Sealing your ceiling is a must for both summer and winter. In winter – to keep a probable 25% of the heat from escaping your home to the roofspace, this will cost extra energy dollars due to air leakage. Air leakage is sourced from penetrations through the ceiling from ventilated skylights, ceiling vents, downlights, ceiling fans, electrical fittings, pipes etc. In summer – if you have air conditioning, air leakage of the ceiling will allow for significant loss of cooled air.
The loss of heated air in winter and the loss of cool air from air conditioning in summer could cost you up to 27% in added energy costs. Not only that the loss of heat to the roofspace due to air leakage can further exacerbate condensation problems in the roofspace not to mention SBS (Sick Building Syndrome) see BLOG on this site “Warning! Read Before You Design Your Next Housing Project”.
SO WHAT ARE YOU TO DO TO STOP AIR LEAKAGE FROM THE CEILING
Start by removing and re-plastering of all ceiling vents or simply tape a heavy paper over the vent. Seal vented skylights, seal around all penetrations, get rid of downlights, duct all ceiling exhaust fans through the roof to the atmosphere, etc.
THEN YOU NEED TO HAVE A CONTINUOUS LAYER OF INSULATION ROOF BATTS COVERING THE ENTIRE CEILING
Make sure there are no gaps and that the insulation extends for the entire ceiling to the extreme outer timber frame. Batts at least R3.5 rating generally fiberglass is cheapest however there are better, more costly forms – polyester wool and real sheep’s wool, sheep’s wool has a higher R rating than the others however comes at a higher cost. Do not get the blown in insulation as this tends to bunch up and leave gaps and definitely do not get spray foam insulation it releases dangerous VOCs into the roofspace – VOCs (volatile organic chemicals). I will not go into that in this BLOG that is the subject for my next blog.
SO YOU HAVE SEALED YOUR CEILING AND CUT DOWN ENERGY COSTS BY AT LEAST 20%
However, although your ceiling is sealed and you are keeping the bulk of your heat in the enclosed space (the home) as heat rises you will still get heat loss through the ceiling and insulation and it is this heat loss that can cause condensation in the roofspace and all the follow on problems – as seen in BLOG “Warning! Read Before You Design Your Next Housing Project”.
YOU NEED TO HAVE AN EFFECTIVE ROOF VENTILATION SYSTEM TO REMOVE CONDENSATION AND ALL THE INHERENT PROBLEMS
Universal Tile Ventilators have very effective roof ventilation systems the Universal Tile Ventilator for tiled roofs and the Smoothline Ventilator for colorbond corrugated roofs.