Contingency for building a house: how much and hidden extras

Hold 7–10% of the contract price on top of the estimate for a house build. That money pays for your own decisions during construction: a different tile, extra sockets, a partition moved. Every other extra that appears inside a build comes from the estimate itself, when quantities are understated, work is left out, a material is listed as "to be agreed" or the price is not fixed in lari. Each of these has a contract term that closes it. Costs outside the contract (the plot, utilities, furniture) are covered in the article on what a house estimate does not include.

How much contingency should you add to a house construction estimate?

We recommend 7–10% of the contract price. A 200 m² full-cycle house at 1,250–1,550 ₾/m² costs 250,000–310,000 ₾, so its reserve comes to 17,500–31,000 ₾. The reserve is not part of the estimate and is not paid to the contractor in advance: it is your money, waiting for the first decision you make on site.

The lower end is usually enough if the design, materials and finishes are chosen before you sign. Keep closer to 10% if you deliberately leave some decisions for later, such as the tile layout, sanitaryware or lighting. We advise against spending the reserve at the start, even if it looks like more than you need.

Where do extras come from once the estimate is signed?

An extra inside a build almost always has one of six causes. The first five depend on how the estimate and the contract are written; the sixth depends on you.

• Quantities in the estimate are lower than in the design: concrete volume, plaster area or cable runs were understated, and the gap shows up when the material runs out before the work does.
• Work the house cannot be built without is missing from the estimate: spoil removal, formwork, scaffolding, waterproofing, rough materials, first-fix services for the finishes. The bill arrives when the excavation is already dug and changing contractor is hard.
• A material is listed as "to be agreed". Without a concrete grade, rebar class or insulation type the item stays open, and its price is named when it is time to buy.
• The price is tied to the exchange rate or a supplier’s price list. If the estimate is not fixed in lari, a rise in rebar or concrete prices can land on the client.
• Part of the quantity is measured as built. Nobody knows the depth of a borehole on the plot in advance, for example. That is fine as long as the estimate shows a unit rate rather than an empty line.
• You change a decision mid-build: move a partition, add underfloor heating upstairs, pick a more expensive tile. This is what the reserve is for.

How does a fixed estimate rule out hidden extras?

When we build a house, the design is included in its price, so we price the estimate from the drawings, not from similar houses. It is split into sections (earthworks, foundation, walls, roof, engineering, finishes), each with quantities, unit rates and material costs. In the contract the estimate is fixed in lari and never re-quoted on the exchange rate.

A contractor cannot revise the estimate on its own initiative. If we missed some work through our own error, that is our responsibility, not a reason to charge you more. Surveys and the building permit (3,000–9,000 ₾) are not in the price per m², but we list them as a separate line before signing, so they do not surface mid-build. This is how turnkey house construction works: one contract, one estimate and one warranty for the whole chain. Prices per m² by stage are on the construction prices page.

How are changes handled during the build?

Every change is formalised as a variation order before the work starts and only after your written confirmation. The order states what changes, what it costs and whether the deadline moves. It cannot appear without your signature, so the contract sum does not grow after the fact.

You pay for changes from the reserve. Most often they are a material swap, extra sockets, a different tile layout or moving a non-load-bearing partition. If a change affects the structure, the design is revised first and the build follows.

How does the payment schedule protect you from extras?

The advance is no more than 15%; after that you pay for accepted stages against signed acceptance reports. We hand over hidden work (reinforcement, waterproofing, services routing) with an acceptance report and photos before it is covered up. Your money goes against work that is done and accepted.

The contract sets a penalty for delays caused by us. The warranty under the contract is 10 years on the structure, 5 years on the roof and facade, 3 years on engineering systems and 2 years on finishes.

How do you check another contractor’s estimate for hidden extras?

Before signing, go through the estimate with this list:

• The estimate is itemised with quantities and unit rates, not one sum per m².
• Quantities of concrete, masonry, plaster and cable match the design.
• Concrete grade, rebar class, waterproofing and insulation types are named; there are no "material to be agreed" lines.
• Earthworks and spoil removal, formwork, scaffolding, waterproofing, subfloors and first-fix services are all there.
• Items measured as built are listed separately, each with a unit rate.
• The contract says the price is in lari and is not re-quoted on the exchange rate, and that changes go only through a written variation order.

If the figure is well below other offers, the reason is usually what the estimate leaves out; see why one estimate is cheaper than another. We can review another contractor’s estimate: an estimate audit gives a written report with the omitted items and an assessment of what the house will really cost, and its fee is credited if you sign a construction contract with us. If the build is already under way, technical supervision checks quantities and hidden work on site.

What can the reserve be spent on, and what not?

On your decisions: a different material, extra points, a changed layout. Errors in the contractor’s estimate are not paid from the reserve; whoever priced the work fixes them.

Do you need a reserve if the estimate is fixed?

Yes. A fixed estimate protects the agreed scope of work. Anything you decide to add or change after signing is outside it and is paid under a separate variation order.

What should you do if the contractor already asks for more money?

Ask for the calculation in writing: item, quantity, unit rate. Check it against the estimate. If the item was in the estimate, there is nothing extra to pay; if it was not, find out whether the contractor could have foreseen it from the design. If the contractor has left the site, see how to finish a house after another contractor.

Want an estimate with no open items? Send the design or the plot address: we will price the house section by section, fix the price in lari and list everything on top of it as a separate line. Get an estimate.