Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Roofing/Siding

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 01-18-2012, 01:36 PM   #1
Newbie
 
Join Date: Jan 2012
Posts: 2
Share |
Default

Attic Ventilation Issue After New Roof


We just had a new roof put on our 25 year-old colonial house, including a new ridge vent (Shingle Vent II). Attic is finished, with two access doors in kneewall on one side or room. While putting away Christmas decorations behind the kneewall, we discovered lots of moisture on the roof sheathing behind kneewall, and drips from nail heads onto attic subflooring. Never seen this before....After getting the roofer out to inspect, he said we need soffit vents installed to allow correct ventilation of roof, and to prevent heated air from being drawn into the unheated spaxce behind the kneewall (which is insulated). The previous owners had the attic finished, and the contractor did install stryrofoam proper vent behind the ceiling insulation, but it appears crushed, so not sure if I should proceed with installing soffit vents (was going to use 3 inch round), since there may not be adequate air flow behind the insulation up to the ridge vent.

Shouldn't the roofing contractor have informed us of the fact that without soffit vents, the ridge vent they were installing would not function properly?

How should I proceed to improve ventilation in my attic?

I also need to add insulation around the access doors in the kneewall and around some of the heating ducts hat feed the upstairs bedrooms which are visible and not fully insulated in the floor behind the kneewall in attic, to decrease air/heat flow into the uncondiitoned space behind kneewall.

Thanks,
PCinCT

PCinCT is offline   Reply With Quote
Old 01-18-2012, 01:49 PM   #2
Member
 
Join Date: Nov 2011
Location: Hartfield VA
Posts: 25,591
Default

Attic Ventilation Issue After New Roof


http://www.icc-es.org/reports/pdf_files/BNBC/97-22.pdf
A ridge vent is pretty useless without a soffit vent.
Did they install Storm and Ice shield at the bottom of the roof?
With out see what you have now it's hard to make suggestions, also we have no idea where your located.
Having uninsulated heating ducts in an unheated space is a great way for condinsation to form.

joecaption is online now   Reply With Quote
The Following User Says Thank You to joecaption For This Useful Post:
mae-ling (01-18-2012)
Old 01-18-2012, 02:08 PM   #3
Newbie
 
Join Date: Jan 2012
Posts: 2
Default

Attic Ventilation Issue After New Roof


Quote:
Originally Posted by joecaption View Post
http://www.icc-es.org/reports/pdf_files/BNBC/97-22.pdf
A ridge vent is pretty useless without a soffit vent.
Did they install Storm and Ice shield at the bottom of the roof?
With out see what you have now it's hard to make suggestions, also we have no idea where your located.
Having uninsulated heating ducts in an unheated space is a great way for condinsation to form.
Thanks for your reply - I am located in coastal CT.
Yes, they installed 36 inches of Ice and Water shield at the bottom of the roof. I can take pictures and post if that would help (I am new to this site, so may need some help on how to post photos).
PCinCT
PCinCT is offline   Reply With Quote
Old 01-18-2012, 06:16 PM   #4
Registered User
 
Join Date: Mar 2009
Posts: 9,968
Default

Attic Ventilation Issue After New Roof


Here you go: http://www.diychatroom.com/f98/

#3, and 4 down the list.......

"Having uninsulated heating ducts in an unheated space is a great way for condinsation to form."----- I think Joe hit the nail on the head, check for attic access door weatherstripping also.

Gary
__________________
If any ads are present in my answer above, I do not condone/support/use the product or services listed, they are there against my permission.
Gary in WA is offline   Reply With Quote
Old 01-18-2012, 09:40 PM   #5
Exterior Construction
 
Windows on Wash's Avatar
 
Join Date: Aug 2011
Location: VA, MD, DC
Posts: 5,544
Default

Attic Ventilation Issue After New Roof


Picture from outside would help as well.

Is there an overhang and enough for soffits?
Windows on Wash is offline   Reply With Quote
Old 01-19-2012, 08:50 AM   #6
Member
 
Join Date: Nov 2010
Location: Indianapolis
Posts: 84
Default

Attic Ventilation Issue After New Roof


Quote:
Originally Posted by PCinCT View Post
We just had a new roof put on our 25 year-old colonial house, including a new ridge vent (Shingle Vent II). Attic is finished, with two access doors in kneewall on one side or room. While putting away Christmas decorations behind the kneewall, we discovered lots of moisture on the roof sheathing behind kneewall, and drips from nail heads onto attic subflooring. Never seen this before....
If you didn't notice until the vent was installed, I'm guessing there is in fact an air space above the insulation, and the new vent is pulling more conditioned air through your access hatches which is causing the condensation.

Quote:
After getting the roofer out to inspect, he said we need soffit vents installed to allow correct ventilation of roof, and to prevent heated air from being drawn into the unheated spaxce behind the kneewall (which is insulated). The previous owners had the attic finished, and the contractor did install stryrofoam proper vent behind the ceiling insulation, but it appears crushed, so not sure if I should proceed with installing soffit vents (was going to use 3 inch round), since there may not be adequate air flow behind the insulation up to the ridge vent.
What size are your roof rafters, and what R value of batt insulation is stuffed in there?

Quote:
Shouldn't the roofing contractor have informed us of the fact that without soffit vents, the ridge vent they were installing would not function properly?
One would think, but it's not a fun job and nowhere as easy as cutting a slot and installing SVii. If you're thinking legal recourse, unless it was addressed in the contract I doubt you have a leg to stand on. You could, of course, not hire him again (I wouldn't).

Quote:
How should I proceed to improve ventilation in my attic?
Adding soffit vents can only help. A few 3" round ones here and there will do next to nothing for intake though. With SVii you have , IIRC, around 18" of net free area exhaust per linear foot. That would be 9 square inches per linear foot you'd need on both eaves, or in terms of round vents, three or four vents every foot.

Quote:
I also need to add insulation around the access doors in the kneewall and around some of the heating ducts hat feed the upstairs bedrooms which are visible and not fully insulated in the floor behind the kneewall in attic, to decrease air/heat flow into the uncondiitoned space behind kneewall.
Yes, you do. Glue a couple layers of rigid insulation to the back of the access door, install weather stripping where the door meets the jamb, and make sure it's tight when secure.

jmiller is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Attic ventilation - Have enough? Am I correct that there isn't much? darlingm Insulation 9 09-08-2011 04:11 PM
Another roof ventilation question Jim F Roofing/Siding 9 05-13-2010 07:51 PM
Finished Attic with Metal Roof jonathan03 Remodeling 3 05-13-2010 05:50 AM
Attic Ventilation in 1928 Bungalow stephensandlin Roofing/Siding 1 07-09-2009 11:16 PM
attic ventilation lou1968 Roofing/Siding 5 05-31-2009 09:33 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.