What if defects appear in a rental building and increase costs beyond budget?
Published 5 November 2026
If defects emerge in a residential block that push costs above budget, they are managed through classification of findings, recalculation of economics before moving to the next phase, and use of contractual tools. Most defects are revealed during the audit; latent defects may emerge during construction. Therefore, it is important to have a budget reserve and a project divided into phases with control points.
Summary
- Most defects are uncovered during the audit; the remainder emerge when structures are exposed during construction and during testing.
- Distinguish between foreseeable findings (building age, normal wear and tear) and latent defects that could not be identified in advance.
- A work contract, a budget reserve, and a process for approving changes are the key tools for cost control.
- When budget is exceeded, prioritise spending: first safety and legal requirements, then elements that affect unit marketability.
- Proceed to the next project phase only with confirmed figures.
When defects most commonly emerge
Defects emerge at three points in the project: during the audit, during construction, and during testing and handover. The sooner they come to light, the more cost-effectively they can be addressed.
- Audit and preparation: inspection, documentation review, assessment of building condition, building services and legal status. Most visible problems are caught here.
- Construction: once floors, ceilings or building services are uncovered, damaged timber, dampness or non-compliant installations that were not visible during inspection may be revealed.
- Testing and handover: inspections, building services tests or compliance checks can identify repairs needed before completion.
The permitting of building alterations is governed by the Building Act (Act No. 283/2021), so some documentation requirements may only emerge during its preparation.
Foreseeable and latent defects
The key distinction is whether the defect could have been identified during proper preparation, as this determines responsibility and financing approach.
| Type | Examples | How to address |
|---|---|---|
| Foreseeable | worn building services, old roof, visible dampness on masonry | include in budget and reserve during audit |
| Latent | damaged load-bearing element under plasterwork, undocumented alteration from previous period | reserve, trial digs before work begins, change process in contract |
| Legal | mismatch between actual condition and documentation, easements on the property | check during legal review before investment |
An older building always carries uncertainty. The aim is not to eliminate it, but to value it and mitigate it through trial digs and reserves.
Maintaining budget control
Control is provided by a phased approach with confirmed figures at each step. The project passes through three stage gates: legal, permit and sales. The next phase is only entered with confirmed figures, so surprises do not accumulate.
- Commission an audit with structural and legal assessment. The Audit and plan is completed within 6 weeks.
- Include a reserve in the budget proportionate to the building's age and condition; determine its size on the basis of the audit.
- Before work begins, carry out trial digs in the highest-risk areas.
- Require an itemised budget and regular invoicing.
- Approve each change in writing with impact on price and schedule.
The full process is described on the How it works page.
Contractual tools under the Czech Civil Code
A work contract determines who bears the risk of price overrun and how additional work is handled. The basis is regulated by the Czech Civil Code (Act No. 89/2012) in the provisions on work contracts.
- Price: fixed price or price according to budget. Terms for price increases should be clearly specified.
- Additional work: agree that it is only carried out on the basis of written approval.
- Defects in work: rights arising from defective performance and warranty period, which can be modified by contract.
- Contractual penalties and holdback: retention of part of the price until defects are remedied.
- Hidden obstacles: determine who bears the costs of discovering and removing unforeseen obstacles.
The specific wording of the contract should be reviewed by a lawyer, particularly regarding fixed price and risk allocation.
Financing overruns and prioritisation
When budget is exceeded, expenditure is ranked by urgency and impact on unit marketability.
- Safety and mandatory requirements: structural integrity, fire safety, building services that affect operation.
- Conditions for permitting and transfer: everything required for compliance with the Building Act (Act No. 283/2021) and creation of units.
- Elements affecting price: common areas, entrances, unit condition with greatest impact on sales.
- Deferrable improvements: cosmetic and supplementary works that can be carried out later or left to purchasers.
Funding can come from the reserve, own capital, loan, or cost-sharing with a partner under a partnership / JV arrangement. The typical value difference between selling a building as a whole and selling units separately is +20–40%; the exact figure is determined by feasibility analysis. After each cost increase, therefore recalculate whether the project still makes economic sense. You can make a rough estimate in our potential calculator.
What to do now
First verify the actual condition of the building and only then commit to a budget.
- Prepare building documentation, an extract from the Czech Land Registry, a summary of repairs and tenancy agreements.
- List known defects and locations where you suspect a problem.
- Consider an audit and plan, which will confirm the condition and figures.
- If you want both preparation and execution under one contract, look at our End-to-end implementation.
You can obtain a non-binding offer or building assessment via the form below the article.