Thursday, March 22, 2007

restoring a house that's not finished yet...

This first picture is a sad one... we're ripping tongue and groove ceilings off of the sunroom. Lesson learned - 90lb roll roofing makes lousy temporary roofing. Water seeped through the holes caused by the roofing nails (someone told me they self seal - don't believe everything you hear!) and more water seeped beneath the roofing where it met the walls. A little water probably wouldn't have hurt these ceilings, but there was no way for the water to dry out, so it warped the boards badly. None of this is late breaking news - the ceilings in this room have been ruined since last fall, but I had resolved not to fix them until I had _everything_ needed to put the permanent roof over it. (Trying to exhibit some "learned behavior.")

Finally the day came...I had everything required to cover the sun room roof with standing seam metal, two able bodied helpers, and there were several sunny days in the forecast. The demolition went quickly - like pulling off a band-aid - it's best not to drag these things out! We were able to salvage a lot of the (now shorter) unwarped oak boards for later use as soffit. As soon as we had the t&g off, we went back over the ceiling with new poplar tongue and groove boards (the second picture). There's still a little bit of sanding and cleanup to do on the oak rafters, but so far I think the poplar looks great next to the oak.

The very next step was to add a vapor barrier. (The vapor barrier should always go on the warm side of your insulation). Then we cut holes in the new t&g for four electrical boxes. We wired the electrical boxes with aluminum sheathed 12-2 wire. Then we put down 3" of poly-iso insulation between 2x4's on 2 foot centers. That's only about R-20, but the rest of my house has R-50 insulation in the roof, so I don't think it'll be too much of a heat loss over this small room. I had to keep the insulation minimal, or my roof would be too thick and start interfering with the windows above the roof. (see picture at left).

Because this room had timber rafters, we ran the 2x4's crossways... like purlins. The timber rafter tails form a generous summer-sun blocking overhang at the eave of this room. To achieve sufficient overhang at the rake edges of the roof, we ran the 2x4's beyond the side walls of the sunroom. You could attach standing seam directly to the 2x4 purlins (like I did elsewhere on the roof), but I decided to run plywood on top of these 2x4's . I anticipate walking out on this roof and attaching various solar experiments to the standing seam roof, so I wanted to make sure there was a solid base beneath the roofing.

I'll have more pictures of this roof and sunroom to show later. Rest assured though, that by the end of the second (long) day, we had the roof permanently dried in with standing seam metal! It took two more days to finish the metal trim, fascia, and soffit on the edges of this small (20.5' x 13.5') roof.

*** added two more pics of the sunroom (3/24/07) ***


Blogger neuwave said...

Thomas, this kind of roof is exactly what I have in mind for my cabin, although I was going to use pine t&g. Your poplar t&g looks fantastic there next to the rafters, though!

My big internal debate is about using plywood or just attaching the standing seam metal roof to the 2x4's roof frame underneath. On the one hand, leaving off the plywood would allow the roof (insulation cavities) to breath better, but using the plywood would seem to be a bit more solid and weather-proof.

Did you put felt/tar paper on top of the plywood, immediately underneath the metal roof? If one did use plywood, would that be a reasonable thing to do? I've heard that metal roofs can develop quite a bit of condensation underneath, and that a layer of tar paper can help protect whatever is below.

I'm just afraid of sealing up the insulation cavities (with plywood and felt) so tight that any moisture that does manage to infiltrate will never dry out.

Any help (and additional photos) that you could provide would be useful to me!

March 23, 2007 at 3:38 PM  
Anonymous Anonymous said...


I did cover the 5/8" plywood with roofing felt before putting down the metal. The best roof would have no plywood in it. It would breath better and all that. That's the way I did my 12:12 pitch standing seam metal roof that holds the solar panels (as well as the roof that I slated). This roof was 4:12 and easily accessed through my loft windows - so I wanted to make sure the standing seam would not bend or crease when I walked out on it. That's the only reason I put plywood under it. One might argue that plywood helps stiffen the roof plane, but I doubt it helps much when it's 4 inches above the timbers that form the actual roof frame.

I took antoher picture today that I'll add if I can get !@#$!@# blogger to work. ;)

March 23, 2007 at 11:30 PM  
Anonymous Anonymous said...

Great Blogging just what I needed a post and beam fellow builder!


October 16, 2007 at 4:46 PM  

Post a Comment

<< Home