Insulation outside
Gypsum plaster 15 · perforated brick 240 · EPS 100 · mortar render 10 mm
U-value
0.304
W/(m²·K)
Moisture
No condensation in any month of the year.
Glaser diagram · January
Descarboniza · Tool
Condensation and U-value,
month by month.
Draw the build-up from inside to outside and see, all at once, how well it insulates, in which month it condenses and how it behaves in summer. Using the method of the Spanish guidance document DA DB-HE/2 and the climate of your municipality.
Free with your account · beta · editor in Spanish
Same brick wall, insulation outside or inside.
A one-brick-thick wall in Burgos, for a dwelling. Two solutions: what changes is where the dew point falls and, with it, what happens inside the wall.
Insulation inside
Plasterboard 15 · mineral wool 60 · perforated brick 240 · mortar render 10 mm
U-value
0.467
W/(m²·K)
Moisture
Condenses from November to April, against the insulation: up to 4.7 kg/m² builds up and evaporates before the year is out.
Glaser diagram · January
The insulants are not the same (EPS outside, mineral wool inside), so we do not compare the U-values: we compare where the vapour pressure sits relative to saturation. Material data from the Catalogue of Construction Elements of the Spanish building code (CTE) and Burgos climate from table C.1 of DA DB-HE/2. In the editor you can change any of them.
Five checks, one screen.
UEN ISO 6946
Layer by layer, studs included
Unventilated, slightly ventilated and well-ventilated air layers. Studs and battens with the standard's combined method, with its maximum error shown.
12months · DA DB-HE/2
Glaser in every month
Not one typical January: the monthly climate of the 52 Spanish provincial capitals, corrected for the altitude of your municipality. Plus the ISO 13788 annual balance: how much condenses, how much evaporates and whether any water is left.
fRsisurface
Mould, checked separately
Temperature factor of the internal surface against the minimum in table 1 of the DA and against the one calculated for your location.
hEN ISO 13786
And summer
Time lag, decrement factor and internal heat capacity. What DB-HE1 does not quantify, and what changes most between a heavy wall and a light one.
CO₂A1–A3 · kg/m²
Carbon, layer by layer
Each layer with its figure from the Descarboniza catalogue and its data quality: A for the product's own EPD, B for a sector-wide one, C for generic data. A layer with no data is never filled with an assumed figure: it is flagged.
How it worksNo black box.
No black box.
Every figure, with its source.
The materials come from the Catalogue of Construction Elements of the Spanish building code: 338 of them, with conductivity, density, specific heat and vapour resistance. If your manufacturer declares other values, you change them in the layer and it is flagged as your own data. And every tab says which standard and which clause applies.
- UNE-EN ISO 6946 · thermal resistance and transmittance
- DA DB-HE/2 (Oct 2013) · surface and interstitial condensation
- UNE-EN ISO 13788 · annual condensation balance
- UNE-EN ISO 13786 · dynamic thermal characteristics
What it does NOT do.
The limitations, before they surprise you on site. And why.
It is Glaser, not a simulation
Steady state with monthly means: it does not account for the moisture each material stores, for capillarity or for rain. It usually errs on the safe side. But timber or driving rain call for a transient simulation (EN 15026), and we do not offer that yet.
Thermal bridges, separately
It gives the U-value of the plain wall area. Studs are included through the ISO 6946 method; a slab edge or a lintel needs a 2D calculation.
It is not a certificate
It is an indicative design calculation. The justification is signed by the responsible professional, and each material's data must be checked against the manufacturer's.
Frequently asked questions.
It is the condensation that forms inside the build-up when the vapour pressure reaches saturation in some layer. The Spanish guidance document DA DB-HE/2 says it does not need checking in elements in contact with the ground, or in those with a vapour barrier on the warm side.
It is the one on the inner face, the one that causes mould. It is checked with the temperature factor of the internal surface (fRsi = 1 − 0.25·U) against the minimum in table 1 of the DA, which depends on the indoor humidity class and the winter climate zone. The DA states that meeting the maximum U-values of DB-HE1 ensures that condition in spaces of humidity class 4 or lower, although thermal bridges may still need checking.
The DA asks for January for the strict check. But when condensation forms outside the insulation, it recommends that what condenses in a year should not exceed what can evaporate, and that only shows when you run through all twelve months. That is what ISO 13788 does, and what we draw in the annual balance.
From table C.1 of DA DB-HE/2: mean monthly temperature and relative humidity for each Spanish provincial capital. For any other municipality, the DA allows taking the capital with 1 °C less for every 100 m of altitude difference and the same absolute humidity. That is what we apply.
Not as it stands. The physics is the international one (ISO 6946, ISO 13788, ISO 13786), but the climate comes from the Spanish code and you can only choose locations in Spain. The limit values and the report follow the Spanish building code (CTE) too.
The DA describes “some procedures that may be used” and accepts others with sufficient technical soundness; here we apply its own and keep every figure and its source in view. Even so, it is an indicative calculation: before taking it into the project report, check your materials' properties against the manufacturer's. Catalogue values are averages.
Drawing, calculating and seeing the result is free with your account, and you can copy a link that reproduces your exact build-up. Taking away the justification as a PDF, with the DA DB-HE/2 method set out and a signature block, comes with the studio or contractor plan, like the rest of our documents. It is in beta, and both the editor and the PDF are in Spanish.
Draw your wall.
See what happens to it in January.
Descarboniza · Build-up editor
Free with an account · Beta