Thermal Insulation and Spanish CAEs: Walls, Roofs and Deep Renovation

Start with drawings that distinguish façade, roof, floor, party wall and openings. A measure for one opaque element should not absorb surfaces left untouched. When a route refers to renovation affecting more than 25% of the envelope, calculate the relevant denominator and numerator under the sheet definition instead of using 25% of floor area or project cost. Mark every included element on the same drawing used for the area calculation and identify exclusions explicitly.

A deep-renovation code may combine elements but normally demands a coherent building scope. Record which thermal envelope encloses conditioned volume, how adjacent unheated spaces are treated and whether extensions are excluded. A contractor package labelled comprehensive rehabilitation does not itself prove that the regulatory percentage or performance condition has been met. Keep the threshold worksheet aligned with the final construction scope whenever openings, extensions or conditioned zones change.

Openings, cores, balconies and buried portions can change measured façade area materially. Use dimensioned elevations or a traceable digital take-off, state deductions and keep the measurement file. A single gross area copied from cadastral information cannot establish square metres of insulation installed on a particular construction. Survey files should preserve measurement units, drawing scale and revision history so another assessor can repeat the take-off.

The initial U-value requires a defensible layer build-up, not an assumed age-band value whenever the sheet requests project evidence. Surveys, cores, archived drawings and thermal imaging have different evidential strengths. State conductivity, thickness and surface resistances consistently, and identify heterogeneous zones rather than averaging convenient portions. For inaccessible layers, distinguish observed construction from documented assumptions and apply only defaults permitted by the current method.

For the final assembly, link declared thermal conductivity and installed thickness to the exact product. Adhesive, fixings, cavities and protective layers affect constructability, while repeating metal members can affect transmittance. The calculation should represent the completed build-up and the rules in the applicable PDF, not a laboratory panel in isolation. Repeating thermal bridges should be represented consistently where the prescribed transmittance method requires their effect.

If windows, HVAC and insulation are delivered together, define separate energy boundaries and the order of calculations. The same reduction in heating demand cannot be credited once to the envelope and again to a smaller generator. Explain any interaction and preserve the input version used for each measure. Freeze a calculation sequence before combining measures, then recalculate downstream plant effects from the reduced building load.

Photograph representative bays before covering, during placement and after finishing, with location references. Images should show substrate, product labels, thickness checks, continuity at corners and the completed elevation. Delivery notes alone establish material supply, not where or how much was incorporated into the thermal envelope. Location-coded photographs make it possible to reconcile concealed insulation with the measured elevations after scaffolding is removed.

Reconcile bill quantities, measured areas, invoices, waste allowances and the completion certificate. A change from mineral wool to another insulation needs updated conductivity and fire documentation. If site dimensions alter the affected percentage, recalculate the threshold rather than retaining the tender estimate. The completion record should explain substitutions, omitted bays and remedial work instead of merely confirming practical completion.

Thermal bridges at slab edges, parapets, jambs and roof junctions may govern comfort and condensation even when a simplified sheet does not reward every detail. Hygrothermal review, ventilation and rain protection protect the claimed service. Savings caused by lowering indoor temperatures are not envelope efficiency. Check junction temperatures and moisture risk separately from the standardised saving where they govern durability or indoor conditions.

Before relying on a code, review its current sector, dates, exclusions, annexes and threshold wording. Recognition, issuance and commercial value remain separate questions. A sound investment can proceed for comfort or fabric durability, but the financial model should show a scenario in which the CAE estimate is reduced or unavailable. The reference codes for this review are RES010, RES020, RES022, RES080, TER010, TER020 and TER080. Retain a conservative scenario for reduced eligible area or a less favourable initial U-value during commercial review.