Frequently asked questions.

A building performance diagnostic is a measured investigation of how your building actually performs — heat loss, air leakage, moisture, condensation risk, ventilation and comfort. Rather than guessing, we use calibrated instruments (thermal imaging, blower door, moisture meters, data loggers) to find the root cause of a problem and then design a remediation that addresses it. It is measurement-based building diagnostics, not guesswork.

A blower door is a calibrated fan fitted into an external doorway that pressurises or depressurises your home to a set pressure (usually 50 Pa). It measures exactly how much air leaks through the building envelope (ACH₅₀ and m³/h). Combined with smoke tracing and thermal imaging under depressurisation, it pinpoints every individual leak path so air-sealing work can be targeted and verified.

Yes — indirectly. A calibrated FLIR thermal camera measures surface temperature. Evaporating moisture cools a surface, so hidden damp often appears as a cooler area. Thermal imaging also reveals surfaces below the room's dewpoint, which is direct evidence of condensation risk. We always confirm findings with moisture meters and humidity logging, because a cold patch can have several causes.

Yes. Heat loss through missing or compressed insulation, thermal bridges (lintels, reveals, floor junctions) and air leakage shows up clearly as cold or warm patterns when there is a sufficient temperature difference between inside and outside. This is one of the most valuable uses of a thermal survey before planning any insulation or retrofit work.

Yes. Thermal imaging readily reveals gaps, slumping, compression and missing sections in insulation — both in existing properties and as a post-installation quality check. We can verify cavity, loft, internal wall and underfloor insulation, and combine this with a blower door test where airtightness is also a concern.

Condensation forms when warm, moist indoor air meets a cold surface that is below its dewpoint — it is driven by indoor humidity and cold surfaces. Penetrating damp is water entering from outside through defects such as failed pointing, cracked render or blocked gutters. They look similar but need completely different fixes, which is why we diagnose with measured data before recommending any works.

Yes. Every diagnostic survey is followed by a clear written report with annotated photographs, calibrated thermal images, measured data (temperatures, humidity, air-leakage figures where applicable), a diagnosis of the root cause and a prioritised, costed remediation plan. The report is yours to keep and to share with architects, surveyors or contractors.

Yes. We are based in East London (E15) and cover Greater London, Essex, Kent, Surrey, Hertfordshire and the wider South East. If you are unsure whether we cover your area, just get in touch.

Yes. Unlike a survey-only provider, we follow a single process — Investigate → Diagnose → Design → Remediate → Verify. We can carry out the recommended works (insulation, airtightness, soundproofing, ventilation, damp remediation) ourselves and then verify the outcome with measurement. One company, one process, one point of responsibility.

Cost depends on the property and the scope — a single-room damp investigation is very different from a whole-house diagnostic with a blower door test. We give you a clear, fixed price before any work begins, with no obligation. Contact us with a short description of the issue (photos help) and we will recommend the most cost-effective survey and quote it.

For a thermal survey, keep your heating on for at least 24 hours beforehand so internal surfaces are stable, and clear access to the walls and areas of concern. For a blower door test, keep external doors and windows closed during the test. Send us any photos and a description of the symptoms in advance so we can plan the most useful survey. We'll confirm exactly what's needed when we book you in.

Insulation and air-sealing make a building tighter, which is good for energy and comfort but reduces accidental ventilation. Without a controlled ventilation strategy (such as MVHR, dMEV or PIV), indoor humidity, CO₂ and pollutants can build up and cause condensation and mould. That's why we always assess ventilation alongside any fabric upgrade — fixing one without the other can move the problem rather than solve it.