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Lucerne96 (Lucerne96)
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Username: Lucerne96

Post Number: 7
Registered: 03-2011
Posted on Saturday, March 12, 2011 - 09:06 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

The vapor barrier should be on the side of the wall facing the inside of the building. Here is a good reference

http://www.buildingscience.com/documents/digests/bsd-106-understanding-vapor-bar riers/files/bsd-106_understanding-vapor-barriers.pdf
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Pj42 (Pj42)
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Username: Pj42

Post Number: 1
Registered: 02-2011
Posted on Tuesday, February 15, 2011 - 11:50 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

I am installing vent chutes and a ridge vent above a conditioned space attic.

I would like to know if it is advisable, inadvisable or inconsequential for the slate if I use a reflective surface facing up in the bottom of these chutes.
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Wes Hunt
Posted on Sunday, October 12, 2003 - 08:45 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Six years ago my wife and I bought a 120 old victorian house here in North Central PA. We are in the slow process of restoring it. It has fading and crumbling PA black slate roof with red slate trim at the ridges. The pitch is 12/12. There are 4 gables and 4 valleys.
The ice damming along the valleys is pretty bad and in some areas has caused wood rot. I have replaced as much of the broken slate as is possible. In the valleys I have patched holes and painted them. Our goal is to nurse the roof along for a few more years while we save the money to buy the slate and metal to replace the existing roof. I have read the "The Bible" and I follow the discussions on this Web site. I understand that a big cause for ice damms is to much hot air in the attic. Therefore, I checked our attic floor and it is well insulated with fiberglass batting. What is not insulated is the 8' section of each of the upstairs bedroom ceilings that are at a 45 degree angle and parrallel to the roof. In these secctions there is no insulation. The bedroom ceiling lath board is nailled directly to the roof rafters creating a 12 inch by 2' pocket of air between each pair of roof rafters. The eaves are exposed rafter tails and a decorative beadboard deck. No real soffit to speak of. You can acces these sections from the attic and the easist way to get insulation down them would be to blow it in.

My questions are as follows: would blown in insulation work or would there be a problem of air circulation? Is there a need for a vapor barrier? I am not sure how I could get conventional fiberglass batting into the two foot rafter sections as that the opening is pretty small with the attic ceiling joists coming in and there is no practicle way to get to to the eave side to pull the batting down. I would appreciate any suggestions or comments and thank you Jenkins publishing for this discussion forum.

Wes
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Walter Musson
Posted on Monday, October 13, 2003 - 08:14 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Wes,
There is no perfect way to solve your heat loss problem.Yes,ideally you would have insulation coupled with a poly vapor barrier and vents at both eaves and ridge to exhaust warm moisture laden air.There are limits as to what you can do as you pointed out.
Some blown in insulation,preferably fiberglass,could be installed as you suggest,but a vapor barrier is not feasible nor is much in the way of ventilation.even so it would help your ice damming somewhat.
Have you considered removing some slate at the eaves to increase the metal work at these points so that even if ice does still form it can't penetrate the structure as easily.Sounds like the slate is almost gone anyway.
At that point it's a question of aesthetics by using extra metal as an ice belt.
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slateworks
Posted on Monday, October 13, 2003 - 09:23 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Hi Wes,Are the uninsulated spaces in the area of your problem? Blown in insulation would work-you could add a roof vent as needed over the newly insulated space if you are worried about ventilation-Another option is to remove the slate from the roof-cut out your roof decking(NOT THE DECORATIVE BEADBOARD)install a vapor barrier and your insulation with a foam spacer for ventilation and roof vent ect.reinstall decking-install 30# felt or ice and watershield re-install slate.Ice damming is a tough one-I have seen it cause leaks on old-new-insulated-unisulated-slate,tile and shingled roofs.If your roof is one to hold Ice and snow I believe the best way to help eliminate leakage when you install your next roof is to install Ice and watershield in your valley -18"up each side-then add another 18"to 36" to each side of th first piece-Install your valley metal 10" up each side-then install 30# felt over the ice & watershield and 6" overtop of your valley metal,(you can also install the second piece of ice & watershield a couple of inches over the edge of the new valley)We have had very good success with this method..Hope this helps, Ron
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Wes
Posted on Tuesday, October 14, 2003 - 07:04 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Thanks for the suggestions guys. I think what I will do for now is use some blown in insulation. Later when I reroof with new slate I will consider wether ripping up the decking to insulate properly is worth the effort. I like the suggestion of using a vapor barrier and foam spacer. It seems that no matter what I do on this house the best way always seems to be the most labor intensive. Such is my life. Thanks again. Wes
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Janet McNeal
Posted on Saturday, June 26, 2004 - 11:29 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

I hope this is the right place to ask this question. We have a 100 year old house with a pitch roof with slate as the roofing material. We would like to finish this attic space but need to know what the proper method is to insulate this area. All you see are the tresses and the underneath of the slate roof. I am sure this has been done before but do not know what the best procedure is to prevent damage to the slate roof. Please help me. I've looked everywhere. Thanks. Janet
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Anonymous
Posted on Sunday, June 27, 2004 - 09:31 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

You need to install foam baffles from eve to ridge. At eve you need to vent so air flows from eve to ridge through baffles. Then you need to install a ridge vent along comlete ridge (peak) of roof. You need to cut 2" down on each side of ridge(away from ridge beam) to allow air to flow from eve to ridge on roof side of baffles. Have done this lots and lots of times with success 100% of the time. DON'T INSULATE DIRECTLY TO UNDER SIDE OF ROOF NO MATTER WHAT ANYONE SAYS WITHOUT BAFFLES. Baffles allow air to flow.
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admin
Posted on Monday, June 28, 2004 - 01:08 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Yes, styrofoam baffles can be bought at any building supplier and they keep the air flowing against the sheathing boards. However, if you have a roof space (i.e. above the collar ties) you can ventilate out the gable ends rather then out the ridge, assuming there are gable ends (and not a hip roof). For one inexpensive way to ventilate slate ridges see http://www.jenkinsslate.com/install_hips_ridges.htm

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