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-   -   Framing blocking vents (http://www.diychatroom.com/f9/framing-blocking-vents-135983/)

jsweney 03-04-2012 11:50 PM

Framing blocking vents
 
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New construction in Colorado. Approx 2100 ft^2 ranch + finished basement. Soffit + square vents near the apex and ridges of the roof. Can't say there's a one square foot vent per 300 ft^2 of roof area or not, looks a tad short on vents.

My inspector noticed the framing was partially blocking the vents.
Should I ask the builder to re do this somehow?
Or would it be better to move the vents and leave the framing as is.
Thank you very much!
Joe

joecaption 03-04-2012 11:56 PM

Picture shows nothing but a dark hole.
You need a ridge vent on the peek of the roof and soffit vents, no other vents are needed.

jsweney 03-05-2012 12:13 AM

Quote:

Originally Posted by joecaption (Post 870710)
Picture shows nothing but a dark hole.
You need a ridge vent on the peek of the roof and soffit vents, no other vents are needed.

The vents had not been installed at this point, you can see a temporary covering the openings where the vents are going to be installed. We do not have ridge vents. the roof here comes nearly to a point. there are soffit vents below. thank you.

titanoman 03-05-2012 03:56 AM

Your inspector should be able to tell you what you need to do, since he's the one that noticed it.

Windows on Wash 03-05-2012 07:45 AM

The framing is not tight to the roof deck in that picture so that is not fundamentally obstructing the vents.

Should be fine.

OldNBroken 03-05-2012 09:23 AM

I see the same thing as WoW

Windows on Wash 03-05-2012 09:26 AM

Quote:

Originally Posted by OldNBroken (Post 870898)
I see the same thing as WoW

Tough to tell from the pictures but that is how I see it.

If they are tight to the decking, relocate the framing members to either side or pop in another vent on the other side of the hip.

PAHome 03-05-2012 12:01 PM

It is a little hard to see from the picture but im not sure how much ridge you have for a ridgevent. If you have a hip roof and not much space for a ridgevent then you might want to consider a powervent. Powervents are very easy to install and come with a thermostat.

jsweney 03-05-2012 01:40 PM

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[QUOTE=PAHome;871000]It is a little hard to see from the picture but im not sure how much ridge you have for a ridgevent. If you have a hip roof and not much space for a ridgevent then you might want to consider a powervent. Powervents are very easy to install and come with a thermostat.



Thanks all! Not much room for a ridge vent. The new HVAC installers wanted $1000 for a solar vent, $300 for AC powered, which I thought was a bit over priced. Will re-consider shopping around for after closing. Here are a couple more low-res photos from my phone from today. The 3 vents in question are at the highest point of the roof. The only other vents are another 3 towards the garage. Builder thought the 1ft^2 net vent area (one entry + one upper) per 300 ft^2 rule sounded a bit excessive, but was going to check. There are continuous soffits around the house with shields to keep the blown in spun fiberglass insulation off.

Think I might just have the builder add another vent (for no charge to me). Moving the framing seems more problematic.

Thank you!

jsweney 03-05-2012 02:08 PM

Just emailed him and asked him to put one extra vent on the south exposure, near the top of the roof (same level as the other vents). In the roof photo I added today (sorry upside down) you can just see one of the 3 vents in question. The added vent would be on the south exposure towards the camera. Hope you all will agree this was a reasonable solution. Should make it easy to drop in a solar powered vent later.
Thanks!

jsweney 03-05-2012 02:14 PM

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zoom of roof top, you can just make out part of one of the vents.

Gary in WA 03-05-2012 02:52 PM

Either the framer or the roofer cut-in the 9x9" ? square vent hole, incorrectly. Because the framing is covering 1/3 of each, you would get the benefit of 2 full holes for NFVA. The sheathing is nailed to that hip framing= "Midwest Hip Framing"- third one down: http://www.allpan.com/res/FramingWithRoofs.pdf

If 9x9" = 81"sq. times 6 vents = 486" / 144" = 3.375" exhaust, your 2100' house / 300 = 7 sq.ft. / 1/2 for soffit, 1/2 for exhaust. Need 18 sq.inches.

Minimum requirements, if under the IRC:
R806.2 Minimum area. The total net free ventilating area shall not be less than 1/150 of the area of the space ventilated except that reduction of the total area to 1/300 is permitted provided that at least 50 percent and not more than 80 percent of the required ventilating area is provided by ventilators located in the upper portion of the space to be ventilated at least 3 feet (914 mm) above the eave or cornice vents with the balance of the required ventilation provided by eave or cornice vents. As an alternative, the net free cross-ventilation area may be reduced to 1/300 when a Class I or II vapor retarder is installed on the warm-in-winter side of the ceiling. From: http://publicecodes.citation.com/ico...006_par001.htm

So, if he installs 2 vents to replace the blocked 2 vents, you would only be short of the code by the 18sq.in. or about a 4"x4" hole. Only adds one vent = 81" + 18" = 99sq.in. or a 10"x10" vent. Why he didn't spread the exhaust vents out over the ridge surface area for optimum air-flow- rather than bunching them up for aesthetic reasons, I don't know.

Gary

dougger222 03-05-2012 05:36 PM

Like others have said air will still pass through under the truss/framing but it would have made more sense to have spaced 4 vents rather than 4 vents right on top of the trusses.

Not to make you any more nervous but I hope they set there depth at exactly 7/16 or 1/2in before they cut the vents out!

dougger222 03-05-2012 05:37 PM

Also,
I like turtle vents over ridge vent. On my rental I removed the ridge vent and installed turtle vents when it was roofed the first time.

jsweney 03-07-2012 03:47 PM

Quote:

Originally Posted by dougger222 (Post 871271)

Not to make you any more nervous but I hope they set there depth at exactly 7/16 or 1/2in before they cut the vents out!

Can you explain what the above means in some more detail please.


I drove by today, seems to have added 2 additional vents on the south face of the highest part of the roof at somewhat staggered heights.

Yes, it might have been better to space out the vents over the roof more.

Thanks for the help,
Joe


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