I am pleased to advise that the installation of the exterior water/air barrier, and 6″ of exterior ROXUL mineral wool insulation panels is going well. Over the last 2 weeks I have completed the first storey of the south and west elevations. The encouraging part is that the west elevation looks like it will only take 3 days total compared to the week plus the south elevation took.
Now on the south, I had a lot of figuring out to do. We had not yet chosen exterior lights for beside the exit doors. The choice would effect where the electrical box would be located as I want the top of the lights to line up with the top of the doors. I also had to secure and seal the final french door (for the office) before I could detail that opening. I then designed and sourced some walkway lighting that will be mounted approximately knee height on the wall and shine down and cast a warm glow along the walkways flanking the house. Finally, the south elevation contains one of the two basement foundation wall science labs and I needed to figure out a way to terminate the sensor wires and also install the water injection system that will be used to wet up the ICF and mineral wool insulation under controlled events.
By the time I got to the west wall, I had figured out all the steps and also easiest way to install the ROXUL panels using the table saw to accurately cut the required sizes and angles. I also discovered that the primer for the foil faced membrane made an EXCELLENT adhesive to stick the various cut insulation panels together, removing the need to use auxiliary screws with plastic washers to hold panels in place temporarily until the furring strips could be installed.
Now, I did not want these clips attached to the foundation were they would have to penetrate the waterproofing membrane. So I designed this system that clips to the sheathing above grade. I sandwiched an aerogell gasket (R4 for only 10mm) between the S.S. clip and the sheathing to reduce thermal bridging. It is important to ensure the aerogel is encased in a wrap of some sort to retain all the microscopic ‘powder’ that make up its high R value.
With the base of wall detailed I could then start to install the wall insulation. In our design, this is two layers of 3″ ROXUL ComfortBoard 80 with staggered seams.
One of the most difficult parts of this installation was going to be how to ensure the battens were all installed at the same correct elevation (otherwise it would make installing flashing level and ensuring a nice site line difficult). This was solved by installing a rigid long board – header – I used left over blocking I-joist and some dimensional lumber, at the top side of the 1st length of battens. I set the board off of the sheathing by the depth of the exterior insulation with blocks I cut out of left over lintel and post pieces. Now I just had to line up the battens with the top of the header and with the studs (later are easily visible due to sheathing nailing pattern visible above the membrane), and screw to the header to ‘hang’ them in place. Installing a second screw in through the batten into the header ensures the batten stayed plumb. This allowed me to install the full batten system and the bottom bug screen without screwing any of it into the wall. For me this was a necessary step so that I can still slip in and attached my base of batten flashing a little later (a sequencing issue because I will have the flashing corners bent up by a pro with a brake to ensure a nice finished look). Even if I did not have the base of wall flashing issue, this method of hanging the battens made their installation MUCH faster and easier. On the west wall, I installed the mounting board and all of the full length battens for the wall (including pre-drilling holes at 16″, counter sinking, and treating with wood preservative) in under an hour.
I mounted the electrical boxes for the exterior pathway lighting to pressure treated 3/8″ plywood strips. I then screwed through the battens into the plywood strips with spacers between the plywood and battens to maintain the required setback so the box sat flush with the exterior plane of the to be installed siding. To minimize penetrations, I looped the conduit down under doorways on the exterior side of the wall to carry on the circuit on the other side of the entrance. You can also see the furring strips and perforated stainless steel bug screen installed in the above photo. Later a base of rain-screen flashing will be slipped behind the furring strips and screwed through the insulation to the previously installed horizontally 2×2 blocking. This prevents fasteners from penetrating the sheathing membrane and also prevents the thermal bridging that would be present in a cross cavity metal flashing.
Confession! – As I was preparing this journal entry, I realized I have forgotten to install the foil faced membrane that is to provide cross cavity evacuation of any water that gets behind the cladding and insulation. This was to install about the same height as the lighting circuit. I will need to figure out a way of cutting out the insulation to install it now on these two completed walls. 🙁
Somewhere along the way I came across the below method for installing a pull chord in your conduit.
Part of the recent effort also involved terminating the building science lab installed into the foundation.
I brought the piping for the injection ports and the sensor wiring to the area of a to be installed PVC electrical box (12×12) that will be mounted flush with the surface of the sidewalk and sealed with a gasketed stainless steel lid.
Also as promised, here is also a photo of 2.0 diameter 7″ 90º duct elbow. As you can see, this takes up quite a bit of real-estate. I still have to go through my routing of the ducts and ensure there is enough room for this elbow at all locations before placing the order for these special order (and expensive) fittings.
I will continue working on the exterior insulation for several weeks more and then start on the siding. There is also some exciting news about progressing on another major milestone, but I will delay reporting on it till later for fear of jinxing it.
Thanks for visiting!
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