Why Can a House on Stumps Become Uneven, and What Else Needs Checking?
Owners, builders and restumping clients
An uneven suspended timber floor can involve changing ground support, timber shrinkage or deterioration, or a combination. The slope alone does not identify which. Its stumps and connections also have jobs beyond keeping the floor level, including resistance to uplift or sideways forces where applicable.
To discuss measurement of uneven floors and possible movement, explore our floor level surveys. An article cannot determine the cause or appropriate solution for an individual property.
Ground movement is not the only explanation
Timber shrinkage and biodegradation can influence subfloor settlement. Differing internal and external support and drying beneath a ventilated subfloor also need consideration. Those are alternative questions to investigate, not a diagnosis from the floor's shape.
Keep dates, room locations, door or skirting symptoms, known subfloor water and available timber/support inspection records. Ask whether the professional has assessed the floor structure as well as the ground. Relevant subfloor ponding also needs assessment, but reducing ventilation to try to control soil drying is not a homeowner remedy.
Braced and bracing are not interchangeable
A braced stump forms part of a diagonal-bracing arrangement; a bracing stump also resists a horizontal load applied above ground level. Design provisions for braced stumps should not simply be applied to bracing stumps.
That distinction matters when a quotation simply says new stumps. Ask the designer which members carry the floor or roof, which form part of the lateral-resisting system and which connections transfer those actions. A generic pad-size detail cannot answer all those questions.
A pad spreads load into particular ground
Vertical gravity capacity depends on footing area and assessed bearing capacity. Uplift and horizontal resistance also depend on the backfill and support configuration. Soil, member, connection and load assumptions remain part of the design; the article deliberately does not reproduce a pad-sizing or capacity schedule.
Loose sand also requires particular consideration in that braced-stump context. A nearby firm surface or the appearance of a concrete collar is not evidence of the complete below-ground arrangement.
A restumping project changes connections as well as levels
Before work, keep existing reports, condition photographs and the agreed re-levelling scope. Ask how the new support and bracing arrangement will be checked and what completed-work information will be provided. Different support or ground conditions encountered during work need an authorised design response, not an unrecorded substitution.
An alignment tolerance and a footing capacity are different assessments. A plumb stump can still have a connection or foundation issue; a tilted member needs its context assessed rather than an automatic owner adjustment.
What an owner should not attempt
Do not jack the house, remove bracing, dig out a pad or adjust a stump to test a theory. Give accessible observations and records to the appointed professionals. A floor that drops suddenly, feels unstable or shows apparent support loss needs prompt professional help and avoidance of the affected area, not a longer monitoring period.