gable vent (bats!) - Attic ventilation

[Rich]

A few years ago, I found a small colony of bats living in the gable vent of my house. The bats could make their way into the attic through small holes where the screen was stapled to the wood vent.

After they left for the season, I took out the gable vent, attached screening to the outside, and made it impossible to get back in. This seems to have worked fine.

I'm about to have my house vinyl sided and I'm thinking of having the gable vent closed up with plywood and siding over it. I really do want to deal with bats or other critters getting in.

My house is 12 years old. I have soffit vents, ridge vent, and a power temp controlled roof vent (I had that put in when I had central air installed).

Many/most of the similiar homes in my neighborhood do not have gable vents. Does it sound like I have adequate ventilation in the attic if I remove the gable vent? There is no gable vent on the opposite gable (chimney on that side).

Thanks

[m Ransley]

You will not know if the venting was needed unless you do calculations on what you need . Even then overventing is better. I hope you do not run the power vent in winter or much in summer. They do pull up and out conditioned air.

[newsgroups01REMOVEME]

this is usually the case when the fan is over sized for the attic inlet air flow. But a very good point that should be known by anyone that is thinking about installing an attic powered vent system.

later,

tom @

[Roger]

I would keep the gable vent. It is easy to keep varmits out of the attic, but difficult to add a vent once you cover it.. A sturdy 1/4 inch galv. screen hand-stapled to the interior is what you want. Don't use the tiny staple gun staples, but the 3/4 - 1" galv. staples. If you have hot summers, keep the vent, in any case.

[Rich]

The power vent only runs in the summer. I forget what I have the thermostat set to, but it is pretty high.

Since I was one of the very few people in my neighborhood to ask the builder to put the gable vent in in the first place (heck...my dad has one...of course I want one!), I thought that it may have been overkill in the first place. As you mention, I'm sure it is better to overvent, I just don't want to deal with bats again.

m Ransley wrote:

[RBM]

[RBM]

[willshak]

On 12/14/2004 5:23 PM US(ET), Roger took fingers to keys, and typed the following:

I didn't have bats, but I did have many paper wasp nests between the louvers and standard window screen that was tacked to the 2x4 box frame around the square vent. I wanted to keep flying insects from entering my attic, but I had left too much room between the louvers and screen (3-1/2"). They didn't get in any further than the screen, but there were so many nests that they might interfere with ventilation. I wanted to install a thermostatically controlled power vent, so before installing it, I just removed the screen and about 20 nests, and then moved the screen to lay flush against the inside of the louvers, and secured it with pieces of lath stapled to the sides of the 2x4s.

[Rich]

Snakes in the ceiling!! I hope my wife isn't reading this thread. Everytime the house makes a settling noise she'll be screaming her head off and telling my to buy a pet mongoose!

Thanks for the info. The new gable vent will definitely not be made of wood, so maybe that will make the difference.

Thanks again.

RBM wrote:

[Rich]

Thanks Roger,

The problem is, the gable vent is directly above my side door. When the bats were up in the gable vent, the bat guano would fall directly on the stairs to the side door. That is how I found out about them in the first place. Your suggestion would definitely keep them from entering the attic, but I also need to keep them out of the front louvres all together.

From reading your post and others, it probably would be a good idea to keep the vent and try to think of a creative way of blocking there entrance.

Thanks.

Roger wrote:

[Bell]

Build a belfry. You know that all bats prefer the belfry.

[trader4]

If you have a continuous ridge vent across the roof and good soffit venting, there is no reason you can't eliminate the gable vent. In fact, there is debate over whether having gable vents with ridge vents actually makes things worse. Some are of the opinion that the gable vents allow a short circuting effect, where air enters from the gable and exits throught the ridge vent, rather than allowing air to circulate all the way up from the soffit vents to better cool the attic. Plus, if you calculate the square footage of the gable vent, it should be small compared to the area of the ridge vent. And finally, you have a power vent as backup, with of course, the same potential short circuiting issue. I'd make sure the soffits are sufficient for the rating of the fan to avoid sucking conditioned air out of the house.

[Rich]

You bring up a good point. I never thought about the short circuiting affect. My central air installer recommend installing the power vent on the roof (about 1/2 way up the side of the roof). Considering I have a ridge vent, am I doing more harm than good by having the power vent?

Thanks!