Why Spanish construction often uses only 2–4 cm of insulation – and what the real consequences are

A complete guide to insulation, comfort, and why prefabricated timber frame construction in Spain performs so much better.

1. The reality: traditional Spanish construction has almost no insulation

It sounds unbelievable, but it's true:

Most traditional builders in Spain only use 2 to 4 cm of insulation in the external walls.

In many homes you will find:

• 2 cm white EPS plates
  
  

• 3 cm XPS
  
  

• 4 cm PUR as a luxury exception
  
  

• Or even no insulation in older houses
  
  

Concrete blocks, bricks, and hollow ceramic blocks have virtually no insulation value. This makes a house physically warm in summer and freezing cold in winter.

This is one of the biggest problems with the Spanish housing stock.

2. Why do Spanish builders use so little insulation?

a) The focus is on construction price, not on quality

Many projects are built for the lowest price.

Insulation = extra costs → so the minimum is used.

b) Misconception: “Spain is warm, so insulation is not necessary.”

This is incorrect. In warm climates, insulation provides protection against heat.

c) Building code (CTE DB-HE) is not strictly monitored

The standard is already low, but many builders don't even meet that standard.

d) Lack of training in modern building physics

Most of the contractors work with traditional techniques which are not modern.

3. The consequences of insufficient insulation

1. Overheating in summer

Thin walls let the heat through as if it were nothing →

The air conditioning is on all day.

2. Cold walls and damp problems in winter

Outside 8–12°C, inside warm, breathable air with moisture → condensation on walls → mould formation.

3. Large temperature differences day & night

On the coast (Alicante, Murcia, Málaga) temperatures often drop 12–18°C in one night.

This causes moisture, mold, and an uncomfortable indoor climate.

4. High energy bills

A poorly insulated house loses up to 70% of the cooled/heated air through the walls.

4. What does the Spanish building code require – and what really happens?

Here's the comparison:

Conclusion:

Spain is building as if it were 15 years ago.

The insulation values are two to three times lower than modern European standards.

5. That's why prefabricated timber frame construction is the future of Spain

Prefabricated timber frame construction (such as UrbanRise Eco Homes) uses insulation as the main system, not as a by-product.

Typical UrbanRise wall construction

• 6.0–6.5 cm installation zone
  
  

• 12.5 mm OSB
  
  

• Vapor-tight or vapor-controlled foil
  
  

• 16 cm insulation in the main frame (Insulation class A)
  
  

• 12.5 mm OSB outside
  
  

• 6–8 cm wood fiber insulation (Steico Protect type)
  
  

• Plasterwork or facade finishing
  
  

Total insulation package = 22–30 cm

→ 6 to 10 times more than traditional Spanish construction.

Advantages:

• No cold bridges
  
  

• No condensation
  
  

• No mold
  
  

• Cool in the summer
  
  

• Warm in winter
  
  

• Up to 70% lower energy costs
  
  

• Proven system (Scandinavia, Canada, Germany, Netherlands)
  
  

6. The oldest buildings in the world prove it

Many of the oldest inhabited buildings in:

• Japan
  
  

• Scandinavia
  
  

• Canada
  
  

• Alpine region
  
  

are based on timber building traditions.

Wood is strong, durable, insulating and adapts to the climate.

The principle behind modern prefabricated construction is old and extremely reliable.

7. Summary – why Spanish construction uses 2–4 cm insulation, and why that is no longer possible

❌ Traditional construction in Spain:

• 2–4 cm insulation
  
  

• High energy bill
  
  

• Moisture problems
  
  

• Large temperature differences
  
  

• Low build quality
  
  

Modern prefabricated timber frame construction:

• 22–30 cm insulation
  
  

• Cool in the summer
  
  

• Warm in winter
  
  

• Healthy indoor climate
  
  

• No condensation or mold
  
  

• Very low energy costs