Monthly Archives: July 2017

Getting wrapped up in a thick wool blanket

July 16, 2017

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.

Step 1 – Ensure your WRB/AB sheathing membrane is well sealed to foundation waterproofing membrane. The seam seen at the dotted line is interface with framed wall and poured foundation.

Step 2 – Install clips that will hold the protection board against the foundation insulation that projects above grade.

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.

The aerogell comes in 1.5″ wide strips. You can easily cut these in half with a new construction snap blade and then re-wrap them with a good quality sheathing tape.

Step 3 – With the clips in place, fill in the rest of the foundation insulation to the height of the horizontal blocking (blocking will be used to attach the base of rain-screen flashing without penetrating sheathing membrane)

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.

Our design includes covering over the outside of the window frames to provide a better overall installed R-Value as well as cleaner lines with less of the window frame showing.

I used dimensional lumber and various thicknesses of plywood as guides for cutting the various notches in the panels to fit around the window frames and buck-out that they are attached to.

To provide a backing for the siding return that will form the jamb and head window returns, I fastened fibreglass angle clips to the window frame. This was instead of the much larger wood bucks that would be needed, and represents a lot less thermal bridging. I am not sure yet how I will attach the siding returns to these clips. I may do with visible stainless fasteners or hidden S.S. staples that are filled over and stained.

Base of windows has secondary sill membrane that sheds water to outside of insulation surface.  The Protecto-Tak spray adhesive is used to secure the membrane to the mineral wool but also made an excellent adhesive to secure pieces of mineral wool to each other.

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.

Installing a temporary header greatly simplifies the installation of the furring strips. It allows you to ensure all are at same elevation and also all are plumb. Once I start securing the strips below with screws at 16″ centres, I can disconnect from and remove header. This method also allows to easily locate the studs as the membrane is not yet installed at the top of the furring strips.

Mounting exterior lights is easy with this method taught at the BCIT BLDC 3060 lab course. The outdoor box is back mounted to a threaded nipple. This makes it really easy to seal around the wiring that is fed through the inside of the nipple and then to seal the exterior of the nipple to the sheathing membrane. I used the R-Guard products for this. (Just make sure you use an electrical GRC – Galvanized Rigid Conduit – nipple for this application to keep your electrical inspector happy.  A plumbing black steel nipple will not do!)

The inside of the nipple is strapped to a stud or blocking for a rigid installation with no additional exterior attachment/support of the light box needed.

The box can be threaded in or out on the end of the nipple to align with the face of the siding.

Exterior path lighting conduit and boxes carved into exterior face of insulation. The plywood also simulates where I will install cement board panels to protect the insulation on the foundation that projects above grade.  The top side of the panel will be retained by the S.S. clips and the bottom side will sit into a formed grove in the sidewalk.  This system will allow the panel to be replaced over time as it breaks down.

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.  🙁

I found the easiest way to carve the space for the conduit was to cut the depth with a knife and then ‘carve’ the space out using a piece of conduit.

This method also worked for ‘drilling’ the required holes where the conduit ran perpendicular to the insulation panels.

Somewhere along the way I came across the below method for installing a pull chord in your conduit.

Tie off a paper towel, or something equally as fluffy, to some pull string and install at the furthest end of the run.

At the other end of the run, draw air with a tightly fitting vacuum hose.

In seconds, you can pull the chord through any length of conduit.

You must use separate conductors with no outer jacket when installing inside a conduit. To prevent having to run the conduit to a box to convert from the conduit’s individual conductors to a normal Loomex jacketed cable, just install a strain relief coupling at end of conduit run. Run Loomex up to the clamp and then cut the outer jacket off for the remainder of the conductors that will run within the conduit.

Part of the recent effort also involved terminating the building science lab installed into the foundation.

This short stub will provide the water injection for the mineral wool layer. Unlike the ICF injection, the mineral wool should disperse the water entry over a larger area.

In this photo you can see a moisture/temp sensor just above the dirt, followed by the copper injection port for the ICF, and then finally at top the Roxul injection port. The building science lab encompasses 6 columns located with three on the south elevation and three on the east.

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.

7″ 90º Duct Elbow with 2.0 centre-line radius bend

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!

“We have enough people who tell it like it is—now we could use a few who tell it like it can be. ” —Robert Orben (born 1927) Magician, Comedy Writer

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Ducks in row – Finally!

July 2, 2017

I have now progressed far enough on finalizing design and sourcing materials that I will be able to physically start work at the job-site this week.  Last week involved finishing off the cladding design and a series of vendor visits to pick up the following:

  • 3/4″ x 2.5″ x 8′ Pressure Treated Furring strips. I was looking for 3″ wide strips to make it easier to keep the plane of the furring strip face even, but have been assured that the 2.5″ will work with a little bit more effort.  The 3″ are a special order where I would need to order a minimum qty of 640 pcs at $3.45 ea.  I was able to find the 250 pcs I need, in a 2.5″ wide configuration, from Poco Building Supplies for $2.02 ea (was old stock purchased before the plywood prices shot up).
  • Flashing Package.  I finalized and ordered my flashing package from Eagle Sheet Metal in South Vancouver.  They are a small family run shop that do fabrication (and installation if needed).  They had excellent service and a fast turn around.  Their pricing was comparable to the other recommended flashing shop but they were more accommodating in being able to also fabricate the stainless profiles. Thanks to Alana for processing and turning my order around quickly.   I have 8 flashing profiles with five of them in 24 ga. Kynar Dark Bronze and three profiles in Stainless Steel.

The Kynar material is a much better finish than the standard you typically see at the lumber shops.  This finish along with heavier 24 ga. will allow these flashings to stand up well to decades of UV exposure and outdoor rigours. The stainless profiles are per 2, 4, & 5/A15 details on the A15 Flashing Summary drawing.

2/A15 is a cross cavity clip that will attach to the wall exterior sheathing and contain the top end of the cement protection board I will have at base of wall that protects the foundation insulation that projects above grade.  I chose stainless for this profile to reduce the thermal bridge it represents (conductive path through insulation layer).  I will reduce this bridging further by sandwiching a 10mm areogel insulation strip by Proloft between the clip and the sheathing.  This 10mm strip represents an amazing R4 thermal resistance.  The strips can be purchased from Convoy Supply in Surrey location for $9.71 per 56″ long x 1.5″ strip.  I needed 3/4″ strips, and the manufacturer had recommended using an angle grinder with cutoff wheel, but this just made a mess.  The best method was to just use a straight edge and a construction snap blade to easily cut through the material.  The areogel is encapsulated in a rigid shrink wrap.  This is of course compromised if you cut in half.  So I just re-wraped the cut strips in some Tyvek sheathing membrane tape.  The encapsulation is to keep as much of the micro bubbles as possible contained within the fibreglass substrate.

Cross Cavity Stainless Retention Clip shown in red.

Profile 4/A15 is a perforated stainless and will provide the bug screen at the top and bottom of the rain screen gaps (much more durable and attractive than the plastic mesh you buy at the lumber stores, also much easier to install).  Profile 5/A15 will provide the bug screen and integrated wind clips (by locking into hem of Kynar flashing) for window sills, heads, and second storey base of wall locations.

I have all flashing and proloft on site now and will start installation this coming week.  I did some test flashing s-seams last week and have realized I am not very good at making these look neat, especially with the heavier 24 gauge material.  I had planned on hiring Geoff Kirkpatrick from RDH to come and fabricate my standing seam corners anyway, and will now have him also fab the s-joints in the more visible base of first wall locations. Hopefully with his guidance, I will be able to make the more remote upper floor seams look good enough from grade.

  • HRV 2.0 radius special order elbows.  I have picked up a sample of the 7″ 90 and 45 custom elbows and will work during some evenings over the next week or so to ensure their much longer length fits into all of the tight spots I have with my HRV duct routing.  They come with a hefty price tag with each 7″ 90 coming in at $46 each from Ecco heating products.  For my system, this works out to $2700 + tax for just the 45 & 90 elbows.  The main fittings and pipe are another $1500.  And my HRV unit itself will probably come in around the $3K mark.  But this is still well below the reported costs of the proprietary systems used by Zehnder and other high efficiency systems.  With the large diameter ducts and the gentle 2.0 radius bends, I should have very low pressure drops throughout the system leading to increased comfort and reduced energy costs.
  • Cladding – I have now finalized the cladding design including feature walls that we will place at the front of the building.

I am still working towards sourcing the cedar from Coulson. They have given me some great pricing but the engineered siding is still a lot more expensive than the solid cedar material.  However, the engineered product is reported to be more stable and less prone to cracking and twisting/warping.  I have priced out the finalized cedar takeoff at $16,400 (Coulson can provide the following lengths: 2′, 3′, 4′, 5′, 6′, 7′, 8′, 10′, 12′, 14′, & 16′ – the 16′ will have one seam within its length).  It is much cheaper to buy in the lengths needed than to say buy it all as 16′ stock and cut on site as needed.  I spent a couple of days planning out the cut list to come up with the exact sizes needed around the dwelling.  I also bought a sample board from Dicks Lumber (who sell it but at MUCH higher prices) and am testing various stain applications for the desired finished look.  We want to preserve the richness of the cedar and not let it ‘grey’ but at the same time, want to try and blend some of the variability found in the grain colouring of even one strip.

We are looking at mitred corners at window penetrations and outside building corners.  Yes I know, mitred corners have a history of opening up.  But that is typically with solid cedar strips.  I am hoping that the engineered material would hold up much better and we will also use exterior adhesive and pins to lock in place.  We will still have a fallback down the road of adding some trim over top of the mitred seams if they do nor perform well and I will also line the corners behind with flashing to prevent water ingress.

For the feature walls we will look at a cement board panels.  Currently the front runner is the Illumination Series from Nichiha.  These are a thicker panel than the standard Hardie and seem to have a better selection of colour matched trims.  The physical appearance of the product also looks more high end compared to Hardie and the Illumination series allows you to colour match to ANY paint chip colour.  We are looking at a darker cool grey to offset the warmer red tones of the cedar.  I have looked at the ‘more sustainable’ panels made from compressed paper fibres, but my research has indicated the colour fastness of the product is questionable.  It is also a LOT more expensive than the cement board alternative.  In the end, this is going on a fairly small percentage of the house, so if the product does not work out, we can replace with something different down the line.

I will post some photos as I start installing the exterior insulation and cladding and also of the custom elbows in the next week or so.  I am also going to do my best to start updating the photo gallery on the site.  Sorry folks, just been too busy and tired.  I will get to it.  As far as the main project details under the project design tab of the site.  I am afraid that most of this will not get updated till the end of the project when I have a lot more time to illustrate the various assemblies and write up their descriptions.  In the meantime, if you have a question, please just ask and I will be happy to provide more details.

Thanks for visiting!

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