dslreports logo
site
 
    All Forums Hot Topics Gallery
spc

spacer




how-to block ads


Search Topic:
uniqs
949
share rss forum feed

swbrains

join:2004-04-14
Land O Lakes, FL

Ceiling vent to cool covered patio

We have a one-year old home in Florida where the main house roof (hip with attic space) extends over the screened patio on the back of the house. In addition, we extended our patio further out from the back wall of the house with an insulated-panel roof and screened walls on two sides. So half of the patio (nearest the house) is under the house roof with a sheetrock ceiling and the outer half is under just the aluminum insulated panel roof.

It's on the South side of the house and therefore quite hot much of the year. We have a ceiling fan but it often feels like all it's doing is moving hot air around. I'm wondering if there is some way to add ventilation in the ceiling of either the part under the house roof or the added panel roof to help hot air trapped on the patio rise up and out. It would of course be quite easy (and less risky for rain leakage) to put vents in the sheetrock porch ceiling (portion under the house roof), but I don't know if that is a bad idea for any reason. I would think it would simply act like more soffit venting and just suck the cooler air from the patio (well, cooler than the attic air!) up into the attic which has a number of mushroom-type vents to exhaust its own hot air outside.

Would this help relieve some of the hot, stale air trapped on the patio and help to lower the air temperature on the patio at all?

Are there any negative impacts of such a change (code-related or otherwise)?

Thanks in advance for any feedback on this topic...


Grumpy
Premium
join:2001-07-28
NW CT

1 edit
I would think the ventilation part is possible. The question I have is the temperature as read in the direct sun just outside the structure (your source of drawn in air) much different than the air temp inside the patio area?

Are very fast growing and fertilized shade trees an option? I have some trees here that basically double in size each year.


nightdesigns
Gone missing, back soon
Premium
join:2002-05-31
AZ
Reviews:
·CenturyLink
reply to swbrains
Start simple, if the outside ambient temperature is decent, how about just a box fan on one side blowing air in and possibly a second blowing out on the other side.

In AZ we have swamp coolers which work well, but I don't think they'll do too well in FL Humidity.
--
This Space for Rent...

swbrains

join:2004-04-14
Land O Lakes, FL
reply to swbrains
Thanks!

During the afternoon it's probably warmer just outside the patio than under the shade of the patio roof. But we would mostly like to use the patio in the early evening. Once the sun sets, the difference in the comfort level between standing out in the yard vs on the patio is noticeable. One thing is airflow is greater in the yard, but the other is that the air on the covered patio is just plain warmer, so I'm thinking if I could give it a place to go naturally (without fans), it might help. I have a ceiling fan right now, but it's basically just moving the warm area around.

Based on our backyard layout, we do have 3 new live oaks but they will take 5+ years to get large enough to render shade on the backyard/porch. We don't want to plant any trees near the porch as we'll be adding a paved patio or deck just outside it soon for additional entertaining space.

It may simply be that we do need an active rather than passive solution, although I would like something more permanent than portable fans. I bet if I could install a whole-house fan in the porch ceiling I could pull in some serious air from outside the porch!


davidg
Good Bye My Friend
Premium,MVM
join:2002-06-15
none
maybe you just need a higher speed fan. some outdoor fans barely move any air, others will move more than is required.

Also if the fan is reversible try flipping the switch to go the other way. drawing air up and forcing it out the sides may help.
--
Lack of Preparation on YOUR Part does NOT Constitute an Emergency on Mine!


The E
Please allow me to retort
Premium
join:2002-05-26
Burnaby, BC
reply to swbrains
Any chance you could post up a few pictures of the space? That goes a heck of a long way in helping us understand how to help.


Tex
Dave's not here
Premium
join:2012-10-20
kudos:2
reply to swbrains
I agree with Grumpy See Profile regarding the ambient air temperature outside the patio and the ambient air temperature inside the patio. I'm not seeing where any kind of ventilation in the ceiling of the patio or the panel roof is going to improve the conditions. Hot air is hot air. Exhausting hot air under the patio, even using a whole house fan, will just cause that air to be replaced with more hot air from outside the patio.
--
Apple Creek Vineyard and Winery

swbrains

join:2004-04-14
Land O Lakes, FL

1 edit
Click for full size
Click for full size
I do agree with this for the daytime/afternoon hours. It's just not possible to actually "cool" the porch any more than it is other than using fans to make people feel cool by blowing air on them. But it's not really possible to cool the air under the porch any more than the ambient air temperature outside the porch, especially since we're in FL and evap coolers won't really work.

However, I'm more interested for the early evening hours after the sun sets. At that time, walking just outside the porch area feels much better. I believe it is due to both the air movement and the air may actually be a slight bit cooler outside the porch than inside, perhaps due to the "trapped" warm air on the porch. I'm sure the concrete porch floor and concrete walls are still radiating the day's absorbed heat at that point and my thought was -- at that time of early evening -- the vents in the ceiling might help passively allow some of the trapped warmer air to escape up into the attic space instead of being trapped under the porch ceiling.

I'll attach a couple of photos that show the house-roof covered area and the extended insulated-panel roof covered area. By the way, the ceiling fan in the photos is now located directly over the seating area where the light fixture is showing. The photos are from last Christmas and there have been some changes but you can still get the idea of the physical structure.

HarryH3
Premium
join:2005-02-21
kudos:3
Reviews:
·Suddenlink
Is the area above the ceiling insulated? My dad had a porch like that which had been converted to living space by enclosing the porch. The heat coming from the ceiling on hot Texas summer afternoons was insane. I convinced him to have some insulation blown in above that space and the difference was amazing. The extra hot attic was no longer radiating heat through the ceiling.


davidg
Good Bye My Friend
Premium,MVM
join:2002-06-15
none

1 recommendation

reply to swbrains
after seeing it I would say you need a couple more ceiling fans. that one is just not going to move enough air to make a difference.
--
Lack of Preparation on YOUR Part does NOT Constitute an Emergency on Mine!

swbrains

join:2004-04-14
Land O Lakes, FL
reply to HarryH3
The ceiling under the house roof is not insulated in the attic. They insulated only over the indoor areas. I could probably get some blown-in insulation up there, although it is in a hip part of the roof. I have noticed that the ceiling below the attic is slightly warmer than the underside of the white insulated panel roof during the day, so I believe you're right about the attic heat radiating down.


Tex
Dave's not here
Premium
join:2012-10-20
kudos:2
Have you thought about solar screens?


ITICharlie1
Premium
join:2003-01-22
St. Louis MO

1 edit
reply to swbrains
With that southern sun shining in those windows on that concrete floor, a lot of heat will be stored and radiate out later in the evening. If you put some window shades that can block that sun, that will help a lot. Is the door the only opening to the outside? If not a window fan lot push are in during the evenings will do the trick.
--
»www.woundedwarriorproject.org/

guppy_fish
Premium
join:2003-12-09
Lakeland, FL
kudos:3
Reviews:
·Verizon FiOS
reply to swbrains
Your getting the superheated attic air radiated in the covered area with drywall, without insulation its 160+ degree air on the drywall. Get 14" blown over that in the attic floor might help a little

But this time of year, there isn't much one can do with RH of 75 ...


nightdesigns
Gone missing, back soon
Premium
join:2002-05-31
AZ
reply to swbrains
The ceiling fan may benefit from a longer down tube. There isn't much fresh air flow above the fan and the longer tube may help (inexpensive to do)
--
This Space for Rent...


The E
Please allow me to retort
Premium
join:2002-05-26
Burnaby, BC
Reviews:
·Shaw
reply to swbrains
Thanks for the pictures, that really helps. (Great space too!)

I think an exhaust fan/vent on either side of the room, coupled with two more ceiling fans ( one at each light fixture location) would make a dramatic difference. Ideally, a couple fans a couple feet above ground level blowing in fresh, cool air would be the ticket.

Screens are awesome, but they definitely do restrict airflow.
--
"All opinions stated by me are solely my views and do not reflect the views of my employer, this site, or even myself depending on my level of sanity at the moment"

swbrains

join:2004-04-14
Land O Lakes, FL
reply to nightdesigns
I was thinking about that but the only thing that stopped me was that during installation, you have to thread the wires through the downrod and then cut them about 6" longer than the tube (so you're not tucking 2' of wire into the fixture box). I'm not sure where I'd splice them to make them longer.

swbrains

join:2004-04-14
Land O Lakes, FL
reply to The E
I've been looking this evening online trying to find outdoor-rated wall-mount fans that might facilitate this. They're not particularly easy to find, and the one or two I found were quite "industrial" looking. I'd also thought about one blowing in and one blowing out on the opposite side, to help pull cooler backyard air (at night) onto the patio.


Msradell
P.E.
Premium
join:2008-12-25
Louisville, KY
reply to swbrains
said by swbrains:

I was thinking about that but the only thing that stopped me was that during installation, you have to thread the wires through the downrod and then cut them about 6" longer than the tube (so you're not tucking 2' of wire into the fixture box). I'm not sure where I'd splice them to make them longer.

You splice them in the ceiling box with wire nuts.
--
Written using Dragon NaturallySpeaking

swbrains

join:2004-04-14
Land O Lakes, FL
The problem is that I can add additional wire to the house wires in the ceiling box, but the issue is where I make the connection to the 12" leads from the fan motor that currently reach just past the end o the of the current downrod. Adding a longer downrod means the wires coming from the fan motor won't even make it all the way through the downrod. I guess I could open the motor cover and splice new longer leads from the motor but it's not really designed for that.


Tex
Dave's not here
Premium
join:2012-10-20
kudos:2
In my opinion, you need to concentrate your efforts on keeping solar radiation from heating up the floor and other objects, especially under the extended patio roof, either by installing solar screen (as I suggested earlier) or installing shading of some kind (as suggested by ITICharlie1 See Profile ).
--
Apple Creek Vineyard and Winery

Kearnstd
Space Elf
Premium
join:2002-01-22
Mullica Hill, NJ
kudos:1
reply to swbrains
I would first try finding ways to shade that patio as much as possible, Concrete has enormous thermal mass. This is why for example the parking lot at the supermarket will feel stupidly hot even at night.
--
Filan - Aurin Spellslinger - Pago - Team Legacy

swbrains

join:2004-04-14
Land O Lakes, FL
Thanks. Unfortunately, our plans include adding a patio in the backyard directly outside the porch, so we will be somewhat limited in terms of adding trees close to the porch area. We do have one very large specimen Robellini that we recently added that does offer some shade but not over top of the roof; just to the screen area below the roofline. Hopefully the three large live oaks in the back of the yard (about 15 ft out from the porch) will grow quickly and start offering some shade in the coming years.


JimDandy

@108.61.90.x
reply to swbrains
Extend the wires using crimped but splices. Stagger the splices and tape them with electrical tape. There will be enough room within the hanger pipe for the three wires and the splices.


Cho Baka
Premium,MVM
join:2000-11-23
there
kudos:2
Reviews:
·TekSavvy DSL

1 recommendation

reply to swbrains
Add a mini-split AC at either end.

»www.homedepot.com/b/Heating-Vent···c1vZc4m1
--

swbrains

join:2004-04-14
Land O Lakes, FL
I'd go for it, but do you think it would really offer any cooling in an outdoor environment (let's assume I even insulate the attic above)?


Cho Baka
Premium,MVM
join:2000-11-23
there
kudos:2
It looked enclosed in the photo.
--

swbrains

join:2004-04-14
Land O Lakes, FL
It is enclosed on two sides and on top. The other two sides are screened (and some wood privacy slats on part of the screened side). I would be afraid it wouldn't be able to compensate for all the heat coming in and cool going out via the screened sides.

Liberty

join:2005-06-12
Tucson, AZ
Reviews:
·Cox HSI
reply to swbrains
Another vote for solar screens to reduce heating up the slab.

I am in Tucson and we get our share of solar heat gain.
I ordered roll up solar screens that allow decent view out bound during day and block a huge amount of the hot part of the sun.

Ordered from Lowes and they are made in Fl