Roofs need to breathe. One normal way an attic is ventilated is to have soffit vents so air can circulate from the vent up the roof and out a roof vent. If you spray foamed the ceilings to your house and the roof trusses and you didn't allow for this venting, you will have a very rotten roof! Take a look at this "crash course" webpage for good explanations and pictures. And, then hopefully you can figure out how to remedy your situation...

Here is a link that might be useful: Building sciences roof ventilation

The OP attempted an unvented roof. Another perfectly acceptable way to treat the attic space.

i have a low pitched roof and getting to eaves [to spray foam] would be painful

What I think has happened is that he's ended up with a vented roof with inadequate ventilation. And likely a very poor ceiling to attic interface, i.e., it leaks moisture-laden air.

This post was edited by worthy on Fri, May 3, 13 at 23:28

What density foam did you use? Or more simply put, was it open or closed cell foam?

And what is the final thickness of the foam that you sprayed?

This post was edited by mongoct on Sat, May 4, 13 at 15:42

Thanks for the responses. Yes Kirkhall, i am more than familiar with a traditional vented attic, but was constructing an unvented attic, as noted by "worthy". I used 5-6" of open cell foam, and as i stated in original post, i am not confident in achieving even coverage or not having voids. This may explain the high heat but the high (88%) humidity is harder to figure out as this reading was taken when outside air and living space air had RH of 35-40%!? Assuming correct ( i know ;)) installation is achieved, i think the science and principle of unvented attics is sound, especially if HVAC systems ( like my own situation ) are in the attic. Theory being that heating and cooling costs are reduced due to a more even temp. in attic year round. I also believe that the traditional method of venting attics is flawed from an energy use angle. Vented attics are basically big chimneys sucking conditioned air from living spaces through ceiling penetrations. And even if they are sealed correctly, fiberglass is not an air barrier, allowing cold air in winter to sink to sheetrock level.
I realize that my foam job is a C+ at best, but just wondered if anyone had any insight to the high humidity levels?
I did reinstall Roof fan and will install 2 Gable vents with the intention of blocking all 3 in the fall with rigid insulation to hopefully give back some of the benefit of the foam job for the winter.
And yes, i know closed cell is a better insulator than open cell, but i read about problems with closed cell masking roof leaks, and had the open cell anyway.

I did reinstall Roof fan and will install 2 Gable vents with the intention of blocking all 3 in the fall with rigid insulation to hopefully give back some of the benefit of the foam job for the winter.

Running a roof fan is totally incompatible with an unvented, conditioned attic. In fact, it's totally incompatible with a vented attic as well!

As Dr. Lsitburek of Building Science Corp. notes in the linked article below on vented attics:

"Attics should be ventilated with air from the outside, not the inside. ThatâÂÂs why I hate these whirligig turbine vents-- because they depressurize the attic, and if your attic ceiling isnâÂÂt perfectly airtight, you suck air conditioned air or heated air out of the house." (emphasis added)

Gable vents are part of a vented, unconditioned attic; they won't help the functioning of a conditioned attic.

As Lstiburek repeatedly writes, both vented and unvented attics can work well. But you have to decide which one you're building and stick with it. There is no such thing as a convertible attic, which is what you're trying to do with a setup that doesn't function properly as either.

Here is a link that might be useful: Lstiburek's Rules for Venting

Worthy, it was his statement that he has the venting (end gables, etc) that led me to believe it was supposed to be, originally, a vented attic. Without completely getting rid of all venting, it will cause problems, as you noted (and was my poor attempt at pointing out with the first article).

You mention your HVAC is up there too. Any idea if that is contributing to your humidity?

I hope you can figure it out!

sprayed new walls and 2x10 rafters and also existing roof ( 2x4 trusses).

An unvented attic will put the air barrier and insulation at or above the roof. A vented attic puts it at the ceiling. The OP insulated for both types, planning now, it seems, to change it over seasonally.

Here is a link that might be useful: Creating a Conditioned Attic

You have to first understand the way an unvented attic works before you attempt to create one. You can't do half of one and half of the other. You need to decide which kind you want, and then start removing the offending insulation to go with the appropriate kind.

Just to clarify, i originally had a raised ranch with a traditional vented attic ( soffit and ridge vents ). I added 2 perpendicular wings creating a U shaped house with connecting attic space. The ENTIRE house had new unvented fascia/ soffits installed and a new roof with NO ridge vent. The whole attic was then sprayed. It was never intended to be a seasonal or convertible attic, but was performing poorly as an unvented space, hence the need to address it. Others have suggested increasing the foam thickness, but honestly, to spend thousands more in the HOPE that this is the solution does not appeal to me. As i said, i have activated the roof fan and with the NEW gable vents have dramatically improved the conditions in the attic ( now 75DEG 50%RH ). Why, exactly, is it a bad idea to vent attic during times of high heat/ humidity and close up tight for low humidity/cold air in winter? The Attic WAS staying moderately warm during past winter. If attic humidity is monitored, i don't see the problem?

It was never intended to be a seasonal or convertible attic,

But that's exactly the way you're using it. And if you're happy, who's to argue?

The Attic WAS staying moderately warm during past winter.

Which of course demonstrates the extent of air leaks from below the ceilings to the attic space above. The big penalty you are paying is in added cooling costs in the summer as that rooftop whirlygig sucks conditioned air through the ceiling and attic HVAC into the attic and out.

And since you've evidently not followed IRC Code 806.3 --which calls for a continuous venting space between the roof insulation and the underside of the roof deck to the soffits--you're setting your roof up for further damage. See link below from Dr. Lstiburek.

Your climate will affect what damage you may expect.

Here is a link that might be useful: Crash Course in Roof Venting

This post was edited by worthy on Mon, May 6, 13 at 21:00

A couple fo things:

Open cell foam. Note the word "open". It will absorb moisture vapor and hold hold that vapor. It can eventually saturate and hold liquid moisture, just like a saturated sponge.

Open-cell foam is indeed classified as an air infiltration barrier. But it still needs a vapor barrier to prevent the open-cell structure from holding moisture.

I use both open- and closed-cell foams. But I'd never use open-cell in a roof. Never. In my opinion, and it is my opinion, closed is the better option.

If you are going to do an unvented roof, then the foam does need to be applied directly to the underside of the sheathing.

To the house a a whole...

When the thermal envelope of a house is tinkered with, you need to take a holistic approach. You sealed the lid. If you didn't already do so, you need to address the basement as well as the living spaces below the lid. For most houses, moisture is generated in the basement as moisture wicks through the slab and/or foundation. That moisture can work its way into the living spaces through stairways, doors, and utility penetrations in the first floor platform.

That moisture, plus moisture generated in the living spaces, can work its way into the attic.

In older leaky houses, or houses with vented attics, the moisture can be whisked away through air movement. That same air movement gets rid of moisture vapor, but it can kill the thermal efficiency of your envelope.

You sealed the lid of your house, eliminating an escape route for that moisture vapor. Your open-cell foam may now be acting as a holding medium for that moisture. Thus the high humidity levels in your attic, as well as liquid moisture draining out of your soffits.

Address moisture sources in your basement as you can.

Seal penetrations in your first floor platform.

Address moisture generated in the living spaces; cooktops, showers, etc.

Seal penetrations in your attic floor.

After a dry spell when your open-cell foam has been able to go through a drying cycle and it's no longer holding water, get a vapor barrier on that foam. An easy way might be to use a topical coating to "paint" right on the surface of the foam. The coating can act as a vapor barrier as well as an intumescent barrier.

Thanks again for the responses, i really do appreciate the input.
Regarding the rest of the house as questioned by mongoct: My basement is finished, and am confident in the system/ materials i used: i put 1/2" foil faced foam on the slab with 2'' foam directly applied to foundation wall, all seams were taped with tyvek tape and wall foam was bedded in a bead of great stuff on slab foam before being taped. Metal framing in front of iso on walls. Sprayed foam between studs against iso. M.R.Sheet rocked. NO wood or Fiberglass used. i have same Humidity reading in Basement as living space above ( 40%).
Have 800cfm extractor above cooktop and fantech remote bath fans expelling through short straight runs to roof vents.
Having said that, high H.R. in attic is still a mystery.
I will pay closer attention to ceiling to attic penetrations ( Shouldn't have been necessary with sealed attic but apparently in my case it is ). The foam seems totally dry, and i have pulled it away from sheathing in a few spots to check, sheathing's dry too. ( I have a friend in a worse predicament, he has a steep foamed cathedral ceiling with cedar t&g on the interior. On inspection, his roof sheathing was WET inside due to condensation, presumably traveling through open cell).
I have first hand knowledge of multiple foam contractors giving quotes on spraying open cell foam directly to roof decks. This apparently contradicts mongocts advice of only using closed cell. His advice of spraying directly to roof deck also contradicts the information in the "crash course in roof venting" link posted above by worthy, suggesting baffles are used to maintain soffitt to ridge venting prior to foam application.
I have also read that paint is now NOT an acceptable Moisture Barrier on open cell foam due to the extreme porosity of the material. (Although i have sprayed other foamed attics with fire retardant paint ) .
The other houses i have sprayed are performing much better than my own. The difference being that those houses had more foam ( minimum 6" ) applied AND eaves were blocked prior to spraying with fiberglass stuffed poly bags. I guess i just need to address eaves and add more foam.

I guess i just need to address eaves and add more foam.

that is part of it.
the rest is that you need to close up any fan opeings
in roof and or gable ends. gable ends should also
be foamsprayed.

granted its a pita to seal low pitch roofs, but the
foam seal has to be complete from roof to eaves
to attic floor.
I test alot of foam attic jobs with a blower door..
you can bet this is the biggest leak.

I do have to say, I've never ever seen attic fan or
open gables in foam attics. those are always
closed off and foamed over.

where are you located?

best of luck.

I have first hand knowledge of multiple foam contractors giving quotes on spraying open cell foam directly to roof decks. This apparently contradicts mongocts advice of only using closed cell.

For clarification, my preference is for only closed cell in a roof structure. That's why I wrote in my original post that it's my opinion. For me, open cell has nothing but drawbacks in a roof structure when compared to closed cell.

"His advice of spraying directly to roof deck also contradicts the information in the "crash course in roof venting" link posted above by worthy, suggesting baffles are used to maintain soffitt to ridge venting prior to foam application.

It doesn't contradict at all. What I wrote was "If you are going to do an unvented roof, then the foam does need to be applied directly to the underside of the sheathing. "

UNvented.

If you want to vent your roof, then vent your roof. Use baffles. Whatever.

If you want to use open-cell, you need to protect is where required with a vapor barrier.

Flat roof no venting. Wanted to remove sheathing and spray 1” of closed foam onto the roof side of the living space creating an air seal an stopping my heat from escaping out the roof. Does this sound like a good solution?

Thanks, will do.