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Hiring the wrong building contractor is one of the most expensive mistakes a Dublin homeowner can make. The right questions, asked before you sign anything, are how you tell a competent contractor from a risky one. This guide covers the ten questions to ask, what a good answer sounds like, and the specific things to check for yourself.
Building work shapes the comfort, safety and value of your home, whether it is an extension, a full renovation or a new build. Spending ten minutes on the right questions is the cheapest insurance you will ever buy.
Why The Right Questions Matter
A contractor’s answers tell you three things a glossy brochure cannot: whether they are competent, whether they are compliant, and whether they communicate clearly. Most projects that go wrong show warning signs at the quoting stage, vague pricing, no written contract, reluctance to show insurance. Asking direct questions early is how you catch those signs while you can still walk away.
For the flip side of this guide, the specific warning signs that a contractor is best avoided, see our guide to the red flags to watch for when hiring a Dublin builder.
The 10 Questions To Ask Before Hiring A Building Contractor
1. Are you registered with CIRI?
The Construction Industry Register Ireland (CIRI) is the statutory, government-backed register of competent builders, established under the Regulation of Providers of Building Works Act 2022. Registration is being rolled out on a phased basis from 2026, starting with residential builders. A registered contractor has demonstrated competence, is tax compliant and carries the required insurance. You can search the register yourself at ciri.ie. Note that because the rollout is phased, some genuine smaller contractors may not appear yet, in which case look for Construction Industry Federation membership or a Voluntary Construction Register listing. A flat refusal to discuss credentials is the answer you do not want.
2. What insurance do you carry?
A contractor should hold public liability insurance, which covers damage to your property and neighbouring properties, and employers liability insurance, which covers anyone working on site. For most domestic projects, look for public liability cover of at least €2 million, and €6 million or more on larger jobs. Ask to see current certificates, not copies from two years ago, and for structural work ask about contract works (all-risks) cover. A good answer comes with paperwork. A vague answer (“we’re fully covered, don’t worry”) is not enough.
3. Can I see examples of similar projects, and speak to recent clients?
Experience on a job like yours matters more than years in business generally. Ask for at least three recent projects of similar type and scale, ideally completed in the last two years in Dublin or the surrounding counties. Ask to speak to those clients directly. A confident contractor will have no problem with this. Hesitation, or references who are always “away at the moment”, tells you what you need to know.
4. Will the work be done by qualified tradespeople?
A general contractor coordinates specialist trades, and some of those trades are legally regulated in Ireland. Electrical work should be carried out by a Safe Electric registered electrician. Any work on gas must be done by an installer registered with the Register of Gas Installers of Ireland (RGII). Ask who will carry out these elements and confirm they hold the correct registration.
5. Can you give me a detailed written quote?
A single round figure in a one-line email is not a quote. A proper quote breaks the work down: separate costs for structure, plumbing, electrics, heating and finishes, stated allowances for kitchens, bathrooms and tiling, and a clear list of what is excluded as well as included. It should also show VAT, with the reduced 13.5% rate applied to qualifying construction work. A detailed quote also protects you later, because any changes can be priced against the original brief.
6. What is the payment schedule?
Payment should be tied to completed stages of work, not to calendar dates and not paid largely upfront. A typical deposit for residential building work in Ireland sits between 10% and 25% of the contract sum, with the balance paid in instalments as milestones are reached. A contractor asking for 50% before any materials arrive is asking you to carry all the risk. A contractor who refuses to issue a VAT receipt is a separate warning sign entirely.
7. What is the timeline, and what could delay it?
A competent contractor can give you a realistic start date, a sequence of stages and an expected completion window. Just as important, they will be honest about what could move it, material lead times, weather, or surprises uncovered once work begins. A contractor who promises a perfectly firm date with no caveats is either inexperienced or telling you what you want to hear.
8. Who will be my point of contact on site?
On every project, one person should be accountable. Ask who runs the site day to day, and who you call when you have a question or a problem. If a contractor cannot name that person clearly, accountability will be unclear once the job is underway.
9. Do you provide a written contract?
Every project, however small, should have a written contract. It should set out the scope, the price, the payment schedule, the timeline and how variations are handled. A written contract protects both sides and removes the “but we agreed” arguments later. No contract, no deal.
10. How are changes and variations handled?
Plans shift on almost every project. What matters is how the contractor manages it. A good answer explains how a change is priced, agreed and documented before the work is done, so you are never surprised by a cost. A contractor who is vague about variations is a contractor who may use them to inflate the final bill.
How To Prepare Before You Start Calling Contractors
The questions work best when you have done a little preparation yourself.
Write your scope in plain, specific language. Not “renovate the kitchen” but “remove the existing kitchen, rewire sockets, plumb for a relocated dishwasher, supply and fit new units”. A clear scope gets you comparable quotes.
Set a realistic budget, including a contingency of 10 to 15% for the unexpected, which is especially important in older Dublin homes. Gather any drawings, plans or planning documents you already have. And check what permissions your project needs before work begins, so the contractor is quoting against the real picture.
Hiring With Confidence
The right contractor will welcome every one of these questions. Clear answers, proper paperwork and a written contract are the signs of a contractor who runs projects properly. Vague answers and reluctance to commit anything to writing are the signs to keep looking.
If you are planning building, renovation or civil works in Dublin or the surrounding counties, contact Clarcon for a proper site visit and a detailed written quote. Call 01 437 0645 or email info@clarcon.ie.
