Condensation Risk Analysis UK | Damp Prevention

Q: What is condensation risk analysis and when is it needed?

Condensation risk analysis evaluates whether a proposed or existing building construction is at risk of surface condensation on visible surfaces or interstitial condensation within the building fabric. It is needed whenever insulation is being added to walls, roofs, or floors, particularly with materials that change the dew point within the construction. PAS 2035 requires consideration of moisture risk in all retrofit designs.

Q: What is the difference between surface and interstitial condensation?

Surface condensation forms on the inside face of walls, windows, or ceilings when their surface temperature drops below the dew point of the room air, typically causing mould growth. Interstitial condensation forms within the building fabric itself when warm, moist air migrates through the construction and reaches a cold layer where it condenses. Both types are assessed by StepSoft using BS EN ISO 13788 methodology.

Q: How does StepSoft carry out condensation risk analysis?

StepSoft uses the Glaser method in accordance with BS EN ISO 13788 to assess interstitial condensation risk. This involves calculating moisture transfer through each layer of the construction across winter and summer conditions, identifying whether condensation forms and whether it dries adequately during warmer months. For complex constructions, dynamic hygrothermal simulation may also be recommended. Reports are produced in a format suitable for PAS 2035 compliance evidence.

Q: Can condensation risk analysis prevent mould problems after retrofit?

Yes. By identifying condensation risks before installation, StepSoft analysis allows the design to be adjusted, for example by adding a vapour control layer, specifying a more vapour-permeable insulation, or recommending improved ventilation. Addressing these issues at the design stage is far less costly than remedying damp and mould after installation.

Q: Is condensation risk analysis required for ECO4 scheme compliance?

Yes. PAS 2035, which underpins ECO4 and GBIS compliance, requires Retrofit Designers to consider moisture risk in all retrofit designs. For medium and high-risk projects, formal condensation risk analysis is expected as part of the design evidence. Scheme auditors and managing agents may request this documentation, and StepSoft ensures it is produced and retained within the project file.

Condensation Risk Analysis Services

At StepSoft Coordination Services, we provide professional condensation risk analysis to identify and prevent moisture-related issues in buildings. Our expert assessments help ensure that retrofit and insulation measures do not create condensation problems while maintaining compliance with PAS 2035 standards and building regulations.

What is Condensation Risk Analysis?

Condensation Risk Analysis evaluates the likelihood of moisture forming within building structures due to temperature differences and inadequate ventilation. If not properly addressed, condensation can lead to dampness, mold growth, and structural damage.

Prevent Damp and Mold

Helps identify moisture risks that can lead to mold growth and building damage.

Protect Building Structure

Ensures that insulation and retrofit measures do not trap moisture inside walls or roofs.

Improve Indoor Air Quality

Reduces the risk of unhealthy indoor environments caused by damp conditions.

PAS 2035 Compliance

Supports safe retrofit planning that complies with industry standards and regulations.

Our Condensation Risk Analysis Process

Building Structure Review

Moisture & Temperature Analysis

Thermal Performance Modelling

Risk Identification

Reporting & Recommendations

Why Choose StepSoft Coordination Services

Benefits of Professional Retrofit Coordination

Healthier Living Environment

Prevent mold and damp conditions that affect indoor air quality.

Long-Term Building Protection

Protect building materials and structure from moisture damage.

Safer Retrofit Implementation

Ensure energy efficiency improvements do not create unintended moisture problems.

Let's Discuss Your Retrofit Needs

Accreditations & Certifications

FAQ 's

What is condensation risk analysis and when is it needed?

Condensation risk analysis evaluates whether a proposed or existing building construction is at risk of surface condensation (on visible surfaces) or interstitial condensation (within the building fabric). It is needed whenever insulation is being added to walls, roofs, or floors — particularly with materials that change the dew point within the construction. PAS 2035 requires consideration of moisture risk in all retrofit designs.

What is the difference between surface and interstitial condensation?

Surface condensation forms on the inside face of walls, windows, or ceilings when their surface temperature drops below the dew point of the room air — typically causing mould growth. Interstitial condensation forms within the building fabric itself when warm, moist air migrates through the construction and reaches a cold layer where it condenses. Both types are assessed by StepSoft using BS EN ISO 13788 methodology

Which insulation types carry the highest condensation risk?

Insulation types that change the vapour pressure profile through the wall carry the greatest risk. Internal wall insulation (IWI) is the highest-risk scenario, as it cools the original wall behind the insulation. Solid wall constructions, older buildings with mixed materials, and any retrofit where a vapour barrier is absent or incorrectly positioned are also higher risk. StepSoft analyses each construction type individually.

How does StepSoft carry out condensation risk analysis?

StepSoft uses the Glaser method (BS EN ISO 13788) to assess interstitial condensation risk. This involves calculating moisture transfer through each layer of the construction across winter and summer conditions, identifying whether condensation forms and whether it dries adequately during warmer months. For complex constructions, dynamic hygrothermal simulation may also be recommended. Reports are produced in a format suitable for PAS 2035 compliance evidence.

Can condensation risk analysis prevent mould problems after retrofit?

Yes — this is precisely the purpose of the assessment. By identifying condensation risks before installation, StepSoft’s analysis allows the design to be adjusted: for example, by adding a vapour control layer, specifying a more vapour-permeable insulation, or recommending improved ventilation. Addressing these issues at the design stage is far less costly than remedying damp and mould after installation.

Is condensation risk analysis required for ECO4 scheme compliance?

Yes. PAS 2035 — which underpins ECO4 and GBIS compliance — requires Retrofit Designers to consider moisture risk in all retrofit designs. For medium and high-risk projects, formal condensation risk analysis is expected as part of the design evidence. Scheme auditors and managing agents may request this documentation, and StepSoft ensures it is produced and retained within the project file.

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