Our house is post-and beam, so very similar, with no attic/no insulation. And we're in Alabama, where we get a lot of humidity to go with the summer sun and heat. Our skylight cluster (ten separate domes) in the center of the house is roughly 10' x 17' It's clear dual acrylic, ca. 1978. The house gets unbearably hot in the summer.

We moved in the summer of 2007 but when 2008 rolled around, I started looking at solutions. The cost of replacing the whole thing was prohibitive. Then I happened across the covers linked below. It's a fabulous solution. It basically bungees on and off. We put it on some time in May and take it off around September and store it. You do lose the brightest light, but there is still plenty of light for me.

As for the color of the roof, a lighter color will always reflect more light. You just want to make sure that whatever you paint on it doesn't harm the roof itself in any way.

Here is a link that might be useful: skylight covers

That is so funny, as I've been looking into these skylight covers, and it seemed too simple. I think my skylights could be c 1978, maybe single acrylic. Do these covers keep it much cooler without having to switch out the skylights and paint the roof? Also the companys mostly sell the brown covers, but I found one that has a light stucco color. The apt. is very white, do you think the color of the cover matters?
Do you think I should wait on buying new skylights and painting two coats of white reflective roof coating and try the skylight covers first?
here is link:http://www.lowes.com/ProductDisplay?partNumber=354718-29-5532-1-30&langId=-1&storeId=10151&productId=3372930&catalogId=10051&cmRelshp=req&rel=nofollow&cId=PDIO1

I can't speak to the variation in roof color. Ours is a light gray. But I can speak to the efficacy of the skylight covers. I know they seem really simple, and maybe a little silly, but that's the beauty. Easy on, easy off -- even with one as large as ours. Even if I'd had an unlimited budget that wold have allowed for new skylights with some sort of built-in shade system, I might have still gone for the simple cover.

Our cover can't be seen from the ground outside, so there's no need to "match" it to anything. We chose the gray-ish color, as it was the lightest available. On a clear day, you can stand under the skylight look up and see the trees. It doesn't totally obscure the view. I can't remember if we got the 80% blockage or the 90% blockage (80%, I think), and it's been fine.

As for the reflective coating, I'm sure it will help if your roof is currently dark. But you need to speak with someone to make sure the coating won't adversely affect whatever roofing system you have currently.

Oh, and for bonus points, the fabric smells just like the interior of a '63 VW. It's a little nostalgia trip twice a year when we put it on and off.

So you mean who have these covers and still no insulation on your roof? and a regular flat roof? and these covers made all the difference? Do you use AC? The roof is light, but has no insulation... my roofer says I don 't need the reflective coating, but he's not living in the sauna like apt. In any case I'm ordering the covers..... though they are pricey $150 for 1, I need 3....

My roof isn't flat, but very low-pitch. The roof itself is torch-down. My ceilings are tongue-and-groove and there is a small cavity between them and the roof decking -- maybe 6 inches. I have no insulation in there. We do use A/C. We're in Alabama -- not having A/C isn't an option like it might be in coastal CA (not sure where you are). But before the cover, the A/C had trouble keeping the large room comfortable. After the cover, not so much.

Perhaps you should buy one cover and install it and then compare the units/rooms to see if it does what you want it to do. I would think $150 would be a drop in the bucket compared to the cost to purchase and install a new skylight that vents and/or has a shading component.

These pics (with no skylight cover) will give you some idea of what I'm working with (the skylight is in the center of a great room that measures about 20' x 50'):

I have a frosted barrel skylight that runs over the top of the bathrooms. It does a much better job of controlling the heat, but still lets in light. We didn't get a cover for it. That might be something to consider if and when you do swap out the actual skylights.

I have 3 of these, and might get the covers one at a time, like you said... I should have had installed 5" insulation before capping roof. Now it's required here in California, so next roof will do, Meanwhile, the reflective paint is supposed to help, I am working with a roofer so hopefully this one knows what he is doing, and I may get the double domed skylights.... I have frosted in apt. next door and they are better but the unit gets hot too. Roof insulation is key..... I don't like ac and prefer to live without especially since we're near the coast. Thx for your help.

I had skylights in a previous house. Yes, the rooms can get mighty hot from them. We came up with a quick fix though; sheer curtains! I took some white sheer material and sewed rod pockets at both ends, inserted tension rods and hung them across the skylight. I had a fabric width and length just a little larger than the window size. The sheers blocked enough light to keep the room comfortable and control the glare. We had to open them up a little on the coldest winter nights or else the glass would ice over and later melt causing water stains. This idea looks best when there is an alcove around the skylight, but you might be able to adapt it for your needs. Another slightly tacky idea is to use frosted spray paint. Good luck.

You can also get what they call solar shades from the skylite companies or I am certain someone makes them retrofit for obsolete or generic brand skylites. They fit in where the screen would go on an operating skylite and will bock most of the heat and UV rays.

I've also seen radiant barrier paint. I've never tried it, but perhaps you can paint the ceiling with it.