How to Build a Rehab Contingency Without Hiding Scope Gaps

Direct answer

A rehab contingency should reserve money for real uncertainty, not compensate for an incomplete scope that should have been defined before award.

Use contingency for conditions you cannot reasonably verify yet, such as concealed damage discovered after demolition. Do not use it as a catch-all for missing quantities, undecided base work, unreviewed inspection findings, or contractor exclusions that should already be visible.

The best contingency is therefore tied to an uncertainty register, not just a percentage added to the bottom of a spreadsheet.

Start by separating four different things

Before deciding what belongs in contingency, divide the budget into:

1. Known base scope

Work you already know needs to be performed and can reasonably define.

Examples:

• replace damaged flooring;
• paint defined areas;
• replace broken fixtures;
• repair confirmed drywall damage;
• replace a failed water heater after appropriate assessment.

This belongs in the base scope, not contingency.

2. Allowances

Known categories where the exact selection or final amount is still pending.

Examples:

• flooring material selection;
• vanity selection;
• decorative lighting package.

See: Allowances vs. Selections in a Rehab Budget.

3. Alternates

Optional scope choices.

Examples:

• refinish cabinets vs. replace cabinets;
• patch roof vs. full replacement where both are valid options under consideration.

These should be priced separately rather than buried in contingency.

4. Uncertainty / contingency

Conditions that may create additional cost but cannot yet be fully resolved without opening, testing, specialist review, or another defined trigger.

Examples:

• concealed subfloor damage;
• wall damage behind removed cabinets;
• hidden plumbing deterioration;
• unknown extent of moisture damage after finishes are removed.

That is where contingency belongs.

Build an uncertainty register

Instead of writing “10% contingency” and moving on, document each meaningful uncertainty.

This gives the contingency a reason to exist.

Contingency is not a substitute for diligence

Before reserving money for a condition, ask:

• Can the condition be inspected now?
• Can a specialist review it before closing or before contract award?
• Can photos/video resolve it?
• Can a targeted exploratory opening resolve it where appropriate and authorized?
• Is there a known quantity that should simply be measured?
• Is the issue actually an allowance or alternate instead?

If the answer is yes, resolving the uncertainty may be better than carrying a blind reserve.

See: What Property Problems Need Specialist Review Before You Buy? and Photos, Video, Inspection, or Site Visit: What Evidence Is Enough?

Do not use a percentage as a prediction

A percentage contingency can be a useful portfolio or budget-control tool, but it is not evidence that hidden conditions will cost that amount.

Avoid language like:

“A 10% contingency is enough for this rehab.”

without project-specific support.

A better statement is:

“The project has identified uncertainty in these areas. The owner is reserving a contingency amount as a risk buffer, while each actual change still requires documentation and approval.”

The reserve is financial capacity. It is not automatic authorization to spend.

Tie contingency release to documented changes

Contingency should not become a contractor slush fund.

A sound process is:

1. condition is revealed;
2. contractor documents the condition;
3. scope impact is defined;
4. price and schedule impact are stated where practical;
5. owner or authorized manager approves the change;
6. contingency budget is reduced by the approved amount;
7. updated scope and project history are preserved.

See: Change Orders on Investment Property Rehabs.

Separate owner reserve from contractor proposal

An investor may maintain a contingency reserve even if the contractor's proposal contains no contingency line.

That can be cleaner because:

• the owner retains control of uncommitted funds;
• base contract price remains tied to known scope;
• additional work must be justified;
• remaining contingency is not automatically spent.

If a contractor does include contingency or unit-price provisions, understand exactly how unused amounts are treated.

Use unit prices when uncertainty is measurable

Some unknowns can be handled better with pre-agreed unit pricing than with a vague allowance.

Example:

Base scope includes 32 square feet of subfloor replacement. Additional verified replacement beyond that quantity, if required after finish removal, to be priced at an agreed unit rate subject to documentation and owner authorization.

This can reduce negotiation after demolition, provided the unit definition is clear and the work is appropriate for unit pricing.

Use not-to-exceed structures carefully

For uncertain work, a not-to-exceed amount can define a decision boundary.

Example:

Contractor may investigate and perform localized corrective work up to the approved limit only after documenting the condition. Work expected to exceed the limit requires additional authorization before proceeding unless immediate action is necessary to prevent damage or address an urgent safety condition.

The key is still scope, evidence, and authority—not just the cap.

Distinguish contingency from deferred work

If an investor intentionally decides not to perform a repair now, that is not contingency.

It is deferred scope and should be recorded as such.

Example:

• exterior repaint deferred 12 months;
• aging water heater monitored, not replaced;
• cosmetic bedroom flooring deferred until turnover.

Deferred work should remain visible in property history so it does not vanish from future decisions.

See: Repair Now, Defer, or Monitor? Prioritizing Investment Property Work.

Watch for contingency double counting

A budget can accidentally reserve for the same risk multiple times.

Example:

• contractor includes an unknown-condition allowance;
• estimator adds a line-item reserve;
• owner also adds a blanket percentage contingency.

That may be intentional, but it may also overstate the reserve.

Map each reserve to the risk it is intended to cover.

Contingency should shrink as uncertainty shrinks

As a project moves from acquisition diligence to scoped rehab to active demolition, uncertainty changes.

A good budget is dynamic:

early diligence: broader unresolved condition set pre-award: more conditions investigated and scoped after demolition: concealed conditions become known mid-project: approved changes replace estimates closeout: unused contingency remains unspent

Do not keep old uncertainty assumptions after better evidence exists.

Practical contingency worksheet

For each uncertainty, record:

• condition;
• evidence available;
• confidence level;
• next evidence step;
• trigger date/event;
• base-scope assumption;
• financial reserve assigned, if any;
• authority required to spend;
• resolution status;
• final actual impact.

This becomes more valuable than a single percentage because it explains why the reserve existed and what happened to it.

How OttoServ fits

OttoServ can connect uncertainty to the rest of the project rather than treating contingency as an isolated spreadsheet line.

The intended workflow is:

observed condition → uncertainty register → evidence plan → base assumption → reserve → trigger → documented change → approval → updated scope → property history

That allows the investor to preserve the distinction between what was known, what was assumed, and what changed.

FAQ

What percentage contingency should I use?

There is no universal percentage that is correct for every rehab. The amount should reflect the actual uncertainty in the property and project. A percentage can be a reserve policy, but it should not replace condition-specific analysis.

Is contingency part of the contractor's price?

Not necessarily. An owner may hold contingency outside the contractor's base contract and release it only for approved additional work.

Is an allowance the same as contingency?

No. An allowance generally covers a known category with an unresolved selection or quantity. Contingency reserves for uncertainty that is not part of known base scope.

Should hidden damage automatically come out of contingency?

Only after the condition and scope impact are documented and approved under the project's change process.

What happens to unused contingency?

If it is truly an owner reserve, unused funds remain unspent. Contract-specific treatment can vary, so the agreement should be clear.