The roof cavity can make a home very inefficient when it comes to heating and cooling your home. In fact 40% of the heating and cooling energy loss is through the roof cavity. Insulation plays an important role in keeping your home warmer in winter and cooler in summer. However in summer the heat can be trapped in the roof cavity long after the sun has gone down. Adding a roof vent improves the efficiency of your insulation in summer and removes moist air in winter.

Types of roof vents

Wind-driven: This type of roof vent removes the air from the roof cavity via the wind turning the turbine and sucking the air from the roof cavity. These wind vents are easy to install with a few basic tools and can be found at most hardware stores. They can be installed on both tile and metal roofs and should last for many years. One per 90 metres square of ceiling area is suggested.

Pros: Effective, inexpensive, no cost to run, silent.

Cons: not as effective on hot still days, does not move as much air as powered units.

Powered vents: These can be mains or solar powered. The mains powered vents can be set to come on at a set temperature. Solar powered units start with the sun and are very effective in removal of air. These powered units move much more air than the wind powered vents and do not sit as high on the roof. However they are installed in the same way as the wind powered vents with an electrician needed for the mains powered vent.

Pros: Very effective, solar vent runs at no cost, silent.

Cons: More expensive than wind powered vents, mains powered unit costs to run and costs more to install.

How to install a roof vent

Step one: Position: Select the best position for the vents close the ridge or top of the roof. For metal roofs place the vent flashing under the ridge capping and mark the position on the roof.
For tiled roofs remove a tile in the third row from the ridge cut any sarking corner to corner and fold back.

Step two: Make the hole: For both roof types make sure your hole is the between the roof joists. For metal roofs be sure the flashing covers the corrugations equally. Cut the hole in the metal to suit the vent. For tiles bend the top of the flashing up to stop water and push the top flashing under the tile above the hole. Use a rubber mallet to mould the flashing to the side and bottom tiles.

Step three: Waterproof the flashing: This is an important step of get right and with attention to detail being the key. For metal roofs run a bead of silicone along the underside of flashing and then secure it to the roof with self-tapping screws. Also make sure the cylinder has been secured to the roof frame or battens. For tiles roofs secure the cylinder to the roof frame and run a bead of silicone around the side and bottom of the flashing so the wind cannot blow it up and blow rain under it.

Step four: Install the vent top: Secure the top of the fan section. Adjust the ventilator cylinder to the pitch of the roof (only for wind powered vents). Secure the top with three metal screws and seal over with silicon. Then check the working order of the vent and check that no water will be able to enter. Seal any areas that may leak with silicon. Job done! Re-check the vent for any leaks after rain.

By Steven Robinson – Renovation Robot
Want to know more and see repairs in action then visit the Renovation Robot web site for free advise and tips!
Click here —->http://www.renovationrobot.com.au.