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-   -   Want to raise my ceiling and have insulation questions (http://www.diychatroom.com/f9/want-raise-my-ceiling-have-insulation-questions-170590/)

rjm102478 01-30-2013 05:24 PM

Want to raise my ceiling and have insulation questions
 
Hi. I have a small ranch house (560 sq ft). The ceilings are at 7 feet with a very small attic. The middle of the attic is between 3 and 4 feet high at the most. Right now there are only 2 gable vents and a strong attic fan - 1900 cfm I believe. There are no soffit or ridge vents.

I originally wanted to completely vault the ceilings but I do not think that is possible with no soffit vents or ridge vent. And I do not want to sprayfoam and have a hot roof system.

Instead of completely vaulting the ceiling, I am thinking of just raising the ceiling rafters to the upper limit for an effective rafter tie and making a new flat ceiling on top of that. My concern is insulating. A good portion of the roof rafters will now be in the conditioned portion of the house and contain insulation and be drywalled up the new ceiling.

Here is what i want to do: I want to leave a part of the attic intact on the side with the attic fan. I would install baffles in the rafters and use batts up to the new ceiling. I would then insulate above the new ceiling with batts. This would leave a small gap between any ceiling insulation and the roof. A portion of the gable vent opposite the attic fan would also still be there.

With having a gap present for all areas of the roof and keeping the ability to run the attic fan, is this a viable option for properly insulating and causing no harm to my roof?

Thank you for any help and suggestion!!

jagans 01-30-2013 05:35 PM

2 Attachment(s)
Scissor Truss.

Gary in WA 01-30-2013 09:12 PM

Where are you located?

Gary

rjm102478 01-31-2013 08:57 AM

Pocono Mountains, PA.

Gary in WA 01-31-2013 09:37 PM

The powered fan is probably exhausting your conditioned air from the rooms along with soffit supplied air. http://www.advancedenergy.org/buildi...%20Studies.pdf You can only move the ceiling joists up 1/3 the total height of the rafters and furr down to get the code required R-value in; if Zone 5-http://publicecodes.cyberregs.com/icod/irc/2009/icod_irc_2009_11_par002.htm

Above plate/below ridge board, pp. 4: https://docs.google.com/viewer?a=v&q...XmZ9R0GxcRV0mA

Or go with a Structural Engineered ridge beam- scroll down a few; http://books.google.com/books?id=E5S...raming&f=false

R-38 is required: http://publicecodes.cyberregs.com/ic..._11_sec002.htm

A permit is required for either structural change, see your local AHJ.

Gary

jagans 02-01-2013 12:01 PM

What exactly was wrong with No. 2?

I just wanted to know before I stop posting to this forum because people ask questions, you spend your time posting good answers and they don't even comment or thank you for them, even though you have 40 years experience in the construction industry.

If you use a tied rafter, you cant go over one third the distance up the rafter legs, and you MUST bolt the rafter ties.

A scissor truss solves all your problems, gives you a vaulted ceiling, which is much nicer than a pan.

Maybe its the cost? That dosent make sense either, there is more board feet in a stick framed roof with tied rafters than trusses.

HomeSealed 02-01-2013 12:10 PM

rjm, you said that you had no soffit vents correct? So what would be your reasoning for leaving a gap(via baffles) for airflow? IMO, your best bet is to make it a hot roof and call it a day, otherwise you'll probably need to do some reconfiguration as described above.

rjm102478 02-01-2013 03:14 PM

Sorry, haven't had a chance to get on here much but thanks to all who have replied. Im still considering the options.


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