Browse Forums General Discussion 1 Jul 09, 2012 10:20 pm Can anyone enlighten me on recommended relative humidity levels for subfloor and roof spaces? Re: humidity level recommendations in homes 2Jul 10, 2012 10:46 am Relative humidity will vary according to atmospheric conditions and is 100% when raining. The most important thing you have to remember is that effective sub floor ventilation is essential to stop increase of humidity due to ground moisture and trapped air. Roof space ventilation is also essential because many shower vents discharge into roof space Foremost Building Expert in Australia,assisting with building problems/disputes, building stage inspections,pre-contract review advice for peace of mind 200 blogs http://www.buildingexpert.net.au/blog Re: humidity level recommendations in homes 3Jul 10, 2012 12:33 pm building-expert Relative humidity will vary according to atmospheric conditions and is 100% when raining. Humidity is 100% when no evaporation is occurring - that not the same as rain. Even when its pouring down with rain evaporation still occurs. Relative humidity in the 80 -90 percent range is quite common during rain. The main issues are 1.To vent moist air out of the building 2. Have effective vapour barriers to avoid humidity condensing in the walls/insulation 3. Ventilate subfloor and roofspace The Harder You Try - the Luckier You Get ! Web site http://www.anewhouse.com.au Informative, Amusing, and Opinionated Blog - Over 600 posts on all aspects of building a new house. Re: humidity level recommendations in homes 4Jul 11, 2012 6:17 pm thanks for your responses but what i was after were any recommendations about the upper limits of relative humidity for subfloor and roof space respectively. i know that for inside the house it is recommended that humidity be maintained below 60% and preferably in the range 30-50%. are there any similar recommendations for the subfloor and roof space? mark Re: humidity level recommendations in homes 5Jul 11, 2012 6:40 pm If your subfloor is well ventilated you wont have problems with it. In blocked air spaces humidity will increase (from ground moisture etc) Permanent high levels of humidity will be absorbed into timber. Once timber moisture content is around 18% or more it becomes attractive to termites, rot, borers and mould. Normal timber moisture content is 8-12% You don't need to control humidity other than natural ventilation Foremost Building Expert in Australia,assisting with building problems/disputes, building stage inspections,pre-contract review advice for peace of mind 200 blogs http://www.buildingexpert.net.au/blog isn't a garage level with the rest of the house a given? pretty sure they 'came around' long time ago. if you have a flat block, the garage is usually level with the rest… 1 17525 they can, it's a fairly standard solution when the slab isn't recessed. the falls need to be in the main floor, if it hasn't been done then you need to ask them to redo… 4 6584 interesting situation what happened after builder issued final invoice? did you list as defect or not does the building surveyor have any responsibility? ie. issuing… 13 46960 |