Fitting a brand-new kitchen is exciting, but it can quickly turn stressful if something gets damaged during installation. One of the most common problems we see is damage to sinks when cutting or knocking out tap holes. In most cases, this happens because the correct instructions haven’t been followed, or shortcuts were taken to save time – often resulting in a cracked or ruined sink.
At Taps UK, we’ve put together a detailed guide on how to correctly knock a tap hole in ceramic and granite sinks. Alongside this, our in-house fitter, who provides a professional tap hole preparation service for customers, has shared his best practices and expert tips for avoiding mistakes.
Below, we’ve highlighted some real examples of what can go wrong when the process isn’t done correctly, along with explanations of why these issues happen – so you can avoid the same costly errors.
One of the most common mistakes during tap hole installation is trying to knock the hole through from the underside of the sink. Doing this creates stress fractures and a “mushroom effect” that chips away at the sink’s finish.
Always knock the tap hole from the top surface of the sink.
Damage like this is rarely a manufacturing fault.
Manufacturers often dismiss these cases as installation errors, meaning you’ll usually need to claim through your fitter’s insurance.
Another frequent problem happens when the installer doesn’t hit the centre of the tap hole. Punching away from the marked centre can crack the wrong section of the sink.
Carefully mark the centre point before starting.
Double-check your positioning before applying force.
Good preparation avoids costly mistakes.
As the saying goes, “ fail to prepare, prepare to fail.” With ceramic and granite sinks, preparation is crucial. Drilling from the underside first helps reduce resistance and makes knocking out the hole much safer.
Drill the underside to reduce the material thickness from 10–15mm down to 2–3mm.
Less resistance = less force needed = less risk of breakage.
Too much force applied to thick material is the main cause of cracks.
It might sound obvious, but your sink must be fully supported before punching a tap hole. An unsupported sink is far more likely to crack or, in worst cases, completely shatter.
Mistakes can happen, even with experienced installers. In these cases:
Competent fitters should have professional insurance to cover accidental damage.
If the fault isn’t covered under warranty, raise a claim through your fitter.
Our customer service team is also here to help with advice and possible solutions.
📞 Call us on 01527 868 510 or email helpdesk@tapsuk.net if you need assistance.
Knocking through a tap hole may seem simple, but the smallest mistake can ruin a brand-new sink. By taking the time to prepare properly, working from the top surface, and ensuring the sink is fully supported, you can avoid the common installation errors that lead to costly damage. If you’re unsure, using a professional service or opting for our tap hole pre-drilling option gives you peace of mind and a sink ready to fit straight away.
