All Decked Out

Well, it took a LOT longer than expected, but I am pleased to say I am all decked out.  No, I am not talking about my Christmas decorations, or a new wardrobe.  I have finally finished decking all of the roofs of the house.

Originally I thought I would have them done in September, but was delayed in both framing the walls and receiving the truss package until late September. First trusses were not laid out till September 26.  I then thought I would be done by end of October, but the low pitch roof design using cross purlins and spacer blocks took WAY too long.  This was made much more difficult by the extent that the trusses were bowed and the engineering requirement that they be within 1/2″ of a string line.  The problem with the bowing is that it was not consistent across the truss. It would be much more pronounced at joints in the truss, meaning I could not just align at the centre point and call it a day.  I basically had to continually align as I attached the cross purlins.

Example of bowing of trusses. Was much worse when banding was removed.

While I remember, here is a tip to keep your truss pack from collapsing on its side when you release the bands. Just clamp the pack together. I would loosen the clamp, extract a truss and then re-clamp the remaining. This is important as most trusses cannot be suspended from wall to wall while lying on their side. The weight and side load will pop open the metal tie plates.

Did you know you can make a ‘spreader’ out of a clamp. All you need is two pieces of wood pushing up against the two objects you wish to spread.

So then I though I would be done early December, but both my body and Mother Nature felt differently. When I last posted on Dec 4, I thought I was done with the cold, but it then moved back into my chest and dropped me onto my butt again for several days.  Then the snow came and made me a prisoner in my own house.  It is very hard to finish framing a roof and start decking when it is covered by a tarp that is smothered with hundreds of pounds of snow and ice.  I ended up with ice dams (3″-4″ thick) and pools of water behind.  I had some pretty damp floors for a few days until I was able to address.

The rest of the year, the tarp has been awesome. But now it is trapping me ‘below’. There was no way to work on this roof till enough snow melted that I could push the remainder off from below.

I did not get back to actual roofing until Dec 8.  Then I lost a day because the very last truss I put up was not made right (go figure).  It took the better part of the day to get approval from the vendor to cut down the bottom chord by up to an inch.

But the biggest difficulty, was that I installed the north upper roof from below while standing on a ladder (tarp was too low to deck to stand above, and I was not thrilled with working on top of steeper slope.  I would get to the point where the roof was about chest high while on ladder and then screw in all of the cross purlins. But this required raising both arms above shoulder height and my broken shoulder really did not like that.

While I was installing the roof trusses and gables, I was always thinking about the continuity of the air barrier.  My air barrier will be generally provided by the self adhered sheathing membrane adhered to the outside of the wall sheathing.  This is a very easy air barrier to detail (will talk about this best practice more down the road when installing the main membrane).  At the top of the structure, my air barrier transitions to the inside and will generally be met by plywood I will attach to the bottom of the roof trusses as part of my ceiling assembly.  This leaves three areas I need to address during the roof framing stages, if I am to be assured of a continuous air tight barrier.

  1. Where ever a truss is attached to an exterior wall, you need to first apply the membrane before anchoring the truss hangers.
  2. You need to transfer the barrier from the exterior to the interior at top of non-gable walls
  3. For gable walls, you need ability to transfer from exterior to interior at proposed ceiling heights (not top of truss).

My Air Barrier (also acting as my water shedding layer) was applied to the exterior wall sheathing (this is the interface between the south roof and clerestory wall) before tying in my truss package. I will then seal the plywood, that will be installed to bottom side of trusses, to the grey membrane providing for a continuous protection.

For the top of structure non-gable walls, it is important to realize that the air barrier is a system, not any single component. SO in this case, the membrane will seal the exterior of the plywood past the most upper plate, sealant will seal the plywood to the top plate, the top plate itself is an air barrier, and then the plywood attached to the bottom of the trusses will be sealed to the top plate. Plywood will itself have all seams sealed with either tape or sealant to complete the system.

Gable Wall – Step 1
Identify where ceiling plane is located on truss chords/studs and seal plywood to truss components along this line (can just see red sealant under truss studs).

Step 2 – Fill in between the truss components with tight fitting blocking that is also sealed to plywood and truss components. Blocking should be same thickness as truss components.

Step Three – with all blocking in place, seal a 2×4 to the blocking and truss components along the ceiling plane line you earlier established.

This is what it looks like when complete. The plywood will be sealed by exterior membrane. The air barrier is then transferred through the plywood to the blocking, then to the 2×4, and then will be sealed to the ceiling plywood. There is no path for the air to move from the conditioned side of this sloped assembly to the non conditioned side.

Similar gable truss installed showing relationship between diag blocking and truss bottom chord. A 2×4 on its side is more than enough attachment roof to fasten the ceiling plywood (or drywall, if you were going to forgo the plywood and try and air seal your drywall.

Quality of T&G 5/8 roof ply left a lot to be desired. Kind of hard to line up courses with this kind of a variance (note the length of the two different tongues).

All in all, I put 317 hours into laying out the trusses, securing the purlins, framing the overhangs, and decking the 4 roofs.  And I am SO glad it is over.  I will spend the last couple of days of 2016 cleaning up and then will start prepping the window and door openings in the new year.

With that, I would like to wish you all a Happy New Year and all the best for 2017.

This entry was posted in Project Journal. Bookmark the permalink.

4 Responses to All Decked Out

  1. Homayoun Arbabian says:

    Hi Sean
    I hope you have enjoyed the Christmas Holiday.
    I wish you a very happy new year ahead.

  2. Nico Straatman says:

    Hi Sean,

    we wish you all the best in 2017.
    Great to follow all the steps in your very interesting project. Nice that its all covered before the winter. Succes with the rest and finishing!!

    Nico Straatman (father of Victor)

    • Sean Wiens Sean Wiens says:

      Hi Nico,

      Great to hear from you. Thanks so much for your comments and for visiting the site. Wishing you too the best for 2017. When do you think will be your next visit? Roy and Yuri are sure enjoying the snow but I could definitely do without. Take care. Sean

Leave a Reply

Your email address will not be published.