Addition Question: Venting Roof/crawlspace - Building & Construction - DIY Chatroom Home Improvement Forum


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Building & Construction

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

Reply
 
Thread Tools Display Modes
Old 11-22-2008, 04:17 PM   #1
Newbie
 
Join Date: Nov 2008
Location: NH
Posts: 17
Rewards Points: 10
Default

Addition Question: venting roof/crawlspace


Disclaimer: I am not a carpenter. I'm just trying to get rid of an ice damming issue.

My house was built in the 40's as roughly an 18'x18' structure, 2 story, no attic. Roof is like a 12 in 12 pitch? [looks 45 degrees to me.] Shortly after that, a 12'x18' single story (with a short crawl space above) addition was added. The roof for this part is more shallow, like 30 degrees. Anyhow, I have issues with ice damming on this "new" roof, due to ventilation: this roof has a single 4"x6" vent.

Now, at the end of the original rafters there is fascia, untouched after all these years. The previous house owner redid most of the interior, including insulation and sheetrock; he did put the pink foam tray under the roofing and a ridge vent. On the original portion of the house, that is. The addition has the old crawlspace, untouched basically. The crawlspace is insulated from the rest of the house; it cannot vent into the venting on the steeper roof; as a result, this roof isn't vented either (no air intake).

My question is: can I drill holes into this fascia, so as to allow venting to occur? This isn't some form of fire blocking? I have to go get a photo of the crawlspace, but below are exterior photos.

Photos:
Back of house, faces east:


Side of house, with leak, faces south:



Front of house, faces west:



Last side of house:

Advertisement

supton is offline   Reply With Quote
Old 11-22-2008, 04:57 PM   #2
Newbie
 
Join Date: Nov 2008
Location: NH
Posts: 17
Rewards Points: 10
Default

Addition Question: venting roof/crawlspace


Crawlspace, as attached. You can see the original siding, which was white; looks like they nailed a support across that to support the new rafters. If you look above that, you can see the blocking (old fascia?).

on edit: the hole in the bottom right is the crawl space entry. The backside of the original siding is all insulated (you can see a bit of insulation in the entry); not shown is the batting that I'm laying on to take this photo.
Attached Thumbnails
Addition Question: venting roof/crawlspace-crawlspace2.jpg  

Advertisement

supton is offline   Reply With Quote
Old 11-27-2008, 03:50 PM   #3
Newbie
 
Join Date: Nov 2008
Location: NH
Posts: 17
Rewards Points: 10
Default

Addition Question: venting roof/crawlspace


Today I removed that blocking. I think it was installed either as fireblocking, or to just prevent airflow. In some places it was held in with just a nail, so I don't think it was installed for structural reasons.
supton is offline   Reply With Quote
Old 01-21-2009, 12:24 PM   #4
Home Improvment Contactor
 
Join Date: Jan 2009
Posts: 35
Rewards Points: 25
Default

Addition Question: venting roof/crawlspace


If you want to just ventilate the addition attic space. Add a couple roof turbines or soffit vents. I don't think this is causing your problem. Pitch is. Also is it damming at the point where the 2 roofs join or at the bottom of the addition roof?
Jack of most is offline   Reply With Quote
Old 01-21-2009, 06:37 PM   #5
Newbie
 
Join Date: Nov 2008
Location: NH
Posts: 17
Rewards Points: 10
Default

Addition Question: venting roof/crawlspace


It was damming in the middle of that shallow pitched roof.

It seems to be doing better this year, after I removed the blocking. There was a storm or two that I could not get up there until a day or so later; when I pulled the snow off, it was still fluffy on the bottom. I still pull the snow off, though, after each and every snow storm.
supton is offline   Reply With Quote
Old 01-22-2009, 08:05 AM   #6
Home Improvment Contactor
 
Join Date: Jan 2009
Posts: 35
Rewards Points: 25
Default

Addition Question: venting roof/crawlspace


I'm not positive, but by removing the blocking you may have opened up enough space to allow a little warmer air into that attic space keeping it from damming.(melting just enough) Or, just the opposite, cooling off that space reducing the temp difference in that attic as to not melt snow/frost to turn into ice when temp drops.(the reason the snow was still soft this year) Sun can cause this problem also. Warming the roof during the day and freezing at night.

The way it's supposed to work is; the attic spaces of a house are to be the same temp. as the outside temp. They should also have at least 150 sq. inches of ventilation.(Depending on your local building codes)

Insulate your living space from the attic with the recommended R value for your area. It pays to insulate. I think 25 - 30 is good.

This should help but I still feel that pitch is the problem. The reason for steep roofs in northern climates. I used to have to shovel low pitched roofs on the farm as a kid.
Jack of most is offline   Reply With Quote
Old 01-22-2009, 07:33 PM   #7
Newbie
 
Join Date: Nov 2008
Location: NH
Posts: 17
Rewards Points: 10
Default

Addition Question: venting roof/crawlspace


Well, there is a 4"x6" gable vent in the crawlspace, so there is some air intake, just not good enough. I might look at making it bigger, and adding a second one to the other wall; but as you said, it's shallow. I suspect that, as long as i keep the snow off it, I should be all set. I simply cannot get any airflow from the eves without ripping out the ceilings, and I'd prefer not to do that right now.

Advertisement

supton is offline   Reply With Quote
Reply


Thread Tools
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
Question about dryer venting jimithing78 HVAC 10 08-26-2008 12:37 PM
Flat roof venting question vendejp Roofing/Siding 8 07-17-2008 04:45 PM
Venting question. Bcoleman6 Plumbing 7 03-21-2008 04:41 PM
Question: second story addition to existing room elmorem@gmail.com Building & Construction 3 02-17-2008 10:38 PM
Having Addition built- question on footings joshjani Building & Construction 1 07-21-2007 07:03 AM




Top of Page | View New Posts