ridge vent

[MarkAndDebbie]

Is this cut OK for getting the ridge venting?

That is ... when cutting my rafters, I don't cut to the corner. Leaving a half inch of rafter not plumb. That way the sheathing will not touch the ridge (giving me a vent at the ridge).

I don't really need this yet because my shed (current practice project) won't be insulated/ ceiling finished. But I wanted to practice the way the house would be.

Thanks,
Mark

BTW - metal roof.

[PEG688]

Just cut your sheathing 1  1/2 " short of the ridge center beam , no added cuts to the rafters.  Metal roof you can cut the sheathing 2" short .  Use a good core vent made for metal roofing , metal ridge vents have been known to leak in wind driven rain storms.

If you have a tallish standing seam roof all the more important that the venting strip touchs in the "valleys" of the standing seam.

[MarkAndDebbie]

Just cut your sheathing 1  1/2 " short of the ridge center beam , no added cuts to the rafters.  Metal roof you can cut the sheathing 2" short .  

So I calculated the roof sheathing to be 12' (3 sheets) ridge to eave. So I thought I might avoid cutting them all together. Assuming I am plumb, square, and have no twist, cup, etc in the ridge or rafters

But I wondered if a standard ridge cap/vent thing would fit if I did that. It seems it would be 'wider' than what you mentioned ~3" instead of ~2.

I can do it either way. I was looking for the easiest solution that wouldn't bit me later.

Thanks,
Mark

[glenn kangiser]

Some ridge caps are quite wide.

We used to have about a 4 to 6 inch gap with about a 12" wide ridge cap.

[PEG688]

 So Glenn that big gap on a house? Or a pole barn?

The big gap IMO can create a few different problems ,

#1 : Rain , wind blown = leaky roof= bad

#2: Big gap = birds , bees ,  rats , bats etc all can get in .  Sure if your roof is a steep pitch and no trees are around the crawlers , rats may not get in BUT this past winter we spent a bunch of hours , read $$$$$ taking all the insulation out of a attic , screwing on from inside the attic heavy hardware cloth ( read 1/4" mesh wire ) due to Norwiegn rats eating the lighter nylon "Big screening) under a meatl roof ridge cap , hip roof lots of trees , tree hugger / bird , squirell , racoon , etc etc feeding gun toating home owner. The feed drew the rats the trees gaveum access. Dag things either eat the sheetrock or make beds in it , they hard dug out LOTS of little holes  a few came thru the paint in the bathroom which is how they where  found out.

#3: The bees , birds also love a opening  air does not need mile of opening to flow out of , critters have may have a harder time finding a smaller hole.

#4 : All that calcuating your dooing know is good theroy , you'll see what ya really have when ya get there.

I leave a 1 1/2" slot each side , no leaks , no rats , etc etc . YMMV.

Good luck , PEG    

[Ernest T. Bass]

We've been debating whether or not we need to install box vents in our metal roof.. A ridge vent wasn't an option for our particular type of roofing. We have a vaulted ceiling, with about 4'' of ventilation space between the insulation and the metal roofing. Also, our ceilings do not run up to a peak in the inside, if you know what I mean.. We have ties near the top of the rafters, and a miniature attic type space above the insulation there. We have vents all along the soffits of the roof, and a good vapor barrier on the inside. Taped all the seams as best as we could.. Our roof is just a simple gable, 44' long at a 10/12 pitch.

I would feel better with the added ventilation of the box vents, but really hate the idea of cutting into our industrial-grade, standing seam metal roof.. All of the panels are pre-caulked and crimped together, so replacing a single sheet that you accidentally cut the wrong sized hole in is close to impossible. Very, veeery close to impossible...  :-/

[glenn kangiser]

PEG, that gap was on our steel buildings with optional 10' ridge vents able to be placed anywhere.

The ridge cap all had die cut rubber closures on both sides and it was screwed down under the cap.  We never had any problems with it.  

It may not apply so well to a house.

[glenn kangiser]

We've been debating whether or not we need to install box vents in our metal roof.. A ridge vent wasn't an option for our particular type of roofing. We have a vaulted ceiling, with about 4'' of ventilation space between the insulation and the metal roofing. Also, our ceilings do not run up to a peak in the inside, if you know what I mean.. We have ties near the top of the rafters, and a miniature attic type space above the insulation there. We have vents all along the soffits of the roof, and a good vapor barrier on the inside. Taped all the seams as best as we could.. Our roof is just a simple gable, 44' long at a 10/12 pitch.

I would feel better with the added ventilation of the box vents, but really hate the idea of cutting into our industrial-grade, standing seam metal roof.. All of the panels are pre-caulked and crimped together, so replacing a single sheet that you accidentally cut the wrong sized hole in is close to impossible. Very, veeery close to impossible...  :-/

Air would definitely move through better if you currently have nothing up there.  It comes in the soffits - heats - rises but sounds like no where to go if no ridge vents.

[Ernest T. Bass]

Yes, that is my concern.. There are vents in the soffits on either side of the house, at the peak, though. Would this cross-ventilation disperse the air up there?

[PEG688]

Yes, that is my concern.. There are vents in the soffits on either side of the house, at the peak, though. Would this cross-ventilation disperse the air up there?

I  take it thats NONE at the peak?  Bad deal , you could be setting up for mold under the sheathing ,could you add gable end vents in that little attic space you mentioned ? That would be better than nothing.

[Ernest T. Bass]

I keep messing up my train of thought, jumping back and forth on these topics...  

At least we're still talking about vents... That makes it easier. Yes, I wanted to put gable vents on the....gables. But it ended up being easier just to put a few more soffit vents in that area, and I think they do the same job.

We have no solid sheathing under the metal. I suppose that could lead to frost if any vapor made it's way up to it.. Like I said, we did the best job we could on our vapor barrier, but I'm just not sure what to expect with all of this...

[PEG688]

 Gable ends Ernest , the peak area of the end wall.  Those soffit vents your taking about are at the eaves right ? Where your gutters and facia boards are ?

Do you have enclosed rake soffits? The part of the roof following the rafters up the slope?

You may be mixing and matching different terms which is confusing the hell outta me  

 A gable end vent goes in the side wall up by the roof peak , one in each "gable end wall" .  


Gable end vent above the front door and bay window , octagonal shaped .



Is that the type vent you mean?  Or similar.

[glenn kangiser]

You are talking soffit vents at the top of the gable? :-?

Is your ridge vent sealed tightly or can it vent under it too?  Did I fail to read close enough? :-/

[Ernest T. Bass]

Ok, yeah, I'm mixing my terms up... Darn, it's just so unprofessional of me.  

Vents in the "enclosed rake soffit" is what I meant all along. (We have vents at the eves as well.)

[PEG688]

You are talking soffit vents at the top of the gable.  

Is your ridge vent sealed tightly or can it vent under it too?  Did I fail to read close enough? :-/

Yes , Maybe , I Think , ah well no , ah , ahahhhaa :-/  :'(   :'(  

[glenn kangiser]

Think nothing of it --- helps PEG a bunch but I'm lucky I remembered it was called a gable.

[Ernest T. Bass]

You are talking soffit vents at the top of the gable? :-?

Is your ridge vent sealed tightly or can it vent under it too?  Did I fail to read close enough? :-/

No fair! I can't type fast enough to keep up... (All the letters on the keys are worn off... A real pain. )

No sure what you mean about the ridge vent.. We have none. The ridge cap is sealed tightly.. Every joint is caulked with butyl tape. The j-channels at the ridge accept the roofing panels, and the cap comes down over the tops of the j-channels.

[glenn kangiser]

I'm stupid -- I meant ridge cap. :-?

We used to have a flat ridge cap that only contacted the tops of the high ribs.  Rubber closures were used to seal between the flat cap and the low part of the sheet.  Removing the rubber seal could create a vent space that could be screened if desired.  We usually installed a big 10' ridge vent over the top of the ridge on shops though.  

[Ernest T. Bass]

Well, our particular metal roofing has 3'' high ribs, so you'd be asking for a lot leaking if you did that...  :-/

[glenn kangiser]

Yeah - there are a million types of roofing - different situations and remedies for each one.

How about a ventilation cupola?  Probably wouldn't fit your scheme.

[Ernest T. Bass]

Mmm.. Yeah, we're not typically picky people when it comes to looks, but I don't think it would work...  :-/

Thanks for all the help! Gotta be duckin' out, though.. 2:00 am is about all I can handle.  

[PEG688]

#1:  We have a vaulted ceiling, with about 4'' of ventilation space between the insulation and the metal roofing. Also, our ceilings do not run up to a peak in the inside, if you know what I mean..

#2: We have ties near the top of the rafters, and a miniature attic type space above the insulation there.

#3: We have vents all along the soffits of the roof, and a good vapor barrier on the inside. Taped all the seams as best as we could.. Our roof is just a simple gable, 44' long at a 10/12 pitch.

#4: I would feel better with the added ventilation of the box vents,

Start here Ernie

#1: You do have acontinous path for air venting in that 4" space , thats good .

#2: That little attic could you add a vent in both gable ends that would allow cross venting of that space?  If so your golden as the soffit vents will allow  air up the added "gable end vents " will allow air out perfect , almost flow. Doable 8-)  

#3: You have soffit venting at the eaves , thats good , air can flow over the insulation up to the peak into that now gable end vented attic space .

#4 : Whats a Box vent?   Do you mean a roof jack / vent??  

 

[Ernest T. Bass]

I'm not sure if they're typically called "box vents", but I'm just talking about those square vent units that put down over a hole in your roof..

As far as the gable vent goes, we only have about a foot from the top of the insulation to the ridge beam. On the gables, we have 8x8 posts centered in the walls, supporting the ridge beam... With that post in the way, there's little room for a vent, even a smaller one on either side of it..  :-/

[PEG688]

They're called roof jacks , at least thats the right most common  name for them ,




 Back to your lil attic , [highlight]ANY[/highlight] air flow you can get thru there is better than none. Even if those vents are small , or you build a bump out say a couple of inch's to accomdate the projection on a triangular type gable end vent to miss that ridge post would be a improvement.

 

Link : http://www.architecturaldepot.com/c/gable-vent-triangle/


That one does not appear to be adjustable , but if you hunt around you'll find one , you should vent that space, but thats up to you.

G/L PEG

[Ernest T. Bass]

How easy would it be to fashion those gable vents from wood ourselves?