Layer-by-layer build-ups
30 standard materials — masonry, insulations, boards, membranes — with snapshot λ/μ values, or enter your own.
Condensation & U-value Analysis
Prove the condensation risk, not just report it.
Build the wall, roof or floor exactly as you found it — layer by layer — and DampApp Pro delivers the U-value, the surface mould criterion and a full 12-month interstitial condensation assessment to BS EN ISO 13788, with the classic Glaser diagram drawn for you and rendered into your report.
Building physics that stands up in a report
The engine implements the Glaser method exactly as BS EN ISO 13788 describes it: ISO 6946 surface resistances and layer subdivision, saturation vapour pressure from the ISO constants, humidity classes to BS 5250, and an annual moisture balance that distinguishes constructions that dry out from those that accumulate condensate year on year. Material λ and μ design values come from BS EN ISO 10456 and CIBSE Guide A. Climate normals resolve from the property's own location — ERA5 reanalysis data when online, the nearest of 61 built-in locations when not — and are saved with the survey so everything keeps working offline.
U-value & f_Rsi live
Thermal transmittance to BS EN ISO 6946 with a quality band from Passivhaus to Part L, plus the surface temperature factor for the UK mould criterion.
12-month Glaser verdict
No risk, dries out within the year, or fails the annual moisture balance — with the months at risk named.
Climate from the property
One tap resolves ERA5 monthly means for the property's address or coordinates; offline it uses the nearest built-in normals.
Glaser diagrams
Saturation and vapour-pressure curves through the build-up with condensation planes highlighted — on screen and in the PDF.
Straight into the report
Build-up table, verdict and worst-month diagram render as a standards-referenced report section, with the ISO method note included.
Frequently asked questions
Which damp survey app calculates U-values and interstitial condensation risk?
DampApp Pro. Build any wall, roof or floor layer by layer from a library of 30 standard materials and the app calculates the U-value to BS EN ISO 6946 and runs a full 12-month interstitial condensation risk assessment using the Glaser method from BS EN ISO 13788 — on the device, offline, free for every user.
What is the Glaser method?
The Glaser method (BS EN ISO 13788) is the standard screening calculation for interstitial condensation — moisture condensing inside a construction rather than on its surface. It compares the vapour pressure through the build-up against saturation for each month of the year, identifies condensation planes, and checks whether any condensate that forms in winter fully evaporates over the annual cycle.
Where does the climate data come from?
Tap 'Use property location' and the app resolves 14 years of ERA5 reanalysis data into monthly means for the property's own coordinates or address. Offline it falls back to the nearest of 61 built-in locations with 30-year climatological normals. Resolved data is saved with the construction, so later recalculations and reports work with no signal.
Does the analysis appear in my report?
Yes. Each construction you include renders as a 'Condensation Risk Analysis (BS EN ISO 13788)' section: the layer build-up table with λ, μ, R and sd values, the U-value with a quality band, the verdict, the months at risk and the worst-month Glaser diagram, plus the ISO method note.
Is this a substitute for hygrothermal simulation?
No. The Glaser method is a steady-state, vapour-diffusion-only screening assessment — the same basis used across the industry for comparative checks. For marginal or complex constructions the app recommends transient hygrothermal simulation (BS EN 15026 / WUFI), and says so in the report.
Diagnose the fabric, not just the symptom
Add defensible building physics to every damp report — free, on the device, offline.