Plumbing rough-in needs to happen before electrical and mechanical rough-in as drainage requires specific placement and gradients whereas electrical and mechanical have more routing flexibility.
Grohe Sense Guard
As the hot water cylinder will be buried away in the dead-corner of the kitchen cabinets I wanted to be able to detect water leaks and automatically shutoff the water. I went with Grohe’s Sense Guard system. I needed two of these for the City Water and Rainwater supplies. There are a bunch of valves so each unit can be bypassed and maintained.
Once installed and connected to WiFi and my phone app I’m able to receive notifications of water leaks, remotely turn water service on and off, and track water usage in gallons, water temperature and pressure.
Bathroom, shower, and kitchen hot and cold lines were installed as home-runs to manifolds using 1/2-inch PEX. The toilet, laundry and outdoor faucet were run as 1/2-inch purple PEX to a rainwater manifold. Each homerun line can be individually isolated with a valve located at the manifold.
The back wall of the bathroom is framed out an additional 6-inches. This provides space for an in-wall tank for the wall-hung toilet and for routing shower lines without intruding into the insulated 3.5-inch framing cavity.
Toto provides a detailed framing plan for their wall-hung toilets.
There is an electrical outlet installed to left of the toilet for a Toto bidet toilet seat.
The toilet and shower are vented through the roof. The roof penetration was sealed using a Roflex 30 gasket from 475 High Performance Building Supply and this was then sealed with Prosocco liquid membrane. The basin, kitchen, and laundry drains are vented using Air Admittance Valves as there was not enough room to run vents through walls.
I used Aquor’s “House Hydrant” connected to the rainwater manifold for the outdoor faucet. Aquor is based in Washington state. https://aquorwatersystems.com/
I’m using a pocket door between the bathroom and kitchen; no space to swing a door.
Johnson Hardware vs. Hafele
Initially I went with a door frame and track provided by my door/window supplier – based on a Johnson Hardware 1500 frame and mechanism. $267 for the frame, track, slider mechanism, and 2-foot wide door panel. However the metal bracing was lightweight and the framing had a lot of flex. Furthermore Hammer & Hand have a guide to installing pocket doors and they explicitly say:
Do not use Johnson Pocket Door Kit 1500, 1500HD, 1500SC, 2511, or 2000
Instead they recommend using Johnson Pocket Door Kit 2710 or 2711. They don’t give any reasons however I’d think it’s about durability.
My other concern was about maintenance of the track. All of the Johnson Hardware frames would require the wall be taken apart to replace a damaged track. Presumably the tracks would be good for a couple of decades or more of life, however, that didn’t seem acceptable to me.
After more research I settled on a Hafele frame and track. The framing is made of a sturdy wood/metal composite and the track slots into the cavity with no hidden screws at all allowing the track to be removed and replaced without cutting into the wall.
Hafele Slido Pocket Door
I bought the:
Hafele frameset from The Builders Supply in Austin, TX “HAF_94272000 Hafele 942.72.000 Pocket Door Frame Set, Slido” for $309. (this kit comes with a track – no need to purchase the track separately)
Soft-close slider set from Cabinet Parts “Slido Classic 40-P Fitting Set with 1 Side Smuso Soft-Close HAF-940.43.000” for $133.
The kitchen and bathroom are located on a raised platform providing 2 feet of utility space under the kitchen and space to stow a Queen sized bed under the bathroom.
My builder constructed the floor framing first and tied this in to the wall studs. The framing is supported down the center where the bathroom/kitchen wall will go by a 2 foot high wall built on a pressure-treated 4×4 resting on a rubber membrane.
A space was left in the kitchen corner for the hot water cylinder. The kitchen units will be built in such a way that the tank can be removed and replaced during the life of the kitchen.
There were are couple of options for the floor/wall sequence. i) Install the internal wall framing then lay down plywood sheathing (3/4″) between the walls. ii) Install the floor sheathing in one continuous run and then build the walls on top of the floor sheathing. The builder recommended ii) floor sheathing first – there are several advantages – better isolation of the bathroom and kitchen from the utility space and bed storage area below. Better floor strength.
I was wondering how the internal walls would tie in with the rafters. One part of the bathroom wall aligned with a rafter so that was easy. Where they didn’t align he installed blocking between the rafters and the attached the top plate to that. Because of the angled roof it was easier to install one stud at a time rather than build as a complete wall on the flat and then raise into place.
Bed cavity and shelf for media equipment/TV etc on the right; closet on the left protrudes back into the shower space.
With the electrical rough-in date approaching I needed to get the doors and windows installed to make the structure weather-proof. The builder scheduled a day for his crew to come on-site and do the installation.
Building window and door bucks
The window and door openings were not framed with bucks to extend out past the exterior insulation layer as I only made the decision between innie/outie windows after the structural framing was complete. So the first task was to build frames to extend out the door and window openings.
The builder had his crew build the window bucks as a complete frame that was then screwed onto the structure as one piece. This allowed for an easier and higher-quality build than tacking separate pieces of frame directly to the structure.
I flashed the bucks to the sheathing using Prosoco Gap and Crack filler and Fast Flash.
Tremco ExoAir Trio
From the Hammer & Hands blogs I picked up on a new system for mounting and sealing windows and doors based around a Tremco product.
ExoAir Trio is a self-expanding joint sealing tape that is used in place of traditional spray-foam sealant to weatherproof windows and doors. It was my the first time to try this technique and the builder hadn’t used it before. We ended up using a combination of traditional shimming , Tremco ExoAir tape, and spray foam to install the windows. Now that I know how it works, I would be able to much more easily use this Tremco product for any future window installs.
Here’s the Hammer & Hand video demonstrating how to set a window using Tremco tape and Shim Screws.
My observation is that this is a significantly easier method for aligning and installing window frames vs traditional methods and that it provides a significantly better weather and air seal than using spray foam.
Installation of the living room window
Installation of the doors
The builder recommended a metal sill pan under the door sill and the window guy at Western Pacific agreed. It’s cheap compared to the cost of a door, it’s good insurance against water leaks through onto the floor, and although not required by code in Portland, it’s mandatory in a bunch of other states.
Based on this experience my suggestions are:
The Tremco tape can be ordered in 3 different thickness, each thickness being rated for a different sized gap between the window frame and the rough-opening: 3/16” – 3/8” gap, 1/4” – 9/16” gap, and 3/8” – 3/4” gap. I had a range of gap sizes so I went with the smallest thickness tape. As it turned out this was a very tight fit (too tight) around the door, good fit for the small kitchen window and the sides of the large window, and way too small for the bottom and top gaps on the large window. It only comes in lots of 3 rolls and it’s expense to order a bunch of different sizes for a one-off project like mine. So my suggestion is when sizing your windows/doors and rough-openings, try to keep the gaps top/bottom/sides consistent so you can use just one variant of Tremco tape. If you end up with a large gap as I did on the large living room window then you can always use spray-foam after the window is installed to complete the gap sealing.
Don’t shim in the traditional way by pushing shims all the way through the opening. You need to ditch that method completely. It only creates a path for water and air penetration through the frame which is exactly what you are avoiding by using this Tremco product. Also you don’t have time to mess around shimming once the tape is in place and starting to expand. Instead use the shim technique demonstrated in the Hammer & Hand video above where the bottom sill is shimmed part-way through the foam layer only and the shims are set perfectly level before you apply the tape or install the window.
It’s really important to cut the tape longer than each frame dimension and to bunch up the tape at the ends of the sill as shown in the video. On those corners where I did not cram enough tape into the corner, the tape started pulling back from the corner once it started expanding, This left a couple of corners with a large gap in the expanded foam tape that I then needed to spray-foam to seal.
Make sure the white side of the tape goes to the interior. It’s a partial vapor barrier and you want to direct any water outwards, not inwards.
Use shim screws to fasten the window to the framing and to adjust the horizontal left/right position. (You will have already got the vertical top/bottom alignment correct by using the correct thickness shims on the bottom sill before applying the tape.)
It took over a week for the tape to fully expand and close some of the wider gaps – perhaps due to the cooler weather.
You can buy Shim Screws from Conservation Technologies:
The door and window products were specified on the architect’s plans: Simpson french doors and Marvin windows. The Marvin windows are well constructed and weather-tight – important given the likely exposure to weather due to the short roof overhangs of the “English Cottage” style. On the overhand Marvin doors would have been expensive and Simpson was a good balance of cost and quality. Velux was specified for the two skylights.
The builder recommended Western Pacific in NW Portland as the supplier. They are a large organized building materials supplier located in NW Portland. I scheduled meetings with Western Pacific’s window and door people and ordered the doors, windows, and skylights. The skylights came within a week, the windows and doors around 3-4 weeks. I provided the door lock to Western Pacific and they drilled for the lock-set and hung and fitted the doors in their shop before delivery. (On installation, the door alignment with the frame was pretty much spot on.)
The window frame is set back inside the exterior insulation layer so it’s in a warmer location, less risk of condensation on the interior glass
The window is recessed away from rain and wind
The architect suggested that the innie windows create deeper and more interesting shadow lines on the building facade
The advantages of Outie Windows:
Most American homes are built with Outie windows so it looks normal
The main house has Outie windows (there’s no exterior insulation so the shallow wall depth means outie/innie choice doesn’t exist). The ADU details are supposed to match the main house as it’s in a Historical District.
It creates a deep interior sill that provides useful interior space in such a small structure
The French Doors are outswinging so they will be Outies by default. So Outie windows will align with the plane of the doors.
So I went with Outie windows. As the rough framing had already been completed by the time I made this decision, this narrowed my installation options.
The platform is built – 2x6s on hangers. The bathroom is on the left, kitchen on the right. The bed slides under the cavity to the left. The right will be used for plumbing, and electrical runs.
The floor is left open in the corner of the kitchen for the hot water tank which will slide in under the kitchen counter and rest on the concrete slab.
I added beveled siding strips onto the window sills to provide a drainage slope to the exterior. The window rough-in had already been flashed with Prosoco Gap & Crack Filler. I layed out three stripes of Prosoco FastFlash and then tacked in the siding.
As this reduced the rough-in vertical dimension by 1/4-inch I updated the window supplier (Western Pacific) with the new rough-in size.
The north side of the ADU is fire-rated as it’s within 3 feet of the property line. This means DensGlass paneling goes over the ply sheathing on the north side, the first 4 feet of the upper roof deck will be fire-resistant plywood, and the interior north wall will be covered in fire-rated gypsum rather than standard drywall.
The DensGlass is not structural; that’s the job of the underlying nailed plywood. So the panels are screwed in rather than nailed.