Attic for light storage only
 

I just finished cleaning out 50 years worth of junk from my attic. The house is 1300 sq ft, built in 1939, with 2x6 joists on 16" centers. Only a small area around the stairs is floored, with 1x6s. I insulated between the joists years ago. It gets VERY hot up there in the summer even with a gable fan and eave vents, so I want to cool it and put down some more flooring for storage.

My questions are:

Flooring: 15/32 plywood OK? I will probably have to cut these to 2' x 4' or 8' to get them up the stairs by myself? OSB would be cheaper but would it be OK?

Insulation of roof between rafters (2x6) and end walls (2x4) : 3.5" roll fiberglass with vapor barrier to inside? Or no vapor barrier?

Thanks in advance.

OSB is fine for areas that stay dry.

Your OSB is fine as is your insulation selection. Although I think paper backed insulation is a little easier to handle.

No vapor barrier under roof but foil backed does add to the value.

As for flooring anything will work. Even 3/8ths ply running across a few joists will support you and a light to medium load. 1/2 OSB is good too and it doesn't really care which way you put it.

Of course you'll land your seams on the joists. No blocking required for what you need.

While it's all open still, you might want to double up some of those joists.
(every second one perhaps? idk)
Use thin strips of https://en.wikipedia.org/wiki/Laminated_veneer_lumber
That will add a lot structural integrity without too much weight.

Pine lumber is mostly water. It will twist into a pretzel when it dries out taking the rest of the house with it.

Put a higher cfm temperature-controlled gable fan in there instead? That one doesn't seem to be doing the job as is.
Or add a few roof turbines?

Curious- 2x6, 16" centers. One very important number is missing.

How far do the 2x6s span?

If you don't have it already, now is the time to add and outlet and lights....Above my garage, I used 3/4 OSB to cover an area 48X 20 ft........Lot's of storage...

what is the span? 2x6's are limited in their ability to carry weight. Even old full dimension wood

What's your largest unsupported span? Up to about 10' you should be good to go with just decking the 2x6's. Above that and you should be selective on where you store things.

I just finished removing some stuff from my attic when my roof was re-roofed with aluminum. Mostly holiday decorations that are only used a small fraction of the year.

Mine gets hot as well - a gable roof with a vent on either end. No eaves venting so air flow is only north-south. The new reflective silver metal should help vs. the old asphalt shingles.

I asked on a different thread about adding a fan on one end controlled by a thermostat but never got a response.

This is the one I was looking at:

Cool Attic CX1500 Gable Mount Power Attic Ventilator with 2.6-Amp 60-Hz Motor and 14-Inch Blade

Thoughts?

12 ft span max on the joists to load supporting inner walls.

If I use paper backed insulation between the rafters, does the paper face the inside of the attic?

Duh, I hate sounding so stupid but the internet is full of conflicting info.

Definitely adding another fan or 2 and some better lights.

I just ordered a recording thermometer with 3 sensors so I can monitor attic temps. I don't even know how hot it gets. And if I add a fan, the thermometer will help me with data acquisition.

I have a low slope roof so not a lot of room but would like to store a few things up there. The heat concerns me.

Sorry, I musta missed that one?

I like em' but not sure how effect they are since I have never tested it with any instruments. When its 120 up in there, every bit of air flow will help is my opinion. I always put those things, or power fan or vents in homes in general knowing every bit helps. I put them in my parent's home. They have high ceilings, almost 10' 1930's Spanish home. I remember, it was cold but relatively cool during the warm months. Once it got near 100, nothing would help. I stuffed a huge amount of insulation in the attic and installed two of those gable fans on a thermo switches set at medium setting. One to draw air, the other would push air through the attic with normal vents on other sides.

By doing so, I was able to reduce interior temp by about 8-10 degrees during summers. What made the huge difference was the new windows, I truly believe. At 85-90 degrees during summer, their AC doesn't come on until after 1-2pm. The house is much warmer too in the winter months. In the past 15 years, their ac has been set on auto at 79 degrees come April until October.

I forgot to mention, mount those fans on rubber or urethane of some type to dampen vibration. I have done it with and without and really notice no difference unless the house is dead quiet, I bearly notice them kicking on.

Glue and nail or screw 5/8 or 3/4 plywood sheathing will make it so much stronger. Blocking it off makes it ever stronger. Other then that, I wouldn't double up on the joist. I really don't think its necessary. Again, I don't know the span. If you really think about it, it will support you up there without any issues, so if you plywood and or block it off, that will distribute the weight evenly. What are you going to store up there, a diesel engine? Just boxes of junk that weight 25 -30 lbs max? It will hold up just fine.

Thanks for chiming in, Jeff. Always appreciate your take on all things construction/home improvement.

I feel the same way - it's gotta provide some relief.

I will be setting up a thermometer to monitor and will report back.

10-4 on the windows. Mine are not that great but will be a while until I get to those.

Thanks again! SmileWavy

Spend a few bucks more on quality Low-e glass, it makes a huge difference. Don't get those " For 25 bucks more, You can have low-e glass" BS.

I can stand under my skylights at 1pm with 100 degrees outside temp. I will feel little heat, very little unless I stick my nose up against the glass. Even then, it isn't hot at all.

+1

You can also run a few 2x6's from joist up to rafter to add some weight bearing support. Make sure you drill thru joist and rafter to attach a carriage bolt, don't use lag screws.

Get a structural steel contractor to install wide flange beams with 1/2" steel plate. Add 8" diameter steel columns on 6' centers through the ceiling and floor to the bed rock. That should do it.

I'll have to wait for my tax rebate check to get here to cover that, unless you will spot me. I'm good for it, I promise.

Cooling an attic.........
 

The best thing you can do is have a continuous ridge vent installed along the peak of the roof. That will give you continuous hot air venting without having to install a fan or other type of powered vent. I had that done several years ago when I had my home re-roofed and it made a lot of positive difference!

Too late! Re-roofed 5 years ago. I doubt that I'll live long enough to need another.

Thanks, though.

We switched to a ridge vent on the roof after a hail storm destroyed the original roof. The builder had put in electric powered fan motors that had a temp sensor and they kicked on at some preset temp. After several years they start to make a lot of noise, and I had to replace one. I can tell you standing on a ladder in the attic to get up 15 feet to the motor, and take it out from underneath is something I would never do again.

The ridge vents are nice.

Ridge vent...........
 

A roofer could install a new ridge vent over your existing roof since shingles overlap from bottom to top. Probably would not be too expensive. I would at least call a roofer and ask!

Good to know. Thanks!

Thanks! Low E is the schizzle, for sure. I already replaced one with Low E and will do the others too at some point.

My understanding is the ridge vent is not as effective without soffit venting to help the flow.

I'm not saying a ridge vent isn't a good idea, but that the whole venting process usually includes more than one aspect for it to all come together.

When we re-roofed my house in metal earlier this year, we decided against a ridge vent, and just stay with the two existing gable vents and passive venting. They are oriented north-south so that should work the best for our prevailing wind directions here.

Earlier in the thread I mentioned the prospect of adding a thermostatically controlled fan to push hot air out one end and that is something I'm probably going to try. I have a recording thermometer on order to help me with stats.

Bingo! That last piece of the missing puzzle.

The ridge vent vents the air inside the attic space.
-Heat travels to the ridge.
-Outside winds help pull air out.

It cools the underside of the roof (rafters/sheeting/shingles) with airflow.

But it doesn't work without an incoming source of air, lower down, where it is cooler.

That's exactly what I tell my clients and never forget to double up on the cost of the engineering. how the hell do you think I pay for my "Porch" parts?

It works, just not as effective. Hot air rises and if there's an exit, it will go out through there as long as there another source or opening it will work. Its too slow for me and by the time it makes any difference, the whole damn house it hotter then heck. I like moving air mechanically, it just a bigger helper doing the work

Pop those fans right on the inside of the gable vents and have one pull and one push air through. You can even install a shield to push deflect the air up near the ridge to help recirculate the hottest part of the attic. Those fan will help a lot. During those 95 degree days here in socal, they are running 8-9 hours daily.

So you're saying use 2 fans, huh? Interesting. I'm on board but am going to take it one step at a time.....and analyze. ;)

To that point....I received my recording thermometer with three sensors and have two sensors outside and one in the attic.

Guess which one is in the attic? :p

http://forums.pelicanparts.com/uploa...1587159018.JPG

Wait another month, it aint gonna to be 78, more like 98:eek:

75deg in the attic space in Florida?

What kinda shingles you got?
Mexican clay tiles coated with titanium white?

BTW...if you are feeling a bit too hot....it is SNOWING in Michigan today.

Yup. And we have been breaking records for heat on top of the usual Florida "God-awful" heat we get. I know it's also happening elsewhere so don't mean to sound like we're special or anything....lol....

I have a 2 car garage with a flat roof and peel and stick that we replaced the tar and gravel with about 10 years ago. I just bought some Black Jack silicon roof paint to apply to that to get the reflective thing going there. It is not climate controlled (yet) so hoping this will help for that structure.


New metal roof which replaced shingles.

Looking at the image I uploaded, the top reading is inside my home where the base unit sits. #1 is outside front patio, #2 is attic, and #3 is outside back patio. Note the 10 degree higher temp delta. And that's under cloudy skies! :eek:


Yeah that doesn't help, thanks. :D Not too bad here yet - but it's coming.....

Every time I see the title of this thread I wonder why anyone want to try to store light. Just flip the switch and take the light with you.