work meets standards. Reluctance to investigate suggests they already know problems exist.