Signs your extension wasn’t built properly

A home extension should add value, space, and comfort to your property. When it is built properly, it should feel like a natural part of your home. Unfortunately, poorly built extensions are more common than they should be.

As builders working across the West Midlands, we are often asked to inspect extensions where problems have started to appear months or even years later. Below are some clear signs that an extension may not have been built to a good standard.

Cracks in walls or ceilings

Small hairline cracks can be normal as a building settles. Large cracks, widening cracks, or cracks that keep reappearing can indicate structural issues or poor foundations.

Doors and windows sticking

If doors or windows are hard to open or close, it could mean the extension has moved or was not built level. This is often a sign of foundation problems or poor structural support.

Damp patches or mould

Damp is one of the most common issues in poorly built extensions. Signs include mould, peeling paint, or dark patches on walls and ceilings. This can be caused by poor insulation, missing damp proofing, or bad drainage.

Uneven floors

Floors should feel solid and level. If the floor slopes, feels bouncy, or has noticeable dips, it may be due to poor groundwork or incorrect floor construction.

Poor roof workmanship

Look for signs such as sagging rooflines, loose tiles, or leaks after rainfall. A poorly built roof can lead to ongoing water damage and costly repairs.

Cold rooms and high energy bills

If your extension feels much colder than the rest of your home, it may not be insulated correctly. Poor insulation leads to heat loss and higher heating costs.

Poor drainage or standing water

Water pooling near the extension or slow draining gullies can indicate incorrect ground levels or poor drainage installation. Over time, this can cause damp and foundation issues.

Mismatched materials or finishes

While some variation is normal, a well built extension should blend with the existing property. Poor matching bricks, uneven brickwork, or untidy finishes can suggest rushed or low quality work.

Lack of building control approval

If you do not have building control sign off or completion certificates, this is a serious concern. Work that has not been properly inspected may not meet safety or structural standards.

Problems appearing quickly

A quality extension should last for decades. If issues start appearing within the first year or two, it often points to shortcuts being taken during the build.

What to do if you are concerned

If you notice any of these signs, it is important to act early. Small issues can quickly turn into expensive repairs if left unresolved. A professional inspection can help identify the cause and the best way to fix it.

If you are based in the West Midlands and are worried about the quality of an existing extension, or are planning a new one and want it done right first time, give us a call today. We would be happy to offer honest advice and provide a clear, no obligation quote.