1. Small cracks in wall corners

What they indicate:

• plaster shrinkage,

• old settlement movement,

• low-quality finishing,

• rarely, deeper structural tension.

How to spot it in seconds:
Check the corners and around windows/doors.
Hairline cracks are normal.
Wider, darkened or expanding cracks → warning.

2. Bubbling or swelling at the base of walls — rising damp

What it means:

• moisture coming from the floor slab,

• poor waterproofing,

• leaks from communal areas.

What to look for:
Lines, bubbles, peeling paint, or swollen plaster near the floor.

3. A hollow sound when tapping the wall

What it reveals:

• poor masonry,

• lack of density,

• minimal acoustic insulation.

How to test:
Tap the wall gently in 4–5 spots.
If the sound is hollow, the wall lacks mass → internal noise will travel easily.

4. Gaps or air leaks around windows

What they mean:

• poor installation,

• thermal loss,

• future moisture issues,

• higher heating/cooling costs.

Quick test:
Run your hand around the window frame.
If you feel air → the installation is flawed.

5. Mold spots on ceilings and bathrooms

Caused by:

• insufficient ventilation,

• thermal bridging,

• water penetration from above,

• moisture trapped in old construction.

Where to check:

• corners of ceilings,

• above the shower,

• near ventilation ducts.

Even a tiny black dot can reveal a deeper humidity issue.

6. Tiles that “click” or move slightly under pressure

What it indicates:

• poor adhesion,

• water underneath,

• potential for future detachment.

Test:
Walk slowly across bathroom/kitchen tiles.
If you hear “tick-tick”, the substrate isn’t solid.

7. Damp or “closed” smell upon entering

What it reveals:

• hidden moisture,

• old leaks,

• insufficient airflow,

• degraded insulation.

A home should smell neutral.
Moisture smell = guaranteed issue.

8. Noise from upstairs or adjacent walls

What it means:

• thin partitions,

• no acoustic insulation,

• poor slab design.

How to test in 30 seconds:
Ask for a moment of silence.
If you hear conversations, footsteps, plumbing or TV noise → low acoustic comfort.

9. Temperature differences between rooms

What this indicates:

• heat loss,

• weak insulation,

• thermal bridges,

• low-performance windows.

Test:
Move from living room to bedrooms.
A noticeable temperature shift means energy inefficiency.

10. Weak water pressure — the invisible red flag

What it means:

• clogged pipes,

• old plumbing network,

• poor pressure pump setup,

• installation defects.

Quick test:
Turn on the kitchen faucet and bathroom faucet simultaneously.
If pressure drops → there's a plumbing issue.

How Professionals Check an Apartment in 5 Minutes

1) The Sound Test

Tap walls, floors, doors — sound reveals density and construction quality.

2) The Light Test

Open shutters or curtains — observe natural light, shadows, and opposite building distance.

3) The Air & Moisture Test

A simple smell test can reveal hidden humidity within two seconds.

These reveal 80% of the property’s condition instantly.

Why These Defects Matter for Real Value

Hidden defects directly affect:

• resale value,

• rental performance,

• maintenance cost,

• structural longevity,

• tenant satisfaction.

A property with moisture, noise, weak pressure or hollow walls:

• deteriorates faster,

• rents slower,

• costs more over time,

• loses long-term value.

Real Example: The Tymfristou Project by Poli Real Estate

Poli Real Estate evaluates every property using this exact professional checklist.

At the Tymfristou development in Marousi:

• wall density is reinforced,

• premium windows eliminate air leaks,

• acoustic tests are conducted per room,

• plumbing pressure is benchmarked,

• humidity control and insulation are double-checked,

• temperature stability is ensured,

• anti-vibration materials are used in floors,

• a full quality inspection occurs before delivery.

This is why boutique developments like Tymfristou hold their value and maintain exceptionally high demand.

Conclusion

Most hidden defects are easy to detect — if you know what to look for.

Remember:

✔ square meters don’t reveal true quality
✔ hidden flaws are the most expensive
✔ 5 minutes of inspection can save thousands
✔ noise, moisture, and installation quality define long-term comfort

If you want a professional evaluation of a property — or guidance on high-quality new developments — Poli Real Estate can assist you with expert-level assessments and transparent reporting.