Bathroom Venting

[Robert Adams]

One nail in each side of the ridge beam isn't overcoming the " huge loss of integrity"

         It's allot more loss of racking resistance and rafter pull away prevention than you might think. It's a minimum of one fastener lost every 16" and most use allot more nails than that. Ever seen what happens to rafters of a house that was built with cedar shingles over time? The rafters will pull away from the ridge, sheeting the roof prevents that as it adds allot of strength.

[CLETUS]

          Ever seen what happens to rafters of a house that was built with cedar shingles over time? The rafters will pull away from the ridge, sheeting the roof prevents that as it adds allot of strength.

I have a lot more experience with trusses than I do with rafters... However, I thought that was the purpose of a collar tie?

[Robert Adams]

I have a lot more experience with trusses than I do with rafters... However, I thought that was the purpose of a collar tie?

I have very little experience with trusses as they aren't used in residential and very little commercial. It's nearly impossible to do trusses for the style of roofs on houses here. Few houses are square here and most are built with very steep roofs. The only trusses I have seen here are on 70s houses and even then it's rare. Labor is cheaper than trusses. I wish our 1960 boxy house had trusses.

 Collar ties are meant for wind loading. I would like to see a tie just below the peak and attached to the ridge but that won't happen. I just like things as strong as you can get them.  Stick framed roofs are usually pretty scary like a bunch of popsicle sticks thrown up there with a few nails.


        My parents house was built in 84 and in that time everything got a cedar roof. They had the roof replaced years ago and ridge vent installed and soon after I noticed the gaps when I was in the attic. I went in and braced everything at the peaks and added a few vertical supports as the plywood and asphalt roof is much heavier than the cedar was.

[Snipe Hunter]

I'm wondering if the ridge vent was cut in when the roof was replaced.  If so, then I don't have any problem blocking off the rest of the existing gable vent minus a 4" hole for the vent...but I'd be a little worried if the original builder/architect planned for it from the beginning and here I am messing with that.

 

Considering when the house was built: If you have the cardboard baffles between all joists, it's a pretty good bet they've been there since the house was built. Late 80's is about the time soffit/ridge venting became code requirements.... at least in this area. In this area, roofers are required to add a ridge vent when the roof is replaced. But they aren't required to add continuous soffit venting.

You might have a home where the Architect originally designed the attic space with gable venting but the jurisdiction required soffit/ridge venting by the time the house was built so the builder did it without changing the drawings and just left the gable vents.

[Snipe Hunter]

I have a lot more experience with trusses than I do with rafters... However, I thought that was the purpose of a collar tie?

To balance the roof load... Snow, wind, roof coverings etc. They're intended to prevent rafter-spread.

Ever seen a ridge line that dipped "like a smile" in the middle? Chances are it's a rafter roof with poor venting. Either without or failed collar ties or not enough collar ties.

I was in an un-vented roof (just one small gable vent and one small roof vent) and the ridge dipped about 4" in the middle. This was in an attached garage which was added to the house. The sheathing was molded but not delaminated. The collar tie nails had rusted through and had fallen onto the ceiling joists. From the ground, I could sight along the exterior of the building along the soffit and see that the center of the garage addition had "bowed" outward a few inches on both sides. The end of the ridge connecting to the house had pulled away from the house and was leaking water into the framed chimney chase. The wood was rotten in the framed chase and I could see mold on the wet sheetrock on the framed chase. I did a reinspect after it was fixed. The contractor used come-alongs in the attic and pulled the walls back parallel to each other, installed new collar ties, ridge and soffit vents and insulation. They re-framed and sheetrocked the chimney chase and remediated mold. hey obviously had done it before. All because of poor attic venting.

[brnhornt]

Considering when the house was built: If you have the cardboard baffles between all joists, it's a pretty good bet they've been there since the house was built. Late 80's is about the time soffit/ridge venting became code requirements.... at least in this area. In this area, roofers are required to add a ridge vent when the roof is replaced. But they aren't required to add continuous soffit venting.

You might have a home where the Architect originally designed the attic space with gable venting but the jurisdiction required soffit/ridge venting by the time the house was built so the builder did it without changing the drawings and just left the gable vents.

Good point about the baffles meaning it was likely original!

I think based on what has been said I am still going to go with blocking off this gable...it seems likely not needed...and the south-facing one will still be there.  Anything I should pay attention to in the following months/years to make sure I didn't make some massive folly?

[brnhornt]

So I did a shocking thing and took a walk around the neighborhood. (it's about a 1 mile loop) and came across a couple of houses that were mirror copies of my home.  No ridge vents.  Roofs appeared to be in too good of shape to be original...but I'm definitely not an expert.  At the very least, it makes me comfortable enough to proceed with blocking up this gable vent and using it to vent this bathroom exhaust.

Thanks again all!
Kevin

[brnhornt]

If you decide to use a soffit vent with flex duct, use the metallic flex duct, not the plastic. The metallic has a lot smoother surface  and moves air better than the plastic.

I completely agree that I'd like to use rigid metal duct in this case to move the air better...I'm paying for the fan/cfm...why waste it with quick/easy ducting?
So is there anything wrong with getting segments of these:
https://www.homedepot.com/p/6-in-x-5-ft-.../100125106
An then cutting and wrapping pieces of batted insulation around them?  Or....do they make correctly insulated rigid metal ducting?  (my searches are turning up nada)

[brnhornt]

Ignore my last....did some more digging and have found duct sleeves.

[brnhornt]

Welp...just wrapped up.  Two days up in the attic...not bad...thankful for the cold front that has been pushing thru.

   

Thanks for the advice fellas!
Kevin