Reviewing a building quote — the complete guide for project owners

A quote review is a systematic check of a construction quote for completeness of content, correct pricing and contractual risks. The aim: identify hidden costs, unclear specifications and variation risks before awarding the contract. The result is a written review report with specific guidance on what should be negotiated or improved.

Key points at a glance

• An average of 31 defects per construction project according to the BSB/IFB study 2025, based on 700 quality inspections.¹
• Average damage costs of 84.000 euros per new build due to construction defects (BSB 2018).²
• A professional review from 79 euros saves many times that amount in variation costs on average.
• Regional construction costs vary by up to 53 % between German states (LBS 2025).⁴

Why should you have your construction quote reviewed?

In a long-term study involving 700 quality inspections in 2025, the Bauherren-Schutzbund (BSB) found an average of 31 defects per construction project , including 25 during construction and 6 at final acceptance (BSB/IFB, 2025).¹ Many of these defects can be traced back to unclear or incomplete quotes. A professionally reviewed quote is the simplest way to identify such problems early.

What does this mean financially? Average damage costs per new build amount to 84.000 euros and have therefore increased by 89 % since 2006 (BSB/IFB, 2018).² Across the industry, construction error costs total around 13 billion euros per year (BauInfoConsult, 2022).³

Furthermore, the Federation of German Consumer Organisations (vzbv) has brought legal action against 24 unfavourable clauses in construction contracts. Entire houses are described on three pages, leaving project owners unable to see what is missing (vzbv).⁵

The most common risks in unchecked quotes:

• Variations: Missing or vaguely described work leads contractors to claim additional costs during execution.
• Incomplete specifications: If the work included in the price is not precisely defined, disputes arise over the scope.
• Excessive unit prices: Some items are priced well above the market rate, without non-specialists being able to recognise this.
• Missing contractual clauses: Defects liability periods, payment schedules or liability provisions are missing or unfavourably worded.

A review before awarding the contract gives you the opportunity to identify weaknesses and renegotiate. Spot specific warning signs in a quote with our guide 7 warning signs of overpriced contractors' quotes.

Which 6 areas does a quote review cover?

According to an LBS survey, construction costs in Germany vary regionally by up to 53 %, ranging from 1.983 to 3.029 euros per square metre (LBS Research, 2025).⁴ Looking at the total price alone is therefore insufficient. A thorough review covers six areas.

1. Specification

The specification is the heart of a construction quote. It defines exactly what will be done. Ensure every item is clearly worded: which material is used? Which area will be worked on? What quality is agreed? VOB/C's general technical contractual conditions define the information required in a proper specification for each trade.⁶

Wording such as “painting as required” or “electrical installation lump sum” is a warning sign. Such vague descriptions give the contractor scope over execution and price. When a lump sum makes sense and when it does notis explained in a separate guide. If you are unsure whether you actually have a binding quote or merely a non-binding estimate, find the distinction in our guide Estimate vs. quote.

2. Price plausibility

Are the unit prices understandable? A square metre of external wall insulation (ETICS, 14 cm, EPS) costs between 120 and 200 euros depending on region and specification. If the quote lists 250 euros, ask questions. If it lists 60 euros, that may indicate inferior materials or missing work components.

An important point: construction prices recently rose by 3,2 % year on year , with peaks of 5,4 % for electrical and timber work (Destatis, November 2025).⁷ Compare unit prices against current reference values rather than outdated tables. Find more current prices in our Guide to external wall insulation costs 2026.

3. Contractual clauses

Alongside prices, a good quote also contains contractual provisions. Check that the following points are clearly regulated:

• Defects liability period (statutory: 5 years under BGB § 634a, 4 years under VOB/B § 13)⁸
• Payment schedule with specific milestones
• Rules for additional costs and variations
• Acceptance record and procedure for defects
• Contractor's proof of insurance

If these clauses are missing, your position in a dispute is weaker. This sounds obvious, but it is not: the VPB found that around 75 % of all payment schedules do not match actual construction progress (VPB/baulinks.de).⁹ Advance payments exceeding 30 % without security are not customary in the industry. Read here about what matters when reviewing construction contracts in detail.

4. Completeness

A common problem: the quote includes only some of the necessary work. A bathroom refurbishment, for example, may omit waterproofing beneath the tiles, which is mandatory under DIN 18534.¹⁰ External wall insulation may omit connection work around windows and doors. What does this cost? Missing items are almost always billed later as variations. How to specifically avoid variation costs is explained in a separate guide.

5. Quantity check

Do the stated quantities match actual conditions? If your living room measures 28 square metres but the quote allows 35 square metres for flooring, you are overpaying. Conversely, quantities set too low can lead to subsequent claims.

Be particularly careful with lump-sum quotes: no quantities are given, making verification harder. Ask for a breakdown in this case.

6. Variation risks

Variations arise when work was not included in the original quote but is necessary for completion. Typical risk areas:

• Unclear distinction between included and excluded work
• No rules for unexpected findings (e.g. asbestos, damp masonry)
• Lump-sum items without a clearly defined scope
• No information on disposal costs, scaffolding or site setup

The more of these points remain open, the greater the risk that final costs significantly exceed the quoted price.

How can you check a construction quote yourself? 7-point checklist

In their reviews, VPB experts identified an average of 10.000 euros in defects before contracts were signed (VPB/baulinks.de).⁹ You do not need to be an expert to find the most obvious problems yourself. These seven points will help.

1. Read each work item individually: Do you understand every item? Is it clear what will be done, with which materials and to what extent? Mark everything that is unclear or described as a lump sum.
2. Compare quantities with your own measurements: Check areas, lengths and item counts wherever possible. Compare the quote's figures against your own measurements or building drawings.
3. Research unit prices: Look for comparison prices for the largest items. A second quote or our Guide to renovation costs 2026 provides a benchmark.
4. Look out for missing trades: Consider all the work your project requires. Ancillary works such as site setup, disposal or protective measures are frequently missing.
5. Check the payment schedule: How much is payable and when? A reputable payment schedule follows construction progress. Advance payments exceeding 30 % without security are a warning sign.
6. Check defects liability and liability: Does the quote state a defects liability period? Does it refer to VOB/B or BGB? If neither is present, clarify this before signing. More in our Guide to defects liability in construction.
7. Assess the overall impression: Is the quote clearly structured? Are contact people and contact details provided? A professionally prepared quote suggests a business that works in an organised way.

Note: If you are unsure about more than two items, a professional review is worthwhile. The VPB recommends always having construction contracts independently reviewed before signing, as even experienced project owners overlook typical contractual traps.

How much does a professional quote review cost?

Construction error costs in 2022 amounted to around 13 billion euros across Germany, equivalent to around 8 % of industry turnover (BauInfoConsult/haustec.de, 2022).³ Against this backdrop, the costs of a professional review are modest. Here are the common options:

For comparison: a renovation contract worth 40.000 euros may generate variations of 4.000 to 8.000 euros if the quote is not reviewed. A review for 79 to 99 euros is a modest investment by comparison. If you obtain several quotes, also read our guide to comparing contractors' quotes.

Which provider suits your project?

A Hertie School study shows that public construction projects cost an average of 73 % more than planned, with buildings still costing 44 % more (Hertie School of Governance, 2015).¹¹ Private construction projects are not exempt. Choosing the right review is therefore all the more important.

The right choice depends on your project, budget and schedule. For most renovations up to 100.000 euros, a digital review is a good first step. For major projects or legal uncertainties, an on-site surveyor may be the better choice. Find a detailed comparison in our article Online quote review vs. independent surveyor.

Frequently asked questions about quote reviews

What exactly is checked during a quote review?

A professional quote review examines all quoted items for completeness of content, price reasonableness and contractual risks. This includes the specification, unit prices, quantities, contractual clauses and potential variation risks. The result is a review report with specific observations and recommended actions.

Can I check a construction quote myself?

In principle, yes. The 7-point checklist above lets you check the most important aspects yourself. However, non-specialists often lack the experience to reliably identify excessive prices or missing work. A professional assessment is particularly worthwhile for contracts exceeding 10.000 euros.

How long does a professional review take?

That depends on the provider. A Cleverbauen24 Basic review takes 3 to 4 working days; the Express review takes only 24 hours. For an on-site surveyor, allow 2 to 4 weeks, while consumer advice centres often have waiting times of 1 to 3 weeks.

Is a review worthwhile for small contracts too?

For contracts under 5.000 euros, checking it yourself using the checklist is often sufficient. A free Quickcheck can provide additional guidance. From around 10.000 euros, a professional review is almost always worthwhile because potential savings significantly exceed the review fee.

When should I have the quote reviewed?

As early as possible, and always before signing. Ideally, have the quote reviewed as soon as you receive it from the contractor. This leaves enough time for questions or to renegotiate the price.

Does this also apply to individual trades?

Yes. The same review areas apply to quotes from individual trades such as electricians, decorators or floor layers. This is precisely where non-specialists often lack comparison values. For example, what a bathroom refurbishment or an electrical renewal in an older building should cost can be found in our cost guides.

Sources

1. BSB / IFB (Institute for Building Research): long-term construction quality study, 700 quality inspections across 100 construction projects, 2020–2024. Published May 2025.
2. BSB / IFB: construction damage and damage costs, based on AIA AG insurance data, November 2018.
3. BauInfoConsult: German construction industry error cost balance 2022, around 13 billion euros (approx. 8 % of industry turnover). Reported via haustec.de.
4. LBS Research: residential property market 2025, regional construction cost differences (1.983 to 3.029 euros/sqm).
5. Federation of German Consumer Organisations (vzbv): legal action against 24 unfavourable clauses in construction contracts and specifications.
6. VOB/C – General Technical Contractual Conditions for Construction Work (DIN 18299 ff.).
7. Federal Statistical Office (Destatis): residential construction prices, November 2025 (+3,2 % year on year). Press release PD26/011, January 2026.
8. § 634a BGB – limitation of defects claims; VOB/B § 13 – defects claims.
9. VPB: analysis of construction contracts and payment schedules, reported via baulinks.de, 2005.
10. DIN 18534 – waterproofing of internal spaces.
11. Hertie School of Governance (Prof. Dr Genia Kostka): study of major public projects, 170 projects from 1960–2014, averaging 73 % above planned costs.