Quick guide to roof vents

Ventilation is critical when it comes to attics. Ventilation is needed as moisture is gathering due to human activity. Inside a building this is not very harmful as most of the year the inside of a house is warmer than the outside and almost all the moisture is retained in the air. In attics though the situation is different as the conditions change more dramatically as seasons pass. This is where roof vents come through to save the day.

Roof vents come in a wide variety of shapes and technologies all of them suited for different purposes. Static vents are those roof vents that do not have any mobile part. Practically they are just some glorified holes in the roof. As moisture tends to rise up it is best that they are situated on the very top of the roof. Also they should be given the appropriate kind of flashing otherwise you might get a radically different type of moisture when it is raining.

Power ventilators are a more advanced type of roof vents. In principle they use the a turbine to catch the wind which in turn will help the air from the attic being sucked out. All sounds reasonably fine, but as with all alternative sources for energy, you must take into account that the wind will occasionally stop… mostly during summer… when the heat will all but melt you… You get the picture.

The fan driven ventilators use electricity to drive out the old air from the attic. Reliable, expensive and an additional item on your electricity bill.

Altogether I still recommend the static vents. The best subtype available are I think the ridge vents. They are located on the very top of the roof along the ridge, hence the name.

Typically government regulations will take into account the amount of ventilation needed during winter, but let's be honest humidity may be nuisance but it is nothing compared with the summer heat. Typically for the later you will need better roof vents.

When estimating the ventilation needs you must know the volume of air that your attic holds. This is not as complicated as it sounds. First you need to measure the area of the attic. If your house has a non regular, weird shape divide the surface into rectangles and measure the width and length for each one of them. For every rectangle you have multiply the width with the length then add up all the numbers and voila you have the area. Next you need to measure the height of the attic, this is a pretty straightforward task and it won't need any hard calculations. Now to find out what volume your attic has multiply the area with the height and then divide the number with four. That's it. Well not quite it. Make sure you use the same measurement system while you measure.

Fine now we know what volume of air our attic has and we are one step closer to find out what are our ventilations needs. Now it is the time to introduce another term. Let me introduce you the FVA. Confused? Probably. FVA stands for free vent area. This is something that the manufacturers will provide you when they will sell you the thing. No measurements involved. By using these factors you can safely decide how many roof vents you need.

As a side note the volume of air from the attic should be replaced every six minutes, especially during summer time. If you're your has a dark color and is not sun reflective, than you will most likely need an even better rate.

Now enough theoretical applications let's put those vents to work. Here I will show you how to install a ridge vent. Pick up the instructions from the manufacturer and read them carefully. This is because depending on the manufacturer the instructions may vary. All of these vents have their own patented weatherproof technologies. Now that you have the specifics it is time to make the hole. First remove the ridge shingles in the place where the instructions advised you. Clean the place from that loose paper and loose nails. Use a circular blade to remove cur the sheathing along that line. Again it is best to clean the place from all that debris, loose nails, you name it. Keep organized so you do not transform everything in one big mess. Now carefully put those vents into place as the instructions say. Hopefully in the end you will get a nice set of ridge vents, if not you will have a nice set of holes in your roof. Either way ventilation accomplished.

Now if ridge vents still don't suit here are the instructions to install fan driven vents. As I said earlier these require electricity and are usually frowned upon by any decent person with concerns to the power consumption. But, oh well, desperate times need desperate measures. First you need to find a place to fit it. Between two rafters will be perfect. Cut the shingles to make a hole and clean the mess, including the loose paper and the nails. Then using a circular blade to cut a hole through the roof with exact same size as the throat of the ventilator. But the ventilator into place, make sure that you do some serious exterior flashing, plug the damn thing and turn it on. Ahh… Summer breeze at the touch of a button. You gotta love it.

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