Builder Won't Fix Defects in Poland? How to Send a Formal Demand Letter

You look at your flat and see it: badly mixed silicone sealant, a thick blotch of paint, cables left exposed, or worse — a crumbling wall that's coming apart at the seams. You ask the builder to put it right, and he either goes quiet or tells you flatly: "I'm not fixing anything, you'll pay for it as it stands."

This is exactly the situation where a formal demand letter — specifically a notice to change the manner of performance or remedy defects — is your strongest move. It doesn't have to be a demand for money straight away: you can first demand action. But if the builder digs in, a follow-up demand letter for the cost of substitute repairs is often the next step. This guide walks you through how to do it and what to include.

This guide is general legal information, not legal advice. How the rules apply depends on your individual circumstances — the contract, the evidence, and whether the matter is consumer, civil, or business-to-business. Where advice or representation is needed, the matter should be assessed by a qualified Polish lawyer. Twoja Sprawa helps you organise the documents for that assessment.

What gives you the right to send a demand letter — the legal basis

If you signed an umowa o dzieło (a specific-result contract — the Polish equivalent of a contract for a defined outcome, where the builder promises a concrete result, e.g. "renovate the living room"), you're entitled to have that work carried out properly and in line with the contract.

The Polish Civil Code is clear on this (Article 636 KC — Kodeks cywilny, the Polish Civil Code):

Where a contractor carries out work defectively or contrary to the contract, the client may call on the contractor to change the manner of performance and set a reasonable additional deadline. If that deadline passes without result, the client may:

• arrange for the correction themselves (i.e. instruct another contractor to fix it) and charge the cost to the original builder,
• withdraw from the contract and demand repayment of sums already paid,
• demand a reduction in price for the work carried out (where the work is otherwise usable).

⚠️ Important: The exact conditions for recovering costs "at the builder's expense" need confirming with a lawyer — it depends on the contract, the facts, and whether the matter is a consumer case (with broader protections) or a business-to-business one.

When to send the letter — the sequence of steps

Before heading to court, the sensible (and often expected) approach is to give the builder a fair chance to put things right. The sequence looks like this:

1. An informal request — verbally, by text, or by email — "Please could you fix X and Y by [date]." - Keep a record of this — it's evidence you tried the informal route first.

2. A formal notice to change the manner of performance (if the informal request didn't work). - In writing (email, recorded/signed-for post, text message, messaging app). - Specify precisely which defects and what steps you want the builder to take. - Set a deadline — at least a few days (per Article 636 KC's "reasonable deadline" standard). - Warn that if the deadline passes, you may instruct another contractor and bill the cost to them.

3. If the builder refuses or ignores the notice — you move on to a demand letter for payment (covering the cost of substitute repairs).

What the notice to change the manner of performance should contain

The notice doesn't have to follow a rigid format — it can be an email, a text message, even an entry in a messaging app, as long as it's clear and kept on record. To make it as strong as possible, though, it should include:

Essential elements:

• The date sent and the builder's details (name, address, phone number, NIP — Polish tax ID — if they trade as a company).
• Your own details (name, address, phone number).
• The contract details — date signed, scope of works (e.g. "Contract dated 1 April 2026 for the renovation of the kitchen").
• A description of the defects — be specific about what's wrong:
• ❌ Weak: "The renovation was done badly."
• ✅ Strong: "The tile grout hasn't been finished properly — the brickwork is visible between tiles, the grout is crumbling, and part of the brick is exposed on the west wall. This requires the whole wall to be redone."
• Photos / documentation — attach dated photos of the defects. This is key evidence.
• A call to act — "I am calling on you to remedy the defects listed above within 7 days of receiving this notice (by [date])."
• A warning — "Should the work not be completed within the deadline given, I will instruct another contractor to carry out the repair and will seek payment of the cost from you."
• A signature (if a letter) or clear confirmation of authenticity (e.g. login details, IP address on an email).

How and where to send it

Best (for evidential strength): - Recorded/signed-for post (to the builder's home address or registered business address). - Email with a read receipt requested, where the system supports it. - Text message — formally weaker, but timestamped and on record.

Weaker, but still useful: - Messenger / WhatsApp messages — harder to prove delivery, though the platform usually logs timestamps.

Always: - Keep a copy (a screenshot or printout) of whatever you send.

How to work out a reasonable deadline

Article 636 KC refers to a "reasonable deadline." In practice, that generally breaks down as:

• Minor defect (e.g. re-priming, a small crack) — 3–7 days.
• Moderate defect (e.g. redoing a wall, replacing a fitting) — 7–14 days.
• Complex defect (e.g. breaking through a wall, rewiring) — 14–30 days.

⚠️ The deadline must be objectively achievable. If you set two days for rebuilding an entire kitchen, a court may find that unreasonable — which weakens your position.

What happens once the deadline passes — substitute performance

If the builder: - doesn't respond to the notice at all, - responds but refuses to comply, - agrees but then does nothing,

you can then instruct another tradesperson to carry out the repair. Under Article 636 KC, this is known as "substitute performance" (wykonanie zastępcze).

Procedure:

1. Notify the builder in writing — "As you have not fulfilled your obligation, I am instructing another contractor to carry out the repair; the cost will be charged to you."
2. Instruct a qualified tradesperson — in writing, with a costed quote.
3. Gather your documents: - The invoice or receipt from the new contractor. - Before-and-after photos. - A handover report from the new contractor, if one is issued.
4. Send the bill to the original builder — "Pursuant to Article 636 of the Polish Civil Code, I enclose an invoice for the repair in the amount of [sum] PLN. I call on you to pay within 7 days."

⚠️ Important: The cost of the repair must be reasonable — you can't hire the most expensive specialist in the business purely to inflate the amount charged to the original builder. A court will assess whether the sum claimed is justified.

Mistakes to avoid

• Not documenting the defects — take photos or video of the defects BEFORE anything is fixed. Otherwise the builder can claim the defects never existed.
• A vague notice — "Sort it out" isn't enough. Describe exactly what's wrong and what needs to happen.
• No deadline set — a notice without a deadline may carry little weight; the builder can argue it was never clear when they were supposed to act.
• Relying on text messages with no backup copy — these can be hard to prove in court. Email or a letter is stronger.
• Arranging repairs yourself without sending a notice first — if you fix things yourself before giving formal notice, it's much harder to recover the cost from the original builder.
• Editing the notice after sending it — send one clean, final version. Don't add notes or amendments afterwards.

Documents to gather before starting a claim

If the matter goes to court, prepare:

• The contract (or a copy — even a text message setting out the terms counts).
• The notices sent (copies of emails, screenshots, printouts of the notice to remedy defects).
• Dated photos of the defects.
• Any instructions/agreements with the replacement contractor, if you arranged repairs.
• Invoices for the repair and proof of payment.
• All correspondence with the builder (emails, texts, messages).
• Witnesses — did anyone else see the defects? Names and contact details.
• An independent expert's opinion (optional, but it strengthens the case) — a court may also appoint its own expert.

When it's time to bring in a lawyer

Get the matter reviewed by a specialist if:

• The sum involved is significant (above roughly 5,000–10,000 PLN).
• The defects are serious (they affect structural safety).
• The builder trades as a registered company — the matter may fall under "business dispute" procedures, which follow a different court process.
• You lack clear documentation (e.g. the contract was only ever verbal).
• The builder threatens a counterclaim against you (e.g. alleging your demands are "unjustified").

Common mistakes people make

• Sending a notice without specifying the defects clearly — a court may doubt whether they genuinely existed.
• Failing to document verbal conversations — if you can't show you asked verbally for the work to be fixed, it's harder to prove neglect.
• Signing off on a handover report that says "no objections" — if you signed a document confirming acceptance without reservations, this can work against you later. Always note any issues on the handover document itself.
• Arranging a repair without sending a prior notice — every step should be documented.
• Confusing a "demand for payment" with a "notice to act" — first call on the builder to fix the defects; only if they don't, move on to demanding payment for the repair.

Frequently asked questions

Do I have to send a notice before going to court?

Formally, no — you can bring a claim straight away. But courts generally look favourably on evidence that you tried to resolve the dispute amicably first. If you can show you gave notice and nothing happened, a judge is likely to view your case more favourably. It's also often faster than going through the courts — sometimes the builder comes round once they receive a formal notice.

Is email enough, or do I need recorded post?

Email with a read receipt is a good starting point. But if the builder claims they never received it (server issues, spam filters), recorded/signed-for post is safer. Ideally, send both.

What if the builder refuses to collect the recorded letter?

The postal service will usually attempt delivery more than once. If it's ultimately undeliverable, it will be returned to you with a note to that effect. At that point you can rely on email or text as an alternative. Proof that delivery was attempted also counts in your favour.

Can I hire the most expensive tradesperson to run up the bill against the builder?

No. The cost of the repair must be justified by market rates. A court will check whether the sum is reasonable — if you pay 10,000 PLN for work that would normally cost 2,000 PLN, the court is likely to award you only the 2,000 PLN. Keep costs proportionate.

Does the right to send a notice expire?

The notice itself doesn't "expire" as such. But the underlying claim is subject to a limitation period. For a specific-result contract (umowa o dzieło), this is 2 years from the date the work was handed over (Article 646 KC). So if you spend six months on the notice stage, you'd still have roughly 18 months left to bring a claim. That said, don't delay unnecessarily — every day that passes works against you (evidence stays fresher the sooner you act).

Summary and checklist

Before sending the notice:

• ☐ Do you have the contract (or a text message/note recording the terms)?
• ☐ Have you taken dated photos or video of the defects?
• ☐ Have you kept records of your attempts to communicate (emails, texts)?
• ☐ Do you know the builder's exact address (home or registered business)?
• ☐ Do you have their NIP (tax ID), if they're a company — this makes delivery easier?

What the notice should contain:

• ☐ Date and the builder's details.
• ☐ A specific description of the defects (no vague generalities).
• ☐ A deadline for the repair (at least a few days; longer for more complex work).
• ☐ A warning of consequences (substitute performance, a claim for payment).
• ☐ Photos/documentation of the defects (attached).

After sending:

• ☐ Do you have a copy of the notice you sent?
• ☐ If by email — did you request a read receipt?
• ☐ If by post — do you have proof of delivery from the postal service?

Content last reviewed: 26 June 2026.

Related articles:

• Builder did a bad job on your renovation? Where to start with a complaint
• Defects after a renovation — photos, expert opinion and cost estimates as evidence
• Builder took a deposit and never finished the renovation — what can you do?