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Sloped roof, with dormers, slopes or cathedrals
This will allow exterior air to enter into the attic and to circulate evenly; the peak ventilator then draws and exhausts all excess heat and humidity. This type of building requires installing a Maximum Ventilator for every 600 square feet of insulated ceiling.
If this is neglected, these openings located at the rafter level will inhibit ideal air circulation, which starts at the bottom and rises. The air that comes in through these openings will be drawn up by the ventilator, limiting air circulation to the rafter area only.
The solution is to increase ventilation, making sure that there are no openings other than the soffits and the Maximum ventilators installed at the gable using a rooftop flashing, or on the rear slope of the roof.
In this case, Ventilation Maximum recommends the installation of a special product: our 50% Soffit enabling adequate ventilation to this problem area. It is also preferable to install the ventilators on the side of the roof opposite the dormers. This type of building requires installing a Maximum Ventilator for every 600 square feet of insulated ceiling.
This balances the chimney effect and makes ventilation more efficient due to the joint action of the soffits and the Maximum ventilator. Drawn air enters and circulates evenly; the ventilator then uniformly exhausts excess humidity and heat from both sides of the roof.
To correct this problem, Ventilation Maximum recommends the installation of an additional ventilation duct with a roofcap to direct the flow of warm air outside away from the roof and at a suitable distance from the soffits. This prevents the possibility of hot air melting the surrounding snow which could cause an accumulation of ice.
This type of building requires installing a Maximum ventilator for every 600 square feet of insulated ceiling.
It is necessary to keep soffits unobstructed and to ventilate from the roof’s peak to maintain even air circulation. Install a Maximum ventilator model # 301 for every 600 square feet of insulated ceiling.
An insulated air duct is therefore installed along the whole length of the roof’s gable. This will ensure sufficient ventilation between each roof joist. Air is drawn in through the soffits between each joist and is consequently evacuated by the Maximum ventilators.
The ventilator heads must be uniformly levelled: they must be installed at an identical height. Never install two different models on the same roof. Never install a Maximum ventilator close to a parapet, a wall or an adjacent device that is higher than the ventilator.
N.B. A ventilator should never be installed any closer than 4 feet from a wall or unit which is as high as the ventilator itself. N.B. The opening within the wooden curb will determine the Net Free Ventilation (NFV) for model # 101 and # 102. N.B. It is important to measure the free air space between the underside of the roof deck and the insulation to determine the right model of ventilator. It is also important when ordering these ventilators that the size of the wooden curb (exterior), as well as the thickness of the roof membrane being applied on the wooden curb be considered to ensure the right dimension of the ventilator.
If the heating ducts have been insulated; no duct should be left bare.
If the vapour barrier has been built in.
If attic insulation conforms to standards.
If an attic access door or partial wall has been insulated according to standards.
The presence of outlet dampers for clothes dryer, range hood and bathroom exhaust. Ventilation Maximum offers a selection of single or multiple gravity outlets.
Choose a ventilator that is adequate; avoid seemingly comparable substitutes that have not been tested nor approved by a reputable firm for their drawing and exhausting capacity, durability and safety features.
Be sure that all the points mentioned above have been verified.
Choose the ventilator suitable to the building’s specifications, according to the standards and recommendations of the manufacturer Ventilation Maximum.
Install the ventilator that is adequate for the specific location, the head being exposed to all directions of wind and the louvres rising above the peak of the building by 6 inches.
The base of the ventilator should be well weatherproofed.
Make sure that the soffits are opened and that no insulation is blocking them.
Make sure that all openings, other than the Maximum ventilators and the soffits, are completely closed in order to create good air circulation from the soffit to the peak where the Maximum ventilator is located, ensuring totally efficient attic ventilation.
None of the exhaust vents such as for the clothes dryer, range hood, or bathroom ventilator should discharge into the attic or near the soffits.
Avoid installing a ventilator near a parapet, wall, or a device that is higher than the ventilator.
Make sure that the ventilator will never get covered by snow, or that snow cannot accumulate up to the level of the deflectors, so as to prevent all risks of infiltration in the unit. If the snow accumulates up to the deflectors, it will slide right above the storm proof deflector and enter the unit. You might have to shovel the snow around the ventilators during those years with considerable accumulations of snow, or add extension pieces on the units so that they are always above snow level.