The Log house Project begins........

[dave1949]

Hey Rick, I know we have been discussing your roof like last weeks laundry, but I have enjoyed your posts and watching your home take shape. I don't believe I've ever met your equal for re-purposing materials in an artful way. You have a lot to be proud of in your work.

 

[MotorSeven]

Yep, Pacer has done the forensic examination spot on. It is 3" of unfaced styrofoam. Y'all are talking about horziontal purlins like that's odd...I have never seen vertical purlins, so as far as I know all purlins are horizontal...right??

Eddie, you bring up a really good point of creating a second condensation point with another vapor barrier. I could solid foam it between the purlins, but I will still have that rib and it's airspace to contend with. Short of pumping in foam to fill all the voids, I have no other clue how to stop this issue in it's tracks. I can't be the only guy in North America with an insulated tin roof...this has to be a common problem. I really don't see how on earth foam could be pumped into those 5 spaces between the purlins with any consistent result. I considered attaching the roof directly to the foam, but with 3" of foam depth this just would not work without kissing a dent in the tin at every screw.

All this leans me towards a more aggressive vented ridge cap and yes Brin I can buid a solar powered exhaust fan to fit inside of it(thinking one at each end of the house).

Rock Knocker, yes a ventless 28K btu propane fireplace along with a 100K btu wood stove(basement).

Y'all are great...kicking around all these ideas...it gives me much to ponder.

Thanks Dave...scrounging is an art...er...ah....maybe a sickness:laughing:

 

[Rock knocker]

Rock Knocker, yes a ventless 28K btu propane fireplace

That's the problem right there

 

[MotorSeven]

That's the problem right there

Yes I have had my suspicions from the get go on this. Later this week the temps are going to drop to similar conditions when the drip appeared and we were running the ventless. I won't run the ventless and see what happens the next morning.

 

[Rock knocker]

If I remembered back to my college days, I could tell you how many gallons per hour at 100% efficiency how much water a 28 K BTU NG appliance makes. It is considerable, and propane would create even more for the same BTU

 

[Rock knocker]

I joined this thread late, but I just want to add that you have a beautiful building

 

[pacerron]

Yep, Pacer has done the forensic examination spot on. It is 3" of unfaced styrofoam. Y'all are talking about horziontal purlins like that's odd...I have never seen vertical purlins, so as far as I know all purlins are horizontal...right??

Eddie, you bring up a really good point of creating a second condensation point with another vapor barrier. I could solid foam it between the purlins, but I will still have that rib and it's airspace to contend with. Short of pumping in foam to fill all the voids, I have no other clue how to stop this issue in it's tracks. I can't be the only guy in North America with an insulated tin roof...this has to be a common problem. I really don't see how on earth foam could be pumped into those 5 spaces between the purlins with any consistent result. I considered attaching the roof directly to the foam, but with 3" of foam depth this just would not work without kissing a dent in the tin at every screw.

All this leans me towards a more aggressive vented ridge cap and yes Brin I can buid a solar powered exhaust fan to fit inside of it(thinking one at each end of the house).

Rock Knocker, yes a ventless 28K btu propane fireplace along with a 100K btu wood stove(basement).

Y'all are great...kicking around all these ideas...it gives me much to ponder.

Thanks Dave...scrounging is an art...er...ah....maybe a sickness:laughing:

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Rick,
Perhaps a modification of this "false roof" sketch would work for you.
Roof sheathing plywood was $26 a sheet here before the big storm on the coast. Probably more now.
building a log cabin with logs for trusses and roof framing

This problem is more frustrating than an old Hesston baler:2cents:
Ron

 

[Robert_in_NY]

If you do end up removing the roofing one option for more air flow would be to drill multiple holes in each purling. It would allow more air flow with minimal work. Remove two sheets of metal first thing, drill lots of holes set your outside sheet back down then as you pull the third sheet you can slide it into place where the second sheet was. This way you dont need to lower each sheet and worry about damage. Also would keep more of your roof protected in case of rain.

I would think lots of ¾" holes would be helpful with air flow. This is why I'm not a huge fan of metal roofing. I don't mind it for siding but dislike it on roofs. Best of luck with finding the problem and solution.

 

[PAGUY]

Am I right in thinking that this problem could have been avoided by having a shingled roof instead?

 

[MotorSeven]

Ron that sketch shows a 2" air space between the upper sheathing and foam.....me thinks that is a real good place to have moisture condensate on the bottom of the sheathing......no?

Robert, I can't drill holes in the purlins, they are only 1" thick. I really wonder how much airflow that raised rib carries since there is plenty of them. I also don't think I am getting the full potential out of those ribs and airflow with my current ridge cap.

PA....shingles???? {Gasp}...NEVER:laughing: