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 6d – Final Steps Before The First Pour

I passed my footing inspection today, which means that I am approved to pour my footings.  The inspector verified that my setbacks were correct and also leaned on the forms a bit to make sure they were sturdy.  He also made a visual inspection of everything to ensure that the dimensions were correct.  Overall it was a pretty easy process.  He signed my building permit and was gone after less than 10 minutes.

Over the last few days I had completed the final steps in preparation for the inspection.  These included forming the small point load footing for the stairway, laying out all the cold water supply lines, and setting up the utility sweeps for the electrical, heat pump water heater, and ductless mini split systems.  I also made a few minor adjustments to the forms to straighten out the rebar and make sure they were precisely squared and leveled, and laid out the anchor bolts.

 The inspector had made a small adjustment to my design during the permitting process.  He decided that the foundation needed to be strengthened at one particular point where the opening for the spiral staircase put a lot of weight on two walls of the first level.  At the spot where these walls intersected, he indicated on my plans that I was to pour a small footing under the slab measuring 16″x 16″x 10″.  I built a form for those dimensions using some 2×4’s and OSB, and lined it up at the correct spot so that the top of the form was 4″ below the top of my other forms.  I will pour this at the same time as my footings and then remove the form.  The 4″ above will allow enough space for the slab to be poured over it.

I’ll be running the hot water lines inside the “conditioned space” of the house, meaning that they will stay nice and warm at the same temperature as the house.  The cold water lines, on the other hand, don’t need that kind of insulation so I am running them underneath the slab alongside the rest of the plumbing I had already installed.  I will be using a hybrid type of water supply installation for the cold water lines, meaning it will be halfway between the “trunk and branch” method and the “home run” method.  The hot water lines will be almost exclusively home runs with one minor exception.

The trunk and branch method of water supply means that you have a main water line that travels through the entire house and wherever you have a fixture like a toilet or sink, the line for that fixture will branch off of the main trunk line.  The home run method means that as soon as the water line enters the house it is piped into what is called a manifold, where it immediately branches off into as many lines as there are fixtures in the house.  These branches pipe directly into each individual fixture.  When dealing with hot water lines, the trunk and branch system has a major flaw in that if you want hot water in one of the fixtures and the water currently in the trunk has already cooled off, you have to wait until all of the water in the trunk has exited the fixture before you get hot water.  This is not only annoying but also extremely wasteful.  The home run method uses more piping, but solves this problem, ultimately paying off in the long run.  For cold water lines this isn’t an issue, so I just ran the piping as efficiently as I could to reduce the amount of PEX piping I needed to buy.

The last step was to set up the utility sweeps, or chases.  These are conduits that are bent in 90 degree angles at very large radii, so when I am ready to run utility lines into the house I won’t need to cut a hole in the wall or reduce the amount of insulation I have in an exterior wall.  The electrical sweep will house the main electrical lines for the house.  The one for the water heater will house one cold line and one hot line as the water runs back and forth between the hot water tank inside the house and the heat exchanger outside the house.  Many houses have their hot water tanks in the garage which is extremely inefficient because the garage is unconditioned space and will cause the hot water to cool down faster.  The last sweep will house the refrigerant lines for the ductless mini split system as they travel between the heat pump outside and the fan inside.  I ran each of the sweeps from the location I had planned for each of them on an interior wall of the house down through the footing and out to the other side.  I next cut some small pieces of plywood to ensure that concrete wouldn’t spill over and cover the end of the conduits.

Here is the electrical sweep with the grounding electrode attached to the rebar next to it.

Here you can see the plywood that will prevent the concrete from flowing past the main plumbing outlet

Step 5 – Get a Building Permit

With the lot now officially fully improved, the next step is obtaining a building permit.  The county website had a nice and easy step by step instruction on how to go about working your way through the process.  The first step I completed a few weeks ago when I received my accepted Natural Resources Assessment.  The next step is to make a prescreening appointment with the county building office.  They will expect to review my construction documents, request any necessary changes and/or alterations, and address any concerns they have.  At that time I will go back to the drawing board and make any corrections they require before my final permit appointment, where I will present the updated construction documents and get them signed off by the inspector.  I’ve been working on the plans for months now, and am finally getting close to finishing them.  I’m quite sure that there will be some corrections requested, but I also don’t want to give the inspector a first impression that I don’t have a good grasp on what I’m doing.  Here is a sneak peek at what I have so far….

My goal is to complete the rest of my plans over the weekend and schedule my prescreening for Monday.  The only thing I have left to do is the details page (although it might need 2 pages).  It will take some time because much like the floor framing page above, there are lots of leaders (the arrows with explanations) and it takes time to scale the cross sections properly.

Step 4c – Ready For Another Inspection

And there you have it folks.  My $7000 high powered sprinkler system!  Hard to believe that underneath the plastic “infiltrators” you see in the background and 12 inches of soil, that spray is going to be the last step in safely disposing of my sewage.  Today, the septic designer brought over the last piece I needed, a “hose assembly”, and we hooked it up.  The hose assembly attaches to the pump at the bottom of the tank and makes three 90 degree turns before exiting the tank and going through the PVC pipes I assembled a few days ago.  

Now it was time to fill up the pump chamber with water and test the system.  It was necessary to fill up the chamber with water for two reasons. First, you never want to run any kind of water pump without water in it because air has much lower resistance than water and the motor will burn out without that resistance (so make sure you aren’t out of windshield wiper fluid!)  Second, the panel won’t operate the pump unless both the redundant off and pump on floats have been activated and I’m not too keen on climbing down into the tank and flipping them upside down by hand.  After ten minutes or so I had enough water in the tank to activate both floats and I turned on the power to the control panel.  The pump activated and we got the beautiful water show you see at the top of the post.  The septic designer called the inspector for an appointment tomorrow so I can replicate the display for him and he will sign off on it.  There will be a few more minor things to assemble once that is done but nothing I can’t get done by the end of tomorrow as long as the backhoe operator shows up.

Step 4 – Septic System

Standard treatment of sewage hasn’t changed much over the years.  Nature actually had it figured out pretty good before humans even attempted to manage it.  Given enough time, soil and the organisms that inhabit it are extremely adept at breaking down harmful toxins and dispersing the safer compounds into underground waterways.  The only thing a septic system does is harness this awesome power.

Designing a proper system starts with a soils test and/or “perc” test.  A soils test involves removing a deep core of soil and analyzing what appears in the different layers.  Soil is then classified into sand, gravel, loam, clay, and all sorts of combinations of those types.  A perc test involves filling a deep hole with water and timing how long it takes water to percolate through the soil at the bottom of the hole (the soil must be prepped by soaking it thoroughly first and most counties require you to have a license to complete the test).  Both tests can give a pretty good indication of how well a particular patch of soil will perform at breaking down the “effluent”, which is what sewage becomes after sitting for a period of time.

Soils Test

In my state, the soils test or perc test must be completed by a licensed septic designer.  The designer I hired charged $150 and found my soil to be “sandy loam” for the top inch and “medium sand” for the next two feet until reaching the water table at 28″.  This is the depth at which dry soil becomes saturated with water due to an underground spring.    The county and state health codes dictate what kind of dispersal system can be used for a given type of soil, and for my great soil and water table depth they allowed me to use a gravity distributed system, which is the simplest type.

Perc Test

The next step in the design called for locating the area of the lot where the drain field would be located.  Health codes dictate setbacks for the field of 5′ from property lines, 10′ from water lines, and 100′ from natural water supplies.  I have a natural canal on one end of my property, and the 100′ setback took up a substantial amount of the lot.  The drain field needed to be 400 square feet, and there also needed to be a reserve field of the same area set at least 6′ away from the main field.  I had a problem here because it was impossible to fit both fields into the setbacks.  Fortunately, by using the next system up from gravity I was able to use smaller fields that fit within the setbacks.

The type of design I will be installing is a pressure distributed system.  It’s basically the same as a gravity type system but with the addition of a pump.  This balances the distribution of effluent more evenly across the field and thus allows for a smaller area.  The sewage from the house exits the main drain pipe and enters a 3 compartment concrete septic tank.

The first compartment is aptly named the trash chamber, and allows the sewage to separate into solids on the bottom, a layer of sludge on the top, and a cleaner liquid in the middle.  This liquid is allowed to enter the second compartment, called the digestion chamber.  In order to exit this chamber, the sewage must decompose into small enough particles to pass through a filter.  In the last compartment, the clarifier chamber, the pump sits at the bottom.  When the level of liquid in the chamber causes a float to reach a certain height, the pump turns on and pumps some of the liquid out of the tank and through a pipe to the drain field.  There are two more floats, the first to ensure the pump doesn’t run too often and the second to sound an alarm if the pump isn’t working and the tank is getting full.  

It’s a relatively simple operation, so I’m planning to get it all done in less than a week!  In just two days from now, a local contractor with a backhoe will be coming out to dig a deep hole for the tank.  I will check the depth as he digs and ensure it is correct.  Around midday a crane will arrive and the tank manufacturer will drop it into the hole.  We will immediately begin filling it with water while the backhoe gets started on digging the main field.  It’s very important to get the drain field completely level and ensure that it is at precisely the correct depth.  If you go too low there won’t be enough soil to break down the effluent and you can’t just add soil back in because then it will be classified differently.  If you don’t go deep enough there won’t be enough soil to protect the effluent from the human activity above.  The health inspector must pass off the installation of the design and he will pay very close attention to the depth of the field.

In the few days following I will be assembling all the necessary pipes that lead to and from the tank, the floats that go inside the tank, and the pipes that will lie inside the field and distribute the effluent evenly across the entire area.  These lines will be covered with large plastic tunnels called gravelless chambers.  The last step will involve wiring the control panel to the floats and pump and hooking it up to power.  My goal will be to get it all done within 5 days because that is the day the health inspector comes out.  If I don’t finish I will have to wait another week!

I was very pleased with the deal that the septic designer got for me.  You can see the total cost of the system by clicking on the Project Budget link on the home page.  He is also going to check up on me throughout the installation to ensure I’m getting everything hooked up correctly.

Step 3b – Wiring and Inspection

Electrical wiring seems very complicated but its actually pretty simple.  The catch is that a mistake could possibly kill you.  Fortunately, when you are dealing with new construction, the power isn’t hooked up yet so you don’t have to worry about that.    The basics behind modern electricity can be pretty complicated, but here is a quick rundown.  Standard residential service uses alternating current with two 120 volt currents running in opposite phases.  Think of it like two pedals on a bicycle.  They are on opposite sides of each other but they can work together when you need them to.  Large appliances that need all 240 volts available can use a double breaker and take advantage of the added power.  Most normal circuits just utilize one phase or the other depending on where the breakers are situated in the panel.  As you can see in the photo at top, I have one 30 amp circuit powering the trailer using one phase and a 20 amp circuit for my tools on the other phase.  Within a couple weeks I hope to add two additional circuits on opposing phases to power my septic system.

As for the wiring of these circuits, the first step was to bring power from the utility company’s stubout to a meter socket.  The utility company will splice these wires to the ones they have in the stubout and put a meter in the meter socket so they can properly bill me for the power I use.  They are not allowed to complete these tasks until I have a sticker placed on my panel by the state electrical inspector.  In many states the building inspector does the electrical inspections but in Washington they are completed by the department of labor and industry.  According to the NEC (National Electric Code), you need to use size #4 copper or #2 aluminum wires to power a 100 amp service like the one I am installing.  Because these wires are run underground, they are required to be URD (underground residential distribution) conductors.  I used aluminum because it was cheaper.  Three wires are used, one for each phase of the AC current and one for the neutral wire where the power returns.  Think of electrical power like a river powering a water wheel.  If there is no place for the river to flow it won’t move and the wheel won’t move either.  Likewise, electricity won’t work unless it has a place to go and the neutral wire provides this path.

From the meter socket, the same URD wires are used to run the two “hots” and one neutral to the breaker panel.  Inside the panel, clamps are provided that connect to large metal plates for the “hot” wires, and a long metal bar for the neutral wire.  For every circuit, a breaker is connected to one of the metal plates and a white neutral wire is connected to the metal neutral bar.  The hot wire for the circuit is then connected to the breaker and the circuit is complete.  As you can see, I have one circuit to power the trailer that connects to a 30 amp breaker and one for my tools that connects to a 20 amp breaker.

There is a third wire on each circuit that is called the ground wire.  This wire is a relatively modern innovation for safety reasons and isn’t necessary to power either of the circuits.  Many elements have the ability to conduct electricity, including the human body, and electricity acts just as water does in that it will take the easiest path available.  A properly grounded electrical system provides a path with very little resistance so that, in the instance of a wire coming loose and briefly contacting a surface that conducts electricity, the surface charge will continue through the grounding system rather than remaining on the surface and electrocuting the next person that touches it.  The ground wires on the circuit are connected to a “grounding bar” inside the panel that is also connected through a copper wire to a 10 foot long copper rod that is buried all the way down into the earth.  Using our water analogy, this would be as if there was a water slide leading to a pool.  Some of the water might splash up onto the sides of the slide, but gravity is going to eventually draw it down into the pool.

So that basically covers the wiring of the system.  The hardest part is deciphering the NEC to figure out what type and size of wires to use.  There are many different kinds of conductors (THHN, THWN, XHHW, URD) which are basically single insulated wires, and then there are many different kinds of cables (UF, NM, SE, USE) which are several conductors independently insulated and bundled together and then given a second layer of insulation.  With the wiring completed, I was able to call an inspector in and he passed me off and put a yellow sticker on my service panel.  The utility company won’t connect the power without the sticker but now that I have it I can call them up and get connected.