Step 12 – Wall Sheathing

With the roof underlay on, the structure is now safe from direct rain, but there is a ton of wind here in Point Roberts thanks to the proximity to the ocean, so wind blown rain is still a threat. Installing the wall sheathing will solve that problem, at least for the short term.

Many builders apply the wall sheathing to the studs before they even stand the wall up. This would have required me to rent some heavy equipment, so I decided against it. Another good thing about installing the sheathing now as opposed to earlier in the build, is that I was able to wait until I was sure that the interior of the structure was nice and dry. If I had attached it earlier before the roof was on, rain would have soaked everything from above and then the sheathing would have blocked all the wind from drying everything out.

The wall sheathing serves several very important functions besides acting as a blocker to wind blown rain. Most importantly, it provides the necessary wall bracing to adhere to building codes.  Second, it functions as the integral part of the outer air barrier, which is crucial to achieving net-zero.  Last, it will provide nailing support for the exterior rigid insulation.

Sheathing the walls solo, like the floor and roof sheathing, required a few creative bits of ingenuity.  The 4 foot high and 8 foot long sheets weigh a little over 45 pounds, and the top row of sheathing must be installed 20 feet up in the air.  Just carrying one of these sheets is cumbersome, let alone figuring out how to hold it in place and nail it with only 2 hands.  On top of that, I had to figure out how to apply a bead of caulk around the edges of the sheets and at window openings, and keep in mind that some of this would need to be done on a ladder.  The task at hand was quite daunting, but after thinking it over for a bit I was able to come up with some techniques that worked surprisingly well!

Before the sheets could be installed I had to attach some blocking halfway up each wall, in between all the studs.  This is required for wall bracing to ensure the sheathing is fully attached to the structure.  I had several extra 2×6 studs from a minor mistake I had made when ordering the framing lumber, so I ripped them in half and then cut them to fit between the studs.  Each block was end nailed to the stud on one side, and then toe-nailed on the other side.

Marking out windows and studs before installing the sheet made nailing a lot easier

Attaching the first row of sheathing was obviously the easiest.  I snapped a chalk line halfway up the bottom plate and then sank a few 16d nails just below it so that if I rested the board on the nails, the bottom of the board would line up with the chalk line.  Next, I grabbed a sheet of plywood from my stack and drew a line every 2 feet.  This would make knowing where the studs were for nailing much easier.  Next, I grabbed my caulking gun and used Dynaflex 230 to lay a bead of caulk along the top of the bottom plate, the bottom of the blocking, and the two studs where the ends of the sheet would be.  I also caulked all the way around any window openings that would be under the sheet I was installing.  After that it was a simple matter of lifting the sheet onto the nails at an angle so the top of the sheet wouldn’t smear the caulk, then positioning it precisely, and last pushing it into the wall and nailing it down.  Each sheet was nailed every 6″ along the edges and every 12″ on the lines I had drawn.

Plenty of caulk along the edges of each board and around windows will ensure an airtight barrier

Installing the next row wasn’t a whole lot more difficult.  I sank 16d nails on each stud just over the top of the previous row of sheathing.  This will leave a small gap between the rows which will allow for expansion due to heat and moisture.  I marked lines every 2 feet to line up with the studs and caulked just as I had with the sheets in the first row.  Then I hoisted the sheet up on top of my homemade scaffolding and then used a ladder to get myself up on the scaffolding as well.  From here I could install the sheet just like the first row by angling it onto the nails, positioning, and then pushing it to the wall and nailing it down.

The third row got a little more tricky.  I installed more blocking, snapped a line marking where the top row of sheathing should go, marked lines every 2 feet on the sheet, and caulked.  Then, from the second floor inside the house, I clamped my winch to the top half of the stud that would lie in the middle of the sheet, and used a c-clamp to attach the belt to the sheet of plywood.  Then I cranked up the winch until the sheet was at the right height, positioned it from inside the house on the second floor, and reached around with my nail gun to tack it down.  Then I removed the c-clamp, went downstairs, and climbed a ladder to finish nailing down the panel.

On the gable ends, I was able to install the final row just like the third row by simply moving the winch up to the gable end truss and attaching it there.  On the other two sides I had nothing to clamp the winch too!  After trying in vain for quite some time figuring out how to do it on my own, I realized this might be one of the times I needed to call a friend over.  I drilled holes in a couple of scrap blocks and nailed them to the frieze blocks, and ran one of my nail stakes left over from the foundation through the holes.  Then I ran a rope around the nail stake so both ends dangled down at the bottom of the house.  I attached one end of the rope to a c-clamp around the plywood, and left the other end dangling.

Here you can see the bar we used to help us lift the last of the sheets into place

When my friend arrived, I caulked the area where the sheet would go and then he stood on the second story and hoisted up on the rope while I simultaneously pulled in the slack at the bottom.  Once the sheet had reached the top, I nailed a second stake into the ground and tied off the rope so we could both let go and the board would stay in place.  At that point I climbed the ladder with my nailgun and gave him instructions on which way to nudge it so it was perfectly positioned and then nailed it down.

 

It may look pretty boring now, but the interior is protected from the elements!  The exterior of the plywood sheathing will definitely still get wet, but the water won’t leak through and the inside will stay nice and dry.  I will wait until it gets a little warmer in a couple months so I can be sure that the outside of the house is completely dried out, then I will install the exterior foam, water barrier, furring strips, windows, etc.  In the meantime, it is nice and dry inside and I will be starting on the plumbing!

A huge thank you to my friend PJ for his help, both with coming up with the idea on attaching the bar to the house and for his strength helping to hoist the sheets!

 

Step 11e – Drip Edge and Underlay

Today I weathered in the roof by installing the drip edge and underlay.  Together with my fiancée, Elena, who is in charge of making the house look great, we decided on navy blue/grey aluminum shingles for the roofing material.  Aluminum is supposed to hold up well against the salty ocean air of Point Roberts and the system I ordered from the Aluminum Shingle Co. came with a lifetime warranty.  This becomes extra important for a solar net zero home like the one I’m building because if you have to replace the roof then you have to remove the entire solar system first.  The aluminum shingles are built to interlock together, which not only makes installing them a little easier, but also ensures an extremely watertight barrier.

The first step in the install was to attach the drip edge to the eaves of the roof.  For the aluminum shingle system, the drip edge came with the package because the shingles will actually lock into it (even the nails to install it were included!)  For a more typical shingle roof, the drip edge can be purchased separately.  The job of the drip edge is to ensure that water doesn’t drip down the fascia as it travels to the gutter.  The face of the drip edge extends out over the fascia so the water coming off the roof drops directly into the gutter without touching the fascia.  After watching the installation video a few times, I carried the drip edge up to the roof and set about installing it.  Some small cuts had to be made with some tin snips where the different pieces locked together but overall the process was extremely simple.

Getting the roll of underlay up to the roof was probably the most difficult part.  It weighs close to 100 pounds and wasn’t quite wide enough to ride up the rails that I had used to haul up the roof sheathing.  I decided the best way to do it was to unroll a little more than the amount I needed to complete a row, cut it off, and then roll it back up.  Then it was light enough where I could carry it up the ladder safely.  Starting at one end, I nailed it down so it almost covered the nailing flange of the drip edge and then unrolled it all the way to the other side.  After tacking it at the end and cutting the roll flush with the gable end, I nailed it down with cap style roofing nails every 8 inches or so.

Step 11d – Inspection, Bargeboard, and Gable Overhangs

I’m tantalizingly close to reaching that glorious step where rain will no longer be able to harm the OSB roof sheathing or subfloor but a few key steps remain.  Most importantly, there is currently no roof sheathing on the gable end overhangs.  As you can see in the pictures, I only installed the sheathing up to the gable end trusses instead of extending it out to the ends of the lookouts, which is where the roof will eventually end.  The reason for this is that the bottom of the gable end overhang sheathing is going to be visible from below, and the OSB I used for roof sheathing has a very cheap look to it and can tend to flake off when exposed to the elements.  Plywood looks ten times better and will hold up much better to the elements, so it’s worth making the transition from the OSB to plywood just for those gable end overhangs.  This part of the roof isn’t structural however, so it wasn’t part of the roof sheathing inspection I passed yesterday.  The plywood is only to add a nice aesthetic touch.

The other item that needs to be installed before adding the roof underlay is the bargeboard.  Made of the same primed, textured wood as the fascia, the bargeboard will attach to the fascia and run along the edge of the lookouts up to the ridge.  Once it is in place, the roof will be entirely surrounded by this finished wood.  Before nailing it on, I climbed up the roof and measured the lookouts, recording the length of the shortest lookout on each side (they varied up to 3/8″).

I grabbed what was left of the primed, textured, wood and beveled the top edge at 22.6 degrees on each side, to form the shape you see below.  I also cut each piece to the length I had recorded for the side it would be attached to.  I toenailed these pieces on to each end of the roof ridge, and then snapped a chalk line across the lookouts, holding one end of the line on the edge of the ridge pieces, and the other just grazing the end of the shortest lookout.  This gave me a visual as to which of the lookouts needed to be trimmed just a bit so they would all be even.  After cutting them down with a circular saw, I mitered one end of the bargeboard and brought it up to the roof.  I eased it over the edge and lined up the top side with the tops of the lookouts, clamping it in place.  Next, I marked the other end of the bargeboard where it crossed the center of the ridge piece and cut it along this line, then nailed it to the ends of the lookouts using galvanized nails (as these nails will be exposed to the elements).

With the bargeboard in place, I ripped a sheet of plywood in half the long way, and used my winch and rails to reel the two pieces up to the top of the roof.  I lined one end up so it was about a 1/4″ from the edge of the bargeboard and tacked it down to the lookouts.  I then ran my circular saw along the opposite edge of the plywood deep enough so it would cut through the OSB sheathing.  This trimmed off about 3/4″ of the OSB sheathing, exposing half of the gable end truss to support the plywood.  This was important so I would have something to nail the plywood into.  I cut the second piece of plywood so it lined up over the fascia the same distance as the OSB sheathing, and then thoroughly nailed the plywood to the gable end truss, lookouts, and bargeboard.

Here you can see the process in action with step 1 trimming the lookouts on the right side, step 2 placing the bargeboard on the left side, and then step 3 adding the plywood towards the center of the pic

As I’ve said before, there’s nothing quite like working on a roof when it’s a beautiful day!

Step 11c – Install Roof Sheathing

I had been waiting for today for almost a month!  It has been so frustrating to watch the second story OSB subfloor get wet day after day, but today I took a big step towards getting a roof over it as I installed the first row of roof sheathing.  With all the inclement weather, I had spent plenty of time figuring out how to get the roof sheathing installed as safely and efficiently as possible.  Carrying a 4 foot by 8 foot sheet of OSB is hard enough on the ground, so the thought of bringing it 20 feet up a ladder didn’t sit very well with me.  My solution was to buy a cheap winch online and build some “rails” so I could simply stand on the trusses and crank up the OSB like I was reeling in a fish.

It worked like a charm!  The webbing that came with the winch wasn’t long enough but I had some extra rope that worked just fine.  Before I started reeling the sheathing up to the roof I used a chalk reel to snap a line 4 feet up from the fascia.  The goal is to have the top edge of the OSB sheathing line up directly over the top of the fascia.  With that done I brought up the first panel and matched it up with my chalk line.  Just like the subfloor, the roof sheathing must be nailed to the trusses every 12″ on the inside parts of the panel and every 6″ on the edges.  I used my tape measure to ensure that each truss was on layout 2 feet center to center before nailing down the OSB. Once the sheathing is nailed down the trusses aren’t going to go anywhere so this was my last chance to make sure they were nice and straight.

Before installing the next row of panels, I installed an ‘H-Clip’ roughly halfway between each of the trusses, as shown above.  These will ensure that there is enough space left between the panels to allow them to expand and contract due to heat and moisture.

Here is a more closeup look of the clip.  Once they were installed I repeated the steps on the next layer of sheathing.  When I had reached the top layer, I measured to the top of the ridge of the roof and ripped the panel down to size so it would end at the ridge line.  I moved in six inches from the edge, and then ripped it down an additional 3 inches.  This will leave a 3″ gap on each side at the top of the roof sheathing for the ridge vent.  The ridge vent will work together with the baffles to properly aerate the attic and dry out any moisture that finds its way in.  As I will show later when I start on the shingles, the gap for the ridge vent will be covered with a material that will allow air, but not moisture, to go through it.  I am currently only halfway through the roof sheathing, but hope to get the rest of it done tomorrow.  The building inspector only comes into town on Tuesdays so if I don’t finish tomorrow I will have to wait an entire week before starting the roof.  The inspector must check up on the roof sheathing, specifically proper nailing of the roof sheathing, before I can start on the shingles.

Once the other half of the sheathing is complete, I can remove the vertical 2x4s from the gable end.

Step 11b – Lookouts and Fascia

Two other items that need to be installed before adding the sheathing are the lookouts, fascia, and subfascia.  These elements will work together to add some flair to the edge of the roof line.  The lookouts run along the gable ends of the house, and will not only give a nice look to the trim, but will also support the outer edge of the roof, which will run a couple feet beyond the walls of the house.  These overhangs help to keep rain away from the walls, and also provide some shade for the windows when the sun is high in the sky.  

The lookouts consist of 2×6 lumber cut just under 4 feet long, and are installed like cantilevers.  One end is nailed one truss inside from the gable end truss.  The gable end truss is then notched so the 2×6 sits inside of it.  The other end is left loose as you can see above, and will eventually attach to the bargeboard.  This step is easier once the roof sheathing is on.

You should be able to visualize how the cantilever works in the picture above as all of the weight placed on the outer edge of the lookout will actually create an uplifting force on the inside truss.   This force will be nicely balanced by the weight of the roof.  You can also see why the lookouts need to be installed before the roof sheathing, as half of them will be covered up with the sheathing.

The subfascia attaches to the end of the truss tails.  Not only will I be using it to line up the ends of the trusses and ensure they are nice and straight, I will also use it as a support for the fascia, which I will describe next, and to provide nailing for the soffit, which won’t be added until a few more months in the build have passed.  Like the frieze blocks, the top of the subfascia is beveled to match the slope of the roof.

Straightening the trusses out sometimes requires a significant amount of force, Imagine yourself 20 feet up in the air, leaning out over the edge of the wall, trying to hold an 8 pound nailgun with one hand and applying a ton of force with the other hand… Not a pretty thought, is it?  Clamps give me an extra pair of hands so I don’t need to put myself in those kinds of positions.  Above you can see how I used two of them – one to move the truss slightly horizontally and another to move it vertically.

A couple makeshift brackets help support the subfascia while I’m getting it ready to nail in.  The main part of it was a 20 foot long 2×6 board, which weighs in at close to 50lbs.  It isn’t something you really want to carry up a 20 foot ladder!  With the brackets, I was able to pull the board up through the trusses and then ease it over the edge of the truss tails until it was lying on the brackets.  Then I would climb up the ladder to nail it in.  Once I was finished I pulled out the nails holding the bracket to the wall and set it to the side until the next time I need it.

 

The final step before attaching the sheathing is the fascia.  The fascia is pre-primed and textured since it is one of the first pieces we are adding to the house that will still be visible when construction is completed.  As you can see, it attaches directly to the subfascia.

Just like the previous parts I described, the top of the fascia is beveled to match the slope of the roof.  The edge of the roof sheathing will sit on top of the fascia.  When the gutters are added, they will run around the fascia and partially conceal it.

 

Step 11a – Frieze Blocks and Baffles

Working on the roof definitely has its perks when it comes to sunset!  Doesn’t show up as well in the picture but I had a beautiful view of a snow covered Mt. Baker there.  So when I ordered the roof trusses, I had specified that I wanted a 15″ energy heel.  This feature ensures that the attic insulation will maintain it’s full strength all the way to the edge of the wall.  I will be using blown-in cellulose insulation in the attic and to achieve my desired strength of R-60 I will need about 16.5″ of insulation (blown cellulose has an r-value of about 3.7 per inch)  A standard truss would slope all the way down to the top plate, leaving only the width of the truss chord between the ceiling and the roof.  For a net-zero home this is unacceptable.  So before we can apply the roof sheathing, the sides of the walls need to be built up to the same level as the roof, otherwise the cellulose would just fall out after we blew it in.

 

The pieces used to build up the wall are called frieze blocks.  If you look closely, you can see how I had to add in a layer of plywood to ensure that the blocks were tall enough.  In addition, I beveled the top edge of each block so that it would match the slope of the trusses.  Any place in the house where insulation exists, it becomes very important to have an airtight seal all around it.  The beveled edge will make it much easier to air seal the frieze block to the trusses on the sides, and to the roof sheathing on top.

 

You might notice that every third frieze block is a few inches shorter than the others.  The spaces there will be used for baffles.

A baffle is used to ventilate the attic.  Even with a perfectly installed roof and airtight seals all around the insulation, moisture has a knack of finding its way into pretty much anyplace you don’t want it to be.  The most effective way to remove this unwanted moisture that could potentially lead to rot and mold is to use moving air.  The air will enter the attic through the baffle and warm slightly, causing it to rise and eventually exit through the ridge vent at the peak of the roof.  As the air completes this journey, it will pick up any moisture that exists in the attic.  As you can see below, the baffle is more than just an opening through the wall of frieze blocks.  It is actually more like an air tunnel that runs over the top of the insulation.  Again, recall that it is extremely important to ensure no moving air comes into contact with the insulation. 

If you can imagine the roof sheathing going on over the top of this baffle, it will create a 2 inch wide air tunnel through the attic between the two layers of wood.  Below you can get a good look at the frieze block from the bottom.  Several months from now, practically this entire area you see will be filled with energy saving insulation.  You can also see where I added hurricane ties to lock the trusses to the top plates of the walls.

 

 

 

 

 

 

 

Step 5a – Be Confident!

It’s been a while since my last post as I had to take some time off building to put my house up for sale and finish moving all of my belongings into a shipping container on the lot.  I also discovered that when you want to get a building permit appointment, you should apply about a month ahead!  They call it an “intake appointment” (still don’t know why) and once again the county website was very helpful in letting me know just what I needed to bring (copy of deed, septic design, proof of water availability, 2 copies of plans, etc) The website had links to download several documents to bring, but one of the links didn’t work.  I eventually decided it was probably not important.

Three weeks later the big day finally came!  I went through the checklist provided on the website one more time and double checked my plans (I ended up finding a few mistakes and had to reprint two copies of a few pages!)  I was nervous and didn’t really know what to expect but it was actually pretty simple.  The plans examiner met me at the counter and unrolled my plans.  He looked at them for about 5 minutes and then told me that I was missing one thing and needed engineering.  I was frustrated but not too surprised (I’m a beginning builder after all!)  The missing item turned out to be what I needed from the link that didn’t work that I had decided wasn’t important.  He admitted that they knew the link didn’t work and showed me where to find the documents.  He told me I needed engineering because my braced wall lines exceeded the maximum of 25′ and that my deck could only extend 6′ from the exterior wall of the house (I had extended it 12′).  I was completely caught off guard and I gave a half hearted attempt to argue that my plans followed all of the county’s building codes but I also started to second guess myself.  Perhaps I had made a mistake?  I had drawn up the plans for the wall bracing months ago and didn’t quite remember the details.  He made an appointment for me for the following week and I left, disappointed but not deterred.  As soon as I drove home I grabbed my copy of the International Residential Building Code (IRC) and double checked.  I was right!  The codes clearly dictated that my exception to the 25′ max was admissible.  Furthermore, I couldn’t find anything limiting decks to 6′ in the pertinent section (R507)

I wrote the plans examiner an email clearly stating the codes that allowed me to exceed the braced wall line spacing (for those who want to get technical, make sure you read my post on wall bracing and then read at the bottom of the post) and also asked him politely to refer me to the code that limited the deck to 6′.  Unfortunately, it was Friday, so I had to wait through the weekend to hear back.  I reluctantly called an engineer as a backup plan and he told me he would happily provide engineering for me… for just a thousand dollars…  When Monday finally came, the plans examiner emailed back and informed me that the exception I was using on the bracing could only be used on one wall, and I was using it on two.  For the deck, he referred me to code 301.2.2.2.5.  Once again frustrated and thinking I had made a mistake, I painstakingly read through the code again.  There was nothing anywhere limiting the bracing to one wall!  For the deck, the code he referred me to discussed irregular shaped houses, not decks!  My house was a perfect rectangle – one of the most regular shapes there could ever be!  I wrote him one more time asking him politely to provide the code that limited the exception to one wall and an hour later he called back with the incredible news!  He admitted he was wrong!   Sweet, sweet vindication was mine!!  For the deck, he wrote that the county had decided to apply 301.2.2.2.5 to decks as well.  This was frustrating, but only a minor setback.  I would be able to build the house without expensive engineering and I could always add to the deck later.  The engineering for just a deck would be half the price.  I would have to reprint my plans (at the price of $30) but if all goes well I should have my permit in another 4 days!  I already have a backhoe reserved for Saturday so I can start digging the foundation!
Read this next section at your own risk!  We are about to get very technical and very boring!  So for those who are interested in how I taught the plans examiner something new, I will let you know.  In review, braced wall lines are imaginary lines that are designed into the house to protect against shear forces (wind, earthquakes, etc)  The section of the IRC that discusses wall bracing (602.10-602.12) is one of the most complex of the entire code and takes up at least 15 pages.  One of the first issues covered is the spacing of these imaginary lines.  As you can see in the table above, in my seismic zone (D1), the lines can be spaced no more than 25′ from each other.  However, if you read the bottom right box, there is an exception that allows the spacing to extend up to 35′.  As I explained in my page on How to Meet Wall Bracing Requirements, these imaginary braced wall lines must contain a certain amount of braced wall panels that run parallel to the imaginary braced wall line with an offset of no more than 4′.  The exception I am using allows the spacing to exceed 25′ only if the amount of braced wall panels is increased.

For me, this was no problem.  The main obstacles to planning for a braced wall panel are large openings like windows, and garage doors.  When I designed the house, I decided to go easy on the windows so I could afford to buy really good ones.  Windows are quite inefficient when it comes to sustainability.  They let the hot sun in on hot days and let the heat dissipate through them out of the house on cold days.  These effects can be mitigated by buying windows with low U-values, low SHGC (solar heat gain coefficient), and insulated frames, but at a significant cost.  Saving Sustainably means using fewer windows, but spending the money to get really good ones and strategically locating them.

Getting back to the point, I had no problem with adding more braced wall panels to my imaginary lines.  Let’s take a look at the first table that was referenced in my exception to the 25′ maximum braced wall line spacing.

The table is quite long, but we will just focus on the section that applies (seismic zone D1).  If you look on the far right side of the table you will see the CS-WSP method.  This stands for Continuous Sheathing Wood Structural Panels.  It means that we will nail plywood (or OSB) to the exterior of the framing of the house, and wherever we locate a braced wall panel, this “sheathing” will extend all the way from the bottom of the wall to the top of the wall (with no openings for windows, doors, etc).  My exterior walls are 24′ and 32′ long and at the bottom of the table there is a footnote that says “linear interpolation shall be permitted”.  Therefore, we can find the amount of bracing necessary with some basic math. The results are….

Main Floor 24′ Walls – roughly 9’7″ of bracing

Main Floor 32′ Walls – roughly 12’4″ of bracing

2nd Floor 24′ Walls  – roughly 4’4″ of bracing

2nd Floor 32′ Walls – roughly 5’6″ of bracing

Now, let’s take a look at the second table that was referenced.

Looking at item 3, we can see that the braced wall line spacing can be increased to between 30 and 35 feet if the amount of bracing in each wall is increased by a factor of 1.4.

I recalculated the bracing, rounded up to the nearest 2′ increment, and came up with the results that I noted on my plans.

It might be hard to make out but if you look closely you can see the triangles along the exterior walls that denote the braced wall panels, and if you add them up you can verify that I have satisfied the requirements of the exception to the 25′ max.