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Question about venting a shop attic, humidity, etc.

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Forum topic by Bertha posted 04-12-2011 02:12 PM 2770 views 1 time favorited 56 replies Add to Favorites Watch
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Bertha

13003 posts in 2159 days


04-12-2011 02:12 PM

Fellow LJ’s, I’d appreciate any input you might provide. When I purchased my home, it came with a small detached shop. The home inspector remarked that the attic space above the shop is sealed and that an access was recommended. I already had a list of repairs to submit to the seller, so I let this one go.

I went on to insulate the lower shop, new floor, new electric, etc. One day, when I was particularly brave, I recip’d a hole into the attic and peered in, expecting who knows what. It was empty, thankfully, just an uninsulated OSB ceiling. The soffets are perforated metal and I can see light peering up at me. Fearing that I needed to ventilate the space, I installed a centrally located turbine (a job I would not like to do again). I have a 50Qt. humidifier within the shop below.

My questions are, if it were your shop:
1) would you install a permanent drop down access and quit
2) would you insulate the attic and if so, with what kind
3) should I just tear out all the OSB and raise my ceiling a few feet (small stickering loft?)
4) have I already screwed up in some manner?

Any thoughts appreciated!

-- My dad and I built a 65 chev pick up.I killed trannys in that thing for some reason-Hog


56 replies so far

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racerglen

3112 posts in 2246 days


#1 posted 04-12-2011 02:37 PM

Al, how much space is in that attic ? if there’s enough for some storage then a drop down’s a good idea otherwise I’d just put a hatch in. Insulation’s a good idea anywhere, vapor barier with fiberglas bats over works for me, I’m thinking you probably get some hot summer weather, keeps you cooler as well as warm in winter. on item 3 I go back to how much space is above the OSB..? I don’t think much of that for a ceiling, drywall’s safer.. #4..think you’ve made the right moves so far

Glen

-- Glen, B.C. Canada

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Bertha

13003 posts in 2159 days


#2 posted 04-12-2011 02:52 PM

Thanks Glen, there’s not much up there, 3 feet at the peak at most. I could slide a few boards up there but I don’t think it’s worth fighting with OSB to gain a small bit of storage. It looks pretty standard, so your pre-cut bats might be just what I need. Thanks again!

-- My dad and I built a 65 chev pick up.I killed trannys in that thing for some reason-Hog

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grittyroots

53 posts in 2156 days


#3 posted 04-12-2011 06:32 PM

i would just put in a hatch to access. you could put a gable fan in that worksoff the rising heat. very easy to install

-- Gritty Roots i can build anything as long as i have 2 things the internet and my father-in-law

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Bertha

13003 posts in 2159 days


#4 posted 04-12-2011 06:37 PM

Thanks Roots, that’s what I’m inclined to do. I might even just build a hatch because the ladder my be a moot point, given that it’s barely large enough to crawl around in. I installed a wind operated turbine and it seems to move a good bit of air. I might consider adding a powered fan. Thanks again!

-- My dad and I built a 65 chev pick up.I killed trannys in that thing for some reason-Hog

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dbray45

3187 posts in 2242 days


#5 posted 04-12-2011 07:14 PM

You don’t want to put a vapor barrier in the ceiling, only the walls. You do want moisture to go up from the space below. I would put 19” of insulation in the ceiling but do not cover the vents in the soffits A roof vent or fan might be a good idea to keep the heat down in the summer.

-- David in Damascus, MD

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Les

201 posts in 2156 days


#6 posted 04-12-2011 09:29 PM

Check around your area for a company that blows in insulation for the local builders. They will put in cardboard folded in a v shape to prevent insulation from getting in the soffit area and still let air circulate. I had them blow in my shop attic to a R 42 and it was just a little more than the cost to buy the batts.

-- Stay busy....Stay young

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Bertha

13003 posts in 2159 days


#7 posted 04-12-2011 09:33 PM

Thanks Les! I even considered renting a blower from Lowes & doing it myself. I might die, of course, but I’d be saving a ton! To Not Very Good, I installed a turbine at the ridge, so there’s light coming through there. Prior to that, it looked solid as a rock. The house was built in 2007 and the roof looked great according to the inspector. I really wanted a tin roof but I’m not ready to trash a perfectly good roof for my sense of style. I haven’t yet had a humidity problem but I’d like to thwart it before it starts. Thanks to all above!

-- My dad and I built a 65 chev pick up.I killed trannys in that thing for some reason-Hog

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saddletramp

1098 posts in 2104 days


#8 posted 04-12-2011 09:33 PM

Al, it sounds as if you already have soffit vents and you have installed a turbine vent at the peak. All you sould have to do is install rafter vents to keep the insulation out of the soffits and then you can either blow in insulation or put down batts.

edit: Oops, seems as if I’m a post or two late.

-- ♫♪♪♫♫ Saddletramp, saddletramp, I'm as free as the breeze and I ride where I please, saddletramp ♪♪♪♫♪ ...... Bob W....NW Michigan (Traverse City area)

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Bertha

13003 posts in 2159 days


#9 posted 04-12-2011 09:37 PM

Thanks Saddle, do I require rafter vents if I’m using batts & stop them a tad short of the soffit? I imagine I probably do if I’m going to add any thickness of insulation. I’m glad to hear that I won’t have to paper the roof. I wasn’t looking forward to that :) Rafter vents look like they should be cheap. Are they? And does anyone know of the ideal spacing?

-- My dad and I built a 65 chev pick up.I killed trannys in that thing for some reason-Hog

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saddletramp

1098 posts in 2104 days


#10 posted 04-12-2011 10:18 PM

They are fairly cheap Al and they span the area between every pair of rafter from the soffit up for 48 inches. At least between every pair that has a soffit vent if you don’t have a continuous vent in mthe soffits.

-- ♫♪♪♫♫ Saddletramp, saddletramp, I'm as free as the breeze and I ride where I please, saddletramp ♪♪♪♫♪ ...... Bob W....NW Michigan (Traverse City area)

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Bertha

13003 posts in 2159 days


#11 posted 04-12-2011 10:21 PM

Thanks Saddle, I’ve got a continuous vent in the soffit, so I’m thinking a few between each rafters might keep the insulation from blocking the flow. I’m glad you mentioned this because I probably would have just piled insulation over them. After all, I managed to staple through some Romex when installing the wall insulation :)

-- My dad and I built a 65 chev pick up.I killed trannys in that thing for some reason-Hog

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saddletramp

1098 posts in 2104 days


#12 posted 04-12-2011 10:29 PM

Here is a link that will help explain how they are used and installed. It does mention both 24” and 48” vents but I would highly recommend the 48”. DAMHIKT

-- ♫♪♪♫♫ Saddletramp, saddletramp, I'm as free as the breeze and I ride where I please, saddletramp ♪♪♪♫♪ ...... Bob W....NW Michigan (Traverse City area)

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Bertha

13003 posts in 2159 days


#13 posted 04-12-2011 10:35 PM

48” it is. No link, but I’m sure I can find one quickly. Thanks again for the help. While I have you, do you prefer “Saddle”, “Tramp”, or Bob? :)

-- My dad and I built a 65 chev pick up.I killed trannys in that thing for some reason-Hog

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saddletramp

1098 posts in 2104 days


#14 posted 04-12-2011 10:42 PM

sorry about that here it is:
http://www.buildingforhealth.com/proddetail.php?prod=ADO-DV

-- ♫♪♪♫♫ Saddletramp, saddletramp, I'm as free as the breeze and I ride where I please, saddletramp ♪♪♪♫♪ ...... Bob W....NW Michigan (Traverse City area)

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saddletramp

1098 posts in 2104 days


#15 posted 04-12-2011 10:43 PM

You can call me anything but late to dinner.

-- ♫♪♪♫♫ Saddletramp, saddletramp, I'm as free as the breeze and I ride where I please, saddletramp ♪♪♪♫♪ ...... Bob W....NW Michigan (Traverse City area)

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