😱 Damp Proofing Makes Damp Worse 🦠 22 Damp Surveys Reveal Real Cause of Mould & Damp #Mould #Damp

00:00 👋 Introduction to April 2026 monthly damp survey summary 01:10 🏚️ Properties 1 and 2 - dry rot, gutter splashback and drain risks 02:35 🦠 Property 3 - mould from subfloor humidity and excess vapour 03:08 🌧️ Property 4 - past penetrating damp plus ventilation issues 03:39 💧 Property 5 - one-off heating leak in a first-floor mansion flat 04:13 🌫️ Property 6 - unheated corridor damp from excess vapour 04:46 🚿 Property 7 - ongoing leak, poor kitchen and bathroom ventilation 05:12 🧱 Property 8 - damp proofing slurry worsening excess vapour risk 05:33 🧂 Property 9 - hygroscopic salts, blocked subfloor ventilation and vacancy 06:29 🦠 Property 10 - Victorian garden flat, mould and subfloor vapour 07:09 🟤 Property 11 - brown staining, excess vapour and past penetrating damp 07:50 🌬️ Property 12 - modern property with mould from poor ventilation 07:59 🏠 Property 13 - Modern house, reverse bathroom ventilation, condensation, vacant at times 08:22 🧱 Property 14 - top wall damp, roof voids and internal vapour 09:11 🏚️ Properties 15-17 - three flats with condensation and poor ventilation 11:08 🚰 Property 18 - blocked gutter, drain leak and subfloor ventilation problems 12:08 🧂 Property 19 - hygroscopic salts, condensation and front wall damp 12:54 🏘️ Properties 19-22 - four flats with damp proofing and subfloor vapour 15:47 📊 Data logger section - comparing dew point and internal vapour 16:40 📈 Data logger - Flat 57 back room versus external conditions 18:00 📈 Data logger - Property 1, very high dew point 18:55 📈 Data logger - Property 2, better than Property 1 19:21 📈 Data logger - Property 3, relatively high vapour levels 19:51 📈 Data logger - Properties 5-7, high internal dew points 20:29 📈 Data logger - Property 8, mostly normal with one high period 20:45 📈 Data logger - Properties 10 and 11, high but variable readings 21:18 📈 Data logger - Properties 13 and 14, vapour, vacancy and loft risk 22:15 📈 Data logger - Property 18, drying walls and winter condensation risk 23:04 📈 Data logger - Properties 19-22, high vapour in the four-flat group 24:16 🌬️ Data logger recap - ventilation replaces internal vapour with outside air 24:54 ✅ Summary - excess vapour, ventilation, dehumidifiers and practical checks SUMMARY This April 2026 monthly summary compares a wide range of damp surveys, showing how similar symptoms can have different root causes. The video moves through the properties in sequence, highlighting dry rot risk, drain defects, guttering and splashback, penetrating damp, hygroscopic salts, mould, condensation, poor ventilation and the damage caused by previous damp proofing. The strongest recurring theme is excess internal vapour, especially where properties are poorly ventilated, left empty, dried internally, or affected by blocked subfloor ventilation. Several cases also show how damp proofing and slurry can worsen the problem by reducing vapour buffering, increasing cold surface risk and moving moisture elsewhere rather than solving the root cause. The data logger section compares internal dew point against external temperature and external vapour conditions. It shows that many properties have internal vapour levels well above outside levels, creating a clear condensation and mould risk, particularly at cold walls, subfloors, roof voids and ground-floor edges. The practical lessons are to test subfloor humidity, check for drain or mains leaks, use data loggers to compare dew point, improve kitchen and bathroom extraction, use a 20-litre dehumidifier where needed, avoid drying clothes internally without extraction or dehumidification, and monitor whether damp is drying from the top down.