Prime Cost vs Provisional Sum

What Homeowners Should Understand Before Signing a Building Contract

When reviewing a renovation quote, two terms appear again and again — and most homeowners aren’t fully confident about what they mean:

Prime Cost (PC) items
and
Provisional Sums (PS)

They may sound similar.
They are not.

Understanding the difference can significantly affect your final budget.

What Is a Prime Cost (PC) Item?

A Prime Cost item is an allowance for a product that hasn’t yet been selected when the quote is prepared.

These are typically fixtures and fittings.

Common examples include:

• Tapware

• Toilets

• Appliances

• Tiles

• Door hardware

• Basins and baths

The builder includes a monetary allowance for each item.

If you later choose a product that costs more than the allowance, you pay the difference (usually plus the builder’s margin).
If you choose something that costs less, you receive a credit.

Key point:
Prime Cost items relate to products you will personally select.

What Is a Provisional Sum (PS)?

A Provisional Sum is an allowance for work that cannot be accurately priced at the time the contract is prepared.

It usually relates to labour and construction where the scope is still uncertain.

Common examples include:

• Excavation where ground conditions are unknown

• Structural work pending engineering

• Service relocations

• Complex demolition

• Drainage modifications

The builder includes an estimated amount based on likely conditions.

If the work costs more than the estimate, you pay the difference.
If it costs less, you receive a credit.

Key point:
Provisional Sums relate to uncertain construction work — not product selection.

Why This Matters

Two renovation quotes can differ by tens of thousands of dollars because:

• One builder includes higher Prime Cost allowances

• One builder includes larger Provisional Sums

• One builder prices conservatively to protect against risk

• Another prices leaner, allowing variations to occur later

You may think you’re comparing builders.

Often, you’re comparing risk strategies.

How to Reduce Budget Surprises

The more decisions resolved before pricing:

• Layout finalised

• Joinery detailed

• Finishes selected

• Engineering confirmed

The fewer allowances are required.

Fewer allowances mean:

• Greater price accuracy

• Fewer variations

• More control during construction

• Less financial stress

Clear documentation protects both the homeowner and the builder.

Final Thought

Prime Cost items and Provisional Sums are not red flags.
They are normal components of construction contracts.

But the fewer unknowns in your project, the more accurate your quote will be.

Clarity before construction is one of the most powerful cost-control tools available in any renovation.