Water dripping back along bathroom extractor hose from roof vent in freezing weather (not rain!).

Hi usually it is because the extractor hose has a bend in it or the unit is not strong enough to cope ,they need to be straight up through the roof ideally from the source rather than running through the loft.

It sounds like the issue might be related to condensation or moisture buildup in the bathroom extractor hose, especially during freezing weather. Here are a few potential causes and solutions: 1. **Condensation Buildup:** If warm, moist air from the bathroom is getting into the extractor hose but isn't being properly vented outside, it can lead to condensation inside the hose. In freezing temperatures, this condensation can freeze and cause water to drip back down. - Check the insulation around the hose and ensure it's properly installed without any pinching that could restrict airflow. - Ensure the hose is properly connected to the roof vent and there are no gaps or leaks where moisture could escape. 2. **Roof Vent Design:** Roof vents typically have a flap or a design that prevents water from entering but allows air to escape. If the vent is damaged, clogged, or improperly installed, it might allow moisture to accumulate and freeze, causing dripping. - Check the roof vent for any damage, blockages, or improper installation that could allow moisture to accumulate. - Clean the vent to ensure there's no debris blocking proper airflow. 3. **Insulation and Ventilation:** Proper insulation in the attic and good ventilation in the bathroom are essential to prevent condensation buildup in the extractor hose. - Inspect the attic insulation to ensure it's not blocking airflow and causing moisture to condense in the hose. - Consider improving bathroom ventilation or using a dehumidifier to reduce moisture levels in the air. If you suspect the issue is primarily due to freezing of condensation in the hose, ensuring proper insulation, ventilation, and checking the roof vent for any issues should help mitigate the problem. If you're unsure or if the issue persists, consulting a professional roofer or HVAC specialist might provide a more detailed assessment of the problem and the best course of action.