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nealtw 01-22-2012 09:42 PM

On the bottom of the shed roof, you are showing a vent. Do you have soffit vents across the bottom and if you do, do you also have soffit vents at the bottom of the long vaulted roof? What Joe was talking about was a vent at top of the vaulted roof above the windows. If there is 1x4 or 2x4 cross strapping on top of the rafters, the top vent may not be required. If you add another vent the shed roof, you would need to block the air flow from that area to the main attic.

Oldmandan 01-23-2012 08:01 AM

Yes, there are soffit vents at the bottom of the shed roof. But none at the bottom of the vaulted roof. I can't see any venting at the top of the vaulted roof above the windows, but I will take a closer look once it stops raining.

I blocked the vents in the main attic yesterday, and will smoke test it again sometime this week.

nealtw 01-23-2012 11:37 AM

While you are up there have a look at the construction of the roof/ceiling over the vaulted area, If there is no venting there you might be fighting a losing battle.

notmrjohn 09-20-2012 10:51 AM

Do not remove the batting between loft and attic, you may want to add some with a reflective facing toward attic.
Block the wall (gable vent), are there intake vents at bottom under that roof?
Turbine may be pulling air thru the 2 small vents. You want air to enter low and exit high. As neal sed any exit vent will "pull air from the easiest path," use something more rain, heat resistant than cardboard. Painted plywood, foil clad insulation panel. Secure it cause vents will try to suck it off.
You could duct from lower attic thru gable vent area, but it would have to be engineered so as not to make that easiest path, leaving large area unvented.
A long weather shielded "ridge vent" at top of lower roof, with intakes (soffet vents) low would be better than turbine or powered vent, but hot air would rise against loft wall, possibly damaging siding. (Should have looked at smart vent link earlier)
But all that removes heat from that attic, not loft. Is venting space in cathedral not connected to rest of attic? And there's that misplaced vent there too. Need soffet vents below. Smartvent again?
Or joe's wall vents. ( hello, joe, whadda ya know? fancy meeting you here. I got here by US mail, poor mike ;) These folks will soon be sorry.)
But loft is still heat trap. heat from room rises, can't circulate due to half wall. Do those windows open? Of course not who would want windows that open? Vents thru wall above windows, dampered, thermostatically controlled. But will loose heat from room. Fans above wall, not ceiling fans, to push air back down or fans in loft floor registers would help circulation.

slownsteady 09-20-2012 11:45 AM

I'm surprised your condo association will let you do anything to the roof or walls beyond the paint.
If your unit is a standalone, maybe you could try something. But then again, what you do to the vents may affect your neighbors.
Years ago, I was in a loft that had a recirculation fan (don't know the real name for it) which was basically a fan fitted into a long vertical tube that stretched from the loft down to the first floor. It would not eliminate the heat from your condo, but it would move it around, cooling the loft somewhat. More efficient than your typical Hunter Douglas ceiling fan.

Wuzzat? 09-20-2012 12:05 PM

So with a loft you are working against the Stack Effect.

I've heard 5 to 60 Air Changes per Hour (ACH) with avg. 10 ACH being
recommended for this application. The conversion from room volume to CFM is not too difficult. The air intake area should be 4x the area swept out by the fan blades.

Experiment first with a box fan to see what kind of temp. reduction you can get. The fan maker can help you with what kind of CFM you can expect.

Also check to see if your outlets can support a window AC. If a 1 kw room heater or toaster doesn't pop a breaker you might be good to go on this.

Here's your cooling degree days for Anaheim.

An additional constraint could be fan noise.

notmrjohn 09-20-2012 01:31 PM

"a fan fitted into a long vertical tube" I like slow's idea, even if we don't know its name.:trophy:

All that venting and blocking of attics isn't going to help much with Wuzzat's Stack Effect, that I called a heat trap. Air flow thru cathedral could help prevent some heat transfer from up there. But attic ventilation is really more for moisture control, insulation stops heat transfer.
Tube could be disguised as pilaster or column with inlet register, outlets with dampers in loft. Sound insulated tube and fan isolating mounts would cut down on noise. Slownsteady fan even quieter.;) Carry tube up near ceiling, get some air to move out of top corner. Strong flow from tube against short wall would help overcome damming effect. And don't think it would violate any condo rules. If condo cops are even aware of it.:hide:

Wuzzat? 09-20-2012 02:39 PM

And if the downstairs is cool enough the OP could have a fan pushing air down into the downstairs through a tube. The hot air rising doesn't need a fan.

The thing with the tube is, you don't want to defeat firebreaks and somewhere I saw a tube damper that closes when it detects excessive temps. as would result from a fire. The bimetallic element acts a motor for the damper plate.

This firebreak thing is kind of what's keeping me from putting in a between-joist laundry chute from an upstairs closet floor to the downstairs laundry room ceiling.

You can do it, we can help! :p

notmrjohn 09-20-2012 07:32 PM

Laundry chute; spring loaded, fire resistant "damper", weight of clothes opens it. Damper close to opening so you can push thru stuck over alls, push flap open for lighweight Victoria's Secret dainties. Don't think there's really enough room inside walls though, you'd have to build it out some. opening high enuff so kid can't crawl through and play with matches after landing on soft clothes.

To my mind, or whatever it is I have in place of one, cold air should go up. Loft already warm, pulling air out of it means more warm air at ceiling level moves in. Cool air coming up pushes warm air out of loft. Pulling air down would mean cooler air at floor level, which warms and rises. Using tube with registers at various heights in loft, including one near ceiling, various directions, and adjustable dampers, in winter close off registers that might blow on occupant, send air against ceiling to blow out down slope under ceiling pushing warm air down wall to mix with cooler air below. Like winter time reversed ceiling fan. Reversible, multi speed fan?

GBR 09-20-2012 08:57 PM

So... what did the C.A. let you do almost 8 months ago?


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