A different idea for a shop

[roypat2126]

Thanks Pat for your info. I had to sketch out your "invention" which is one of those "wish I'ld thought of that" things. You've got me thinking I might could increase the thermal air flow by adding soffit vents between each rafter on our typical brick ranch. It has end gable vents and a couple non-powered dome type vents, but it is HOT -hot in attic. Now on my barn (with 26x51 loft room ) I might employ your idea and add the additional supports in attic like in your Mom's porch. I have 2x4 scissor truss with top cord at 6-12 with 3-12 lower, and it has a nice cathedral ceiling effect. Once the metal roof goes on I expect increase in temp up there. But until I get the stairs done it ain't a problem. I suppose I could attach to the underside of top rafter cord a foil backed ridged foam (don't want to add too much weight ) and create a "plenum" about 2ft below the ridge running to the end gable vents...might need a fan in one...If this was done and I put in F/G batts on ceiling I'ld still need to vent the space between the batts and the underside of ridged foam...not sure how that would get vented perhaps I could circulate it through the shops below. I'll have to munch on this a bit. I answered my own question, I'm using 1/4x4" carriage bolts on the bander board (some call it "ledger") We get fairly high winds through here at times and I don't want the thing to blow off in a minor gust. I epoxed 1/2 anchor bolts in concrete slab for the 6x6 posts, so that is secure but I wanted the wall end to be as well...just don't trust 3/4" of nail to hold. Anyhow you've given me some avenues to ponder and I thank ya.
Have a blessed mediocre country weekend mi amigo,
rg

[Pat]

RG, You should consider a ridge vent. They are particularly well suited for the ducted chanel of the ventilated deck. Gable end vents are usually either too far away from the air inlet or too small or both and just don't move enough air to keep the "attic" temps down.

We are discussing solar energy mostly. The sunshine is causing the overheating. Harnessing the sun's heat to extract the sun's heat is effective and practical. As the problem intensifies so does the effort to clear the problem. It is sort of like the solar electric roof on my slide in pickup camper when we go to the desert. If the sun shines enough to make it uncomfortably hot then the solar panel makes more than enough electricity to run the swamp cooler.

A large funnel type ventilaltor (like on ships) but designed to rotate so that the open end is always pointing downwind will extract a lot of hot air when there is a wind blowing but on a still day does little. The ventilated deck approach (like your adding a layer of insulation below the tin roof to form an air chanel) is solar powered by the chimney effect of the rising convection currents and needs no wind to work.

The ridge vent will work well in concert with the convective chanel with no wind required but if there is wind that is at least partly blowing across the ridge rather than along it, then the ridge vent really shifts into overdrive and sucks out prodigious quantities of ait. I like to minimize the need for fans unless there is no other practical way. My new house, including the shop/garage, has continuous ridge vents and ventllated eave soffits. There is an octagonal gable end vent above the garage doors but it is purely decorative and the wall isn't cut out.

[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]

[roypat2126]

Hey Pat,
I had to call on some "Son power" this weekend, as I had a touch of food poisoning....and although I didn't do much building, it kept me off the roof.

To me, any intential "hole" in a roof is a leak ready to drip so I've not really considered installing a leak, I mean a ridge vent, although all my ref. books say how it is superior to gable vents. wanted to use standing seam but the price ran me back to screw-down galvalum panels.
However, re-considering the dynamics for thermal cooling I agree the ridge vent has greater performance. And if I can incorporate your "invention" to channel the air flow under the roof deck, I think it will provide the thermal cooling the building actually requires. So, I'll follow your lead and add a ridge vent to my roofing pkg. But I'm still a bit leary about the thing leaking.
Is there a particular configuration ("S" channel, etc) that stops water, but lets air? I know they have some sort of screen to keep wasps and bugs at bay but water is a creapy critter that gets into minute cracks, and a ridge vent seems to give away 1" wide or more opening, and even with a "filter" to catch the water, it hinders low volume air flow.(Perhaps not to the extent I imagine)
I've been at Vance AFB, OK with fairly straight horizontal rains at times and might you also experiance the same at your place?
My other major concern is why my porch rafters come out 1/8 to 3/8" too short when I cut um to the exact length!!!
Have a blessed country day there, Pat!
roy

[Pat]

Roy, Sorry to hear of your discomfort. I have never observed any water penetration from snow or rain and we sometimes get a bit of wind with each. My ridge vents are way wider than an inch closer to 2 or a tad more. If you are really anal about it there are ridge vent products that have articulated flaps that are blown closed by wind while the "other" side of the ridge vent remains open in the low pressure area to "draw" air out. We left a good gap at the ridge so the top of the "chimney" of the ventilated nail deck did not keep air from also being drawn out of the cathedral ceiling area of the garrage.

The nail deck has its chimney effect even when no wind is blowing but if there is a wind than the venturi effect at the ridge vent draws air from both the volume of the garage as well as adding a vacuum assist to the chimney effect. I have a 21 ft wide by 48 ft long shed attached to the side of the garage/shop. It connects at the 12 ft level. Under the shed roof where the eaves would be if there were eaves we cut slots in the OSB of the wall to admit air into the "chimneys." On the other side there is a continuous vented soffit at the 12 ft wall height and it is vented into the bottom of the chimneys on that side.

Even in a no wind situation the volume of the garage is getting air changes when the chimneys are drawing. I have a door with a half glass with screen in the wall between the shed and the garage. I have the glass open to allow air through the screen. Quite a draft goes through there when the roof is heated which shows how well the venturi principle is working. I intend to cut a larger (maybe 2x4 ft) hole in the wall between the shed and garage to promote more circulation through the garage. I'll put a "security" type louver in teh hole. In the worst weather I don't expect to get water through the louvers as they are under 21 ft of roof to the nearest rain entry point.

As regards the boards that are only 1/8 to 3/8 too short... just carefully cut them off again a few times (just a litle at a time untill you get it right. [img]/forums/images/icons/smile.gif[/img]

Egon can explain the concept to you if you need more detail.

[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]

[roypat2126]

Yeah Pat,
I could glean quite a lot from Egon's woodworking experiance. [img]/forums/images/icons/smirk.gif[/img] But, I figured out the problem with my rafters....It was my miter saw cuttinum too short!! Actually, I'm using metal ties and when I attach them to the bander board (ledger brd) I've not been compensating enough for them.

When nailed flat they are about 3/32 tck but when their middle is nailed to bander brd and wings wrapped around end of 2x6, they tend to hold the end out just a bit more than expected. But I' m now shaving a little off the top end of rafter which results in a more perfect fit of birds mouth to ridge cut.

With gambrel roof on my barn the sides are just over 12ft, I have a 10x51 porch roof growing out the west side of it. [img]/forums/images/icons/smile.gif[/img]
I used 9ft 6x6 posts and bolted on 2x8 header (Boxed) and now installing the 2x6x12ft rafters 24ft OC. It'll have a good "chimney" space at the wall/porch roof junction and for short term I'll put up screen material to keep out critters, and later on, put in the double rafter, ridged foam and stuff.

Even now, when I'm attaching the porch rafters to the side wall, I can feel a really good breeze flowing out spaces between the rafters across the loft floor.

Continuing on underside of porch roof deck and under barn roof deck, I'll install foil-backed ridged foam to inside of the low roof rafters forming chimney up over the 8ft knee wall (storage area) into the attic space above the loft room. As you point out, Pat, the thermal efficiency of heated air moving through, coupled with venturi effect drawing on these chimneys per ridge vent should create excellent air exchange/hr.

Later on when we screen in the porch (wife wants it), I'd like to be able to "winterize" it. Also might could vent the wood shop air to these chimneys as long as I don't pull in small dust particles which would eventually build up and cause fire hazard.

Wonder if the thermal draft in these chimneys might be ample to drive a wind turbine generator? [img]/forums/images/icons/cool.gif[/img]

Have a blessed day, Pat.

[Pat]

RoyPat, Another consideration as regards the foil backed rigid foam besides installing it with the foil towards the roof is that it accumulates dust and over time you can lose considerable performance. If you get enough wind maybe it will self clean or every couple years you can spray some kittens with "End Dust" and turn them loose up there.

As regards the wind driven turbine(s)... Yup, you could probably build some that would work within your parameters but the useful output might be a bit lower than you might hope for. You might be able to charge a battery enough to light up a some low power LED night lights or something like that. Maybe you could settle for a wind chime in the venturi or a bell with its clapper attached to a "sail" so above a threshold speed it would ring. That would announce when the system was working.

I agree about preventing unfiltered air from a woodworking operation getting sucked up into the "venturi." Except for that, I'd think you could harness the available moving air column to suck the hot air off the ceiling level of your shop. Just install some grills in the ceiling and use ducts to tap into the cavities with the air currents. Think Bernoulli!

[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]

[roypat2126]

Oooooooooh, man, now let's see.....The Bernoulli principle...doesn't that mean you can tell how fast ye ol' "Bern" will travel if "oulli" the sluice gate were in the open position, the flow is steady and the angle is straight? I really didn't have a clue, Pat, but I looked it up and learned something new! [img]/forums/images/icons/smile.gif[/img] (http://www.imnoeng.com/Flow/bernoulli.htm)

Concerning your idea of "installing some grills in the ceiling and use ducs to tap into the cavities..." I'm kinda reluctant to try that application. I'm not sure if I have the desire to cook my burgers upside down on the ceiling and I never could keep my ducs lined up so think I best just stick to installin vents through the shop ceiling into the attic space. That way if a duc...or for that matter a "end-dusted Kat" trys to go that way I'll be more likely to track um' if their viscous effects are more then the dust already in there.

All seriuosness aside, Pat, I may try something different in the wood shop. My I-joists are on 16"OC and wanting to have flush-mounted light fixtures, I'll need to use 1 or 2 bulb light fixtures (something that fits between the joists) perhaps a series of 4ft units. I may install a "U" shaped panel wedged between the joists to serve as a ceiling cover, a sound deadener, and a means by which to effect a funnel for air moving to and through ceiling vents. The vents could be attached to the air exchanger/filter to help maintain low airborne dust particles. Not sure how or if this would work, or what material to use but was just sorta thinking outload. If smooth like sheet metal it might bounce noise rather then absorb, and a textured surface might catch and hold too much particulate matter. At any rate I'm pressing in to the discharge of expanding my barn roof perimeter, one rafter at a time.. As they say "onward" and "upward"..............

Have a blessed OK country day, Pat [img]/forums/images/icons/smile.gif[/img]

[Pat]

RoyPat, Don't think me finicky but I think the plural of duc is dux!!!

My shop ceiling is 10 ft. I have lights suspended just a bit below the ceiling. I also have A/C ducts suspended below the ceiling and aspire to have dust collection ducts suspended below the ceiling. The tops of the A/C ducts are about 7 inches below the ceiling to leave room for the dust ducts.

The lights have 8 ft monopole fluoprescent tubes (small diameter new fangled size) in three rows of three in a row. During the day I rarely use them but if you turn them all on it lights the place up like an operating theater... quite intense.

[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]

[icandoanything]

Pat wrote: </font><blockquote><font class="small">In reply to:</font><hr />
If you get enough wind maybe it will self clean or every couple years you can spray some kittens with "End Dust" and turn them loose up there.


[/ QUOTE ]

ManOMan, I laughed so hard I pooted.

Dick

[roypat2126]

Hey Pat. Well I L B, M R dux!! And I learned a long time ago to watch um fly over with my mouth shut....especially geese!!

My shop ceiling is 10-9 (plus the 14" I-joist space to install light fixtures). I'll be using 8 footers (also with F8 bulbs) they seem to be more energy effecient then two 4 footers.

My goal is to end with a flush mount for anything I put in/on the ceiling, and not create dust collectors like I presently have in my garage, suspended light fixtures with no lenses so my sawdust (fine sanding dust) gets very heavy at times on the bulbs and the fixture tops. I'm not that picky to keep them dust free, but I'ld like to start the new shop with a more effective dust cleaning venture. The 14" joist space should be plenty room for lights, lites, ducts, ducs or dux (or the "Louziana" style with Doux).

A couple articles I've read say the energy saver-economy lights are not really economical, as they use more energy while producing less light. Like back in the 80's when Mfgrs' "detuned" the carburated engines to meet new EPA standards. But depending where I place saws, jointer, and other equipment and benches, I plan to use 6 rows of two fixtures in 17x26 shop.

But the barn/shop/garage is coming right along. I finished raftering the 10x51 porch and will be decking it in the next few days whenever the rain stops. It's slow going when all I have is late evenings and partial weekends, but I'll get there. If you like to play in the dirt, swing a hammer, make sawdust and sweat, come on out !!! Got plenty camper space!! [img]/forums/images/icons/smile.gif[/img]
Have a blessed OK day , Pat