Step 10 – Frame the Second Floor

You can see how I’ve been trying to keep the OSB flooring dry with a tarp but with the walls going up it is difficult.  Luckily, I spent some extra money on Weyerhauser EdgeGold OSB subfloor and according to their reps they are perfectly fine to get wet for a few weeks as long as they are given time to dry out.

Framing the second floor is not a whole lot different from framing the first.  Whereas on the first floor, the sill plate was pressure treated lumber, this isn’t necessary on the second.  Also, the bottom plate was bolted to the concrete foundation on the first floor, but on the second we simply nail it to the rim joists as you can see below.

Before raising the exterior walls, I toe-nailed the inside edge of the bottom plate to the floor boards.  These nails help enure the wall stays in position and doesn’t fall off the house before it gets nailed into place.

After going up and down the ladder many times cutting pieces for the walls I decided it was time to build something permanent.  The finished house will have a large spiral staircase but it would get messed up pretty quickly during building (as well as annoying) so instead I just threw together a makeshift ladder from some scrap wood.

Whereas the first floor walls were pretty simple, things got slightly more complicated on the second floor with the master bathroom as it has walled off areas for the shower, toilet, and two walk-in closets.  Several of these walls are angled, and one of the master bedroom walls is actually curved! 

Creating an angled wall is pretty simple.  You can see I have two walls meeting at a 45 degree angle on both the left and right side of the picture.  All you do is miter both top plates and bottom plates at 22.5 degrees so that when they fit together they create a 45 degree angle.  You can see how the studs meet on the inside wall and the small gap on the outer wall will be covered with a metal corner bead under the drywall.

At the center of the pic above I actually have three walls coming together in the shape of a ‘Y’.  For these I mitered the two arm walls with 45 degrees and joined them to a straight wall.  When it came time to add the top plate I had to do cut a special piece to fit with a jigsaw.

To build the circular wall, I had some 3/4 inch plywood ready.  I created a makeshift compass to get the right radius for the wall and transfer it to the plywood.  Then I drew out a second radius exactly 3.5 inches smaller than the first for the inside of the wall plate.  Sandwiching two of these pieces together, I ended up with an equivalent to a ‘curved’ 2×4.

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The one thing about a curved wall is that it uses a lot of studs!  The far side of the wall will curve right around the spiral staircase when it is installed. (I haven’t cut the opening completely yet for safety)

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step 9b – Install the Subfloor

Solving small problems is a huge part of building.  I’ve always enjoyed crossword puzzles and the like, so I shouldn’t be at all surprised that I am enjoying building the house so much.  Today’s problem was how to lift 24 sheets of OSB panels 11 feet up in the air.  (2 feet of foundation + 8 feet of wall + 1 foot of joists = 11)  You see, each panel is 4 feet wide and 8 feet long, and weighs 59 pounds, so not only are they heavy, but it is difficult just to get your arms around one.  My solution was to build a small section of scaffolding about 6 feet long and 5 feet high.  Then I would carry the OSB over to the scaffolding while holding it just like this guy is.

Turning it so the shorter side is down, I then lifted it up onto the scaffolding

Then I would climb up to the top, grab the end of it and pull it the rest of the way up.  This was easy once I had a couple of them already up there to stand on but for the first ones I had to just stand on a couple of 2×6 boards that I had laid out perpendicular across the joists.  Have I mentioned that building a house is a great way to face your fear of heights?  I lifted every single one of the 24 boards up to the top of the wall in this same manner.  The first row you attach is the most important one to be straight because all the other rows will interlock with it.  I used my chalk reel to snap a line 4 feet in from the edge to ensure that I got it just right.  Next, I applied a liberal bead of elastomeric construction adhesive to the top of the joists.

PL400 is highly recommended for subfloor gluing

I set the board down over the joists so it lined up with the one corner of the house and ensured that the other end was halfway onto a joist.  This is the reason why I lined the joists up 24″ on center.  The 8′ long panel spans 4 joists and on the outer joists it leaves enough space to share the joist with another panel.  Once the panel is perfectly lined up the code calls for it to be nailed with 8d common nails every 6″ on the edges and every 12″ in the middle areas where a joist runs under it.  The boards are marked out so you can easily find the spots where these nails should go if the joists were lined up correctly.  If you look closely you can see them…

You can also see how I left a small gap in between each board to allow for expansion due to heat and/or moisture.  Four of these 8′ long panels were enough to run down the length of the house.  For the next row, I cut a panel in half.  Staggering the seams in this way adds strength to the floor.  With the first two rows complete you can see how the staggering seams look.  Notice how I positioned the other boards so I could walk around as I worked.

When I got to the row above the blocking I used a sander to make sure that none of the blocks stuck up above the joists.  I also measured out where pipes would go through so I could easily find them later.  One of the pipe fittings stuck up above the joists so I had to cut a hole for it in the OSB.

There’s the pipe I cut out a hole for on the right side and if you look closely you can see where I marked out where the other pipe will penetrate the flooring as it heads up to the roof vent

Luckily I thought ahead a little bit and before I got to the last panel I cut out a hole for the stairway opening.  Otherwise I wouldn’t have been able to get back down!  The opening will eventually be much larger but for safety reasons I left it just big enough to allow for comfortable access.  I marked a warning on the areas that will eventually be cut out because there aren’t any joists underneath.  The OSB floorboards are strong but without a joist underneath they could easily break.

The last step was to run a circular saw all the way around the perimeter to remove any protrusions.  Because of the small gap between each board there was about a 1/4 inch left around the edges.  That and the stairway opening was the only waste I had.  This is very rare in today’s average construction job as the house plans usually call for a bunch of details and angles in the floor.  Contractors cut panels in all sorts of ways as needed and then discard what they don’t use, which can be a substantial amount.  This is one of the benefits of designing a house yourself.  I specifically designed the house with dimensions divisible by 4 feet for this very reason.

Step 9a – Install Blocking and Plumbing

Before the subfloor can be nailed onto the joists, small sections of 2×12 called “blocking” must be installed.  Together with the rim joists they ensure that the floor joists won’t roll onto their flat sides where they can easily bend.  The blocking is placed along the top of the interior bearing wall at the exact place where the two floor joist spans meet and nailed perpendicularly between them.   I kept all the plumbing of the house on interior walls so I wouldn’t take any precious space away from my insulation inside the exterior walls.  My interior bearing wall being the major wall on the first floor, this meant that it had a significant amount of plumbing running through it.  The plumbing runs through the middle of the wall, and all of the DWV pipes must be vented vertically through the roof.  These pipes want to go through the middle of the interior bearing wall and exit right into the middle of my blocking!  My solution was to simply install a double set of blocking with the pipes in the middle.

Here you see the normal blocking at the outer edges of the pic and the modified blocking in the middle. The 2×6 boards at the bottom of the pic are for me to walk on until the floorboards are installed! Note how the joists from each exterior wall meet in the middle at this point.

In addition, I had planned for some of these pipes to run horizontally in the space between the floor joists.  For example, the washing machine is on the second floor, but the space I want to put it in doesn’t have a wall below it on the first floor.  If I didn’t run the pipe horizontally I would have a pipe for the dirty clothes water running through the center of the guest bedroom!  So this horizontal run would need to make a turn through the blocking so it would run in the space between the floor joists.

The pipe on the left makes a 90 degree turn to run between the floor joists while the one on the left goes straight through the blocking and will continue through the 2nd floor walls and out through the roof

 

 

All of my planning really paid off because some of the runs of ABS pipe were required to have cleanouts.  If I hadn’t installed them before running the vertical pipe up through the blocking it would have been a pain to do later.  The one you see below will be covered with a bench seat at the dining room table.  In case of a plumbing emergency the cushion can be taken off the seat and a hinged panel will provide access to the cleanout.

For a contractor, calling the plumber out before the entire house is framed is unusual.  I’m sure they would have been able to come up with a solution without breaking their routine, but I’m also pretty sure it wouldn’t have been as neat and efficient as my solution.  For me, it was very easy to stop framing for half the day and work on some plumbing so that I could finish with the blocking.  Yet another great example of the flaws in building a house with contractors…

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Step 9 – Frame the Floor

Flooring is pretty basic, and if you’ve ever noticed how a deck is built then you have the gist of it.  Long boards called joists are laid out parallel with each other and on their sides so they won’t bend easily.  4×8 sheets of plywood or OSB are laid out over the top of the joists to create a flat, sturdy surface.  The joists are supported by some of the first floor walls.  As I mentioned before, one of my interior walls is a load bearing wall, so it will be used to transfer half the weight of the second floor of the house down to the ground .  The 2nd floor interior walls will rest on the subfloor, which will in turn rest on the floor joists.  Since the floor joists span all the way from the exterior walls to the interior bearing wall, they will need to handle a significant amount of the weight of the house, which they will then transfer to the exterior walls and the interior load bearing wall.  The pic below might help you visualize…

Notice how much weight is carried by the load-bearing wall in the middle

Proper joist sizes can easily be figured out from the IRC (International Residential Building Code) using a table in the same way you calculate header sizes.  For me, that meant looking at the part of the table that dealt with 24 inch joist spacing since that is what I’m using.  Then figure out what the greatest distance the joists will span is, which for me is just slightly over 14 feet.  Last, select a lumber option that supports a minimum span greater than this distance.  I decided to go with #2 2×12 Douglas Fir, which supports a span of up to 16’6″.  Going with an option suitable for a span larger than what I need will hopefully give me a less bouncy, less squeaky floor.

Lifting 16 foot 2×12’s 10 feet up in the air solo is a great workout.  After cutting each joist to length.  I lifted one side up in the air and rested it on the top of an exterior wall.  Next I moved a ladder near the interior bearing wall and lifted the other end of the joist up so I could rest it on the top of the ladder.  After climbing up a few rungs on the ladder, I had enough height where I could lift the joist from the top of the ladder to rest on the interior wall.  Just as with the wall framing, it was important to ensure that the crown of the lumber faced the sky.

The first joists I installed are called the rim joists.  These run on the top of the exterior walls perpendicular to the rest of the joists.  Above you can see the rim joist on the left side of the corner and the outermost floor joist on the right side.  Using rim joists ensures that there is a perimeter of joists all the way around the house even though the majority of the joists run in the same direction.  The rim joists are “toe-nailed” to the top plate, meaning that they are nailed diagonally.  Once the rim joists are up, the other joists are placed perpendicular between them and nailed to the rim joists, as well as toe-nailed to the exterior walls.

The opening for the stairway required a little bit of detail.  The code requires joists to be doubled all around the opening.  In addition, any time you are unable to rest a joist on a bearing wall, you must use steel joist hangers to carry the weight around to where it can reach a bearing wall.  The manufacturer of the hangers (in this case Simpson Strong-Tie) tells you what kind of nails you must use and what amount of weight the hanger is capable of carrying.

Step 8c – Plumb and Line

With all of the 1st floor walls complete, it was neat to be able to navigate the rooms and get an idea of the feel of the dimensions of the house.   Before moving on to the 2nd floor I needed to take some time to ensure that all of my framing so far is straight, level, square, plumb, and true.  (For those who don’t know what the last two are, plumb means perpendicular to level and true means both level and plumb at the same time)  Once the subfloor is nailed to the floor joists it will tie everything together so this was my last chance to make sure it was just right.

I started by double checking the lengths of the top and bottom plates, and the lengths of the corner studs.  Next, I used a plumb bob to ensure each of the corners was plumb.  I used long 2×4’s nailed diagonally and nail stakes in the ground to push or pull the end of each wall as needed to plumb the ends of the wall.  I knew the foundation was level, so since the wall lengths were equal and plumb, I knew the walls were square and true as well.  I repeated the process for each wall, and then checked each wall for straightness.  Now I knew the corners were right, but in the middle of the wall there might be some waving.  I nailed a 2×4 block to the top corner on each end of the wall and stretched a string tightly between them.  Using a third 2×4 block, I checked all along the wall to ensure this block fit snugly between the wall and the string.  Where necessary I used additional bracing to make the wall straight.

With the exterior walls (hopefully) perfect, it was time for the interior walls.  I used a powder actuated hammer tool to nail the bottom plates of the interior walls into place.  This uses a .22 caliber explosive to drive the nail into the hard concrete.  You insert the nail into one end, put the .22 caliber load in the middle, and then strike the other end with a hammer.  The blow ignites the load, driving the nail in.  I double checked all of the measurements for the walls to ensure they were straight and then used the powder actuated hammer tool to attach them to the concrete.

Once again, I used the plumb bob to square up the walls and attached them to the exterior walls with a splice plate.  I used additional bracing on the one long wall, but the others were so short that they should stay straight.

With this crucial step of straightening done, I was now confident enough to get going on the joists.

Step 8a – Utilize Advanced Framing Techniques

To an experienced framer, the work I have completed over the last couple of days would seem wrong.  It is quite possible they would never have seen a house framed the way that I am framing mine.  A few might even claim that I am violating building codes in not following “standard practice”.  The fact is, I am utilizing a method of framing created in the 1970s in a collaboration between the U.S. Deparment of Housing and Urban Development and the National Association of Home Builders Research Foundation.  Their goal was to reduce the amount of wood used in construction, not only to save the lumber, but more importantly, to create more space for insulation and save on energy usage.  All of these small changes work to ensure the house will be net-zero!

Image result for photo of advanced framing vs traditional

As you can see above, in traditional framing you have a single sill plate at the bottom of the wall connected to a series of studs spaced 14 1/2″ apart from each other (16″ on center) which are then connected to two top plates sandwiched together.  Additional shorter studs called “jack studs” are used to support headers above window and door openings.  Even more studs are used to anchor interior walls to the exterior.  All of the wood used are 2x4s, leaving 3 1/2″ of space between the studs for insulation.

In advanced framing, on the other hand, only a single top plate is used, studs are spaced 22 1/2″ apart (24″ O.C.), and metal “header hangers” are used instead of the jack studs.  On “gable end” walls, no headers are needed at all! (see below) “Ladder framing” is used to anchor interior walls and 2×6 lumber is used, leaving 5 1/2″ of space for insulation (obviously that’s the part of the wall that looks like a ladder in the pic)

The advanced framing system is cheaper because it uses 5% to 10% less lumber, and it is faster because it uses 30% fewer boards (although they are a bit bigger and heavier). More importantly, every single year more money is saved on energy costs because over 60% more insulation can be filled in.

This is a gable end wall, meaning it will extend all the way to the peak of the roof without slanting. Because of this, you can see I don’t have to use headers above the windows. (And yes, that is just a very light dusting of snow)

Okay, so what’s the catch?  If advanced framing was added to the building code over 40 years ago, is cheaper and faster, and reduces the energy bill every single month, then why isn’t it standard operating procedure for builders?  How could I possibly be telling you that most builders don’t even know about it?  While I could devote several pages answering that very question, I’ll do my best to sum it up quickly.  Building a house is difficult.  There are very few people who have the knowledge to do it all themselves and I may very well fall flat on my face in trying.  For me, that challenge is exciting, even if it is frustrating at times.  Because of this fact, the vast majority of houses are built by a massive team of “contractors” that under normal circumstances communicate very little with each other, if at all.  These tradesman are managed by a “general contractor” who uses building plans that were probably drawn up by an architect and edited by an engineer.  Although I was able to sum up the advanced framing techniques in a couple sentences, the small changes affect every single one of these workers.

Image result for photo of advanced framing vs traditional

The architect and the engineer must design the house from the very beginning so the floor joists and studs stack up within an inch of each stud (see pic above)  This puts a sort of limiting factor on the architect in regards to wall lengths and window placements that many are resistant to.  Next, the general contractor must be open to training the contractors under him because many of them will be unaccustomed to the framing.  The framing crew will be working with a different length of wood due to the single top plate, and have to frame completely differently than they are used to.  The electrician has fewer studs to attach electrical boxes to.  The drywall crew has fewer studs to nail the drywall to and may have to hang it differently.  The small changes ripple right on down the line and affect every single person that works on the house.  As contractors are paid by the job and not by the hour, they aren’t too keen on taking time to learn this new technique.  The fewer that learn it, the fewer that are available to teach it, and the cycle continues…

As I’m building solo, I have none of these issues.  I designed the house myself from the very beginning with advanced framing in mind.  Thanks to my mentor, who introduced me to advanced framing, I’ve never built any other way.  I saved money on lumber and nails.  I saved time with fewer studs to nail together.  I saved trees because of using less lumber (I’ll be using dense packed cellulose in the spaces where the studs would have been which is made of mostly recycled newspaper and denim).  I will save money on my energy bill each month (or be able to use a smaller solar array).  I even save time building because with the larger spacing between studs I can jump in an out of the house anywhere instead of using a doorway.  If you really want to save sustainably, advanced framing is the way to go.

 

Step 7b- Add Gravel, Vapor Barrier, and Rebar

Capillary forces are very powerful.  Have you ever been to a redwood forest and wondered how water gets from the roots to the leaves at the very top of the tree?  The answer is capillary force, and surprisingly, it works even more efficiently in concrete than it does in trees!  Scientists believe concrete has such powerful capillary force that it theoretically has the ability to drive water 6 miles upward against the force of gravity.  Wood maxes out at about 400 feet which is why you don’t see any trees get that high.  In an effort to curb these powerful forces, building codes require that a layer of gravel and a vapor barrier be placed underneath the concrete slab.  The gravel drains away any standing water, and the vapor barrier takes care of any water vapor. 

As you can see above, I have started adding the gravel layer inside my footing.  The long 2×12 boards act as barriers to prevent the gravel from occupying the “shovel footing” that is necessary to support the bearing wall that will soon be framed directly above it.  Once all the gravel has been added and compacted, the boards will be removed and a 12″ wide and 8″ deep ditch will be left behind.  It is much easier to create the ditch this way rather than shovel the gravel out.  When we pour the concrete for the slab, the concrete will flow into this ditch and the slab will be 8″ thicker along that line, giving added support to the bearing wall.  If you aren’t aware, a bearing wall means that it is supporting some of the weight of the house.  The entire roof of the house is supported on only two exterior walls, so none of the interior second story walls have any weight to carry. I could have supported the weight of the floor joists between the first and second stories in the same way, but I would have had to use special engineered I-Joists.  Instead, it was much easier to use two lengths of 2×12 joists and have them meet on top of one of the first story interior walls.  This wall is the bearing wall.

After all of the gravel had been added, I leveled it out and then installed the horizontal layer of Roxul as you can see above.  Keep in mind that the more insulation added now, the lower the heating bill will be in the future.  Investing an extra $300 now will quickly pay off in a year or two, and then I will reap the benefits every year after that for the life of the house.  Once the insulation was added, I ran a plate compactor around everywhere to ensure the gravel was well compacted.  Then I pulled out the long 2x12s to create the shovel footing as you can see below.

The last steps were to add the vapor barrier and rebar.  The vapor barrier comes in a large roll so it was simply a matter of rolling it out and cutting it to fit.  Wherever a pipe penetrated I used vapor barrier tape to seal the hole.  I tucked all the edges of the barrier in between the two layers of insulation.  The rebar I lined up in a neat, four foot grid and set it on 2″ chairs so it would end up right in the middle of the 4″ slab.