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Reservoir469

12:19PM | 03/17/04
Member Since: 03/16/04
4 lifetime posts
Bvbasement
Have a 2 year old colonial in NH and recently found mold and wet walls in the attic, mold was mostly in the middle to upper part of the decking toward ridge. Have continuous sofit vents (which are protected by baffles in attic) and ridge vent and blown in insulation, but I believe the ridge vent is not pulling/exhausting air enough. That fabric material in the ridge vent seems to flat and gets covered with 8" of snow, how can it ventilate? I put in two 12x18 inch gable vents on both sides up as high as possible. Things seem to be drying and the temp is now much lower, but humidity is still high. I am thinking that's because the wood is drying out. Don't you think the gable vents will contribute to more air circulation to the ridge versus canceling out the sofit vents? thks

devildog

06:25AM | 03/18/04
Member Since: 09/16/02
250 lifetime posts
I'm not a builder or anything like that BUT.

When they blew the insulation in did they put things that keep the soffit vents from being covered. When you're in your attic you should be able to see them. They're nailed or glued right to the underside of your roof and probably go about 1 foot above your insulation. If you can't see, is the insulation blown right to the edge of the attic? That may be your problem. You don't have the air circulation that you need. You have the ridge vent, that is where the warm air leaves. The cold air needs to come in from below. Check it out.

homebild

12:30PM | 03/19/04
Member Since: 01/28/03
693 lifetime posts
First, it is entirely likely that your ridge vent is not operating properly. It has been found that certain types of ridge vents, especially the fabric or mesh types do not do what they were designed to do and will eventually clog with soot, dust and debris making air flow next to impossible.

That said, it is never proper to install gable vents when any type of ridge vent is present since the presence of one defeats the purpose of the other.

The BEST solution in your situation would have been to replace the ridge vent, but now since you have installed gable vents, the proper course of action is to eliminate the ridge vents and use only the gable vents.

Next order of business is to find the source of excess moisture and eliminate it.

Are your bath vents properly vented to the outside? Dryer vent proeprly vented to the outside? No open dirt crawlspaces or basement floors? No use of any unvented gas heaters or fireplaces? No excess cooking/boiling?

Reservoir469

05:16AM | 03/24/04
Member Since: 03/16/04
4 lifetime posts
Points well taken, only question is if the ridge vent is not functioning anyway, why remove it? If it is venting only a little, how could it pull enough to just draw air from the gable vents? thanks.

homebild

01:49PM | 03/24/04
Member Since: 01/28/03
693 lifetime posts
Well, it has not yet been established that the ridge vent is not working at all, has it?

And even if it (the ridge vent) is only partially functioning, this will diminish the effectiveness of the gable vents and vice versa.

Your only serious options at this point are to:

1)Remove or completley block the ridge vent in favor of the gable vents

2)Remove or completley block the gable vents

and replace the current ridge vent with a fully functional non-blockable ridge vents such as can be found here:

http://www.airvent.com

http://www.lomanco.com

Reservoir469

07:30AM | 03/25/04
Member Since: 03/16/04
4 lifetime posts
Have read article from architect that adding gable vents in addition to ridge vent will not upset the air flow provided there is enough sofit ventilation. In my case, I have continuos sofit vents on both sides, attic nice and dry now..thks.

homebild

11:08AM | 03/25/04
Member Since: 01/28/03
693 lifetime posts
You would do well before to research the issue further before you commit to such advice because there is ample evidence in the Building literature to contradict such advice.

Here is on such example:

http://www.findarticles.com/cf_dls/m0NSZ/9_21/103123249/p1/article.jhtml

It should be noted also, that the amount of roof or gable vents necessary to vent the attic is directly related to the size of the attic itself.

For example, one formula suggests to have at least 1 square foot of roof ventilation for each 100-150 square feet of attic floor space.

For example, If you have a 60x30 foot ranch home, this equates to 1800 sf of attic floor space, and the need for at least 12-18 square feet or more of roof ventilation (1800 divided by 150 or 100)

The attic ventilation can be achived by adding 12-18 roof vents, about 24-36 linear feet of ridge vent or 12-18 square feet of gable vent.

The problem with the gable vent alternative, is that in order to create 12-18 sq feet of ventilation, you about twice as many gable vents as the typical 3 foot wide by 3 foot high vent can provide.

In short, most gable vents would not provide enough roof ventilation to adequately vent the attic space, and while soffit ventilation is helpful, roof ventilation is the most critical ventilation factor to be considered in the formula.

In other words, if the air can get in but cannot get out, you haven't solved the problem at all.

You should also research further because ventilation may only be a part of solving the overall problem.

If you have moisture being added to the attic that shouldn't be there, even with the proper amount of ventilation, the moisture will still be present.

Personally, I am not satsified with the architect's advice because the building literature contradicts it and there are other factors involved which are not ebing considered.

Luck.

LicensedWaterproofer

02:59AM | 03/26/04
Member Since: 03/05/04
301 lifetime posts
I really do not mean to crap on architects..but I have also seen them do some very strange things,for instance,an architect earlier this week has a crack/leakage problem in basement.One of his problem areas is a crack on his back wall....which was there prior to him building an addition on the outside of this back wall.He did not waterproof this area before erecting the addition...big mistake...he thought water would not "wick" underground...under the addition toward the back wall...wrong assumption! Also he does not have a deep enough footing to support the addition(he did work himself & only went 3 feet deep all the way around).So now(1 1/2 yrs later) the addition is dropping & pulling away from house! Anyway..to shorten this up..this is an architect!!! Who should have easily known better! Why do some people take shortcuts..to save money? Jesus..your going to wind up spending alot more in the end if you don`t take care of your problems correctly..just because someone is an architect/waterproofing/builder/inspectors etc doesn`t mean they have common sense! GL!
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