I shouldn’t have waited so long to write about the plumbing. We did the majority of the work back in November and it’s not fresh in my mind. I will do my best to recall the steps.
The first step was convincing dad that PEX was the way to go. PEX was not commonly used when he was in the building business so this was a learning experience for both of us. I had originally planned on going with a “home-run” layout, using manifolds for the hot and the cold but, as I started laying the foam in the floor, I realized how hard it was going to be to cover the pipes and, as a home-run layout has many more individual pipes, it would be very time consuming. Plus, I didn’t really have the space in the interior walls to house the manifolds. Dad was against the home-run setup from the start so he was very happy I came around to the traditional trunk-and-branch layout. FineHomeBuilding.com has a simple explanation of each system here. The benefit of using the trunk-and-branch is that only the main lines are run through the floor joists with short lines off them to each fixture. With such a small house, I really don’t see any downsides to this method. The reason we chose to run the pipes through the floor was because we had a deeper space to insulate there, 6″ as opposed to 4″. We did shim the shower and toilet wall out to accommodate the insulation and the pipes. We also shimmed out the interior closet walls to make room for where the sink PEX lines overlapped the PVC drain.
Thankfully, while I was still in the design phase, dad clued me in to how much simpler and cheaper it’d be if I kept all the plumbing on one end of the house (i.e. bathroom, kitchen, and water heater as close as possible). With my bathroom sink being about 4′ of pipe away from the water heater, I have instant hot water. Ironically, I never use hot water in that sink. Some people seem to be sketched out at the idea of having a bathroom so close to the kitchen… I don’t see what the problem is if you have a door between the two. Then again, I live alone…
We borrowed a cinch-ring crimper tool and a tubing cutter from my dad’s friend. The connections are very easy to make, it just takes a little muscle. After seeing how fast everything connected, dad was a believer.
We put together a gauge to check for leaks with a PEX fitting on one end and a ball valve and compressor nipple on the other end. We capped the ends of the pipes, connected the gauge, hooked up the air compressor, filled the pipes to 100 PSI, and shut the valve. I nervously kept checking the gauge. Overnight it dropped about 15 pounds so I filled a spray bottle with soapy water and methodically sprayed every fitting. I remember thinking “this doesn’t work, it’s not high-tech enough,” as I had sprayed all the fittings and didn’t see any bubbles. I called dad up and explained the situation and he asked if I had sprayed the gauge. I had not. Dad was the brains behind the gauge but the problem was he left me to put it together. Sure enough, I sprayed one of the seals on the gauge and bubbles galore (that sounds like a Bond girl). We swapped out the fitting and the pressure held!
I hired a plumber to make sure we were up to code and he connected the rough plumbing PVC drain and vent pipes. The shower P-trap hangs below the foam in the floor and I wrapped that with fiberglass insulation. If I had to do it all over again, I would probably build the floor up or at least put the shower on a riser so I could keep the plumbing within the floor and insulate around it better. The sewer drain pipe is suspended from the trailer frame at a 3/10 pitch and connected to mom and dad’s new septic tank by a pipe that comes up through one of the boxes we built into the slab. The drain pipe was a major source of stress for me when we were moving the house onto the slab. There was barely any clearance and I would definitely have to modify this if I planned on moving often. The main water pipe comes up through another box in the slab at the opposite end. This pipe runs underground into my parent’s basement and connects to their pump.
When the sheetrock was up and we were ready to put in the shut-off valves on all of the fixtures, a lot of time had passed and we had returned the PEX tools. I ended up borrowing a crimper from my niece’s mom, Carri (the noted out-law whom I still call sister). It had belonged to her stepdad, Tony, who passed away. I feel fairly confident in saying Tony would’ve loved the tiny-house movement and would’ve been my go-to guy for all things plumbing. He was dedicated to his trade and I am honored to have been able to use his tools and have him on the job, in spirit anyway.
My water heater’s capacity is 30 gallons, which is more than enough for me. My showers average around 5 minutes, I use the “ecowash” setting on my washer, and I hand wash my dishes as I dirty them. I’ve never understood why anyone would waste precious space in a tiny house with a dishwasher. Even if I washed every dish I own at the same time, I still wouldn’t have half a load. I guess it would make sense if you were washing baby bottles or had a large family…
I thought maybe plumbing would be my forte, and I do like designing the layout of the pipes, but I can’t handle the anxiety of possible leaks.