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</o:shapelayout></xml><![endif]--></head><body lang=EN-CA link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>We have done a lot of infill between framing with eps for walls (2x4 fingerjoint @ 24” o.c. work well with precut foam but I still have it undercut. Rafters are more difficult and time consuming – even assuming they are installed relatively parallel there will be significant variation so in our experience precut accuracy is better sacrificed for on-site expediency. We have both a handheld and table mounted foam saw and cut panels roughly ½” undersize in 4’ sections. Quickly spot adhered (foam adhesive) to the sheathing above and locked with wedges (foam) – aiming for roughly a ¼” gap all round. Subsequently the gap is shot with expanding foam (jamming the gun nozzle to the sheathing in the ¼” gap allowing the foam to expand out and fill the gaps). We keep a few guns going with both foam structural adhesive(low expansion) and expanding foam filler. Finally everything is trimmed and air sealed with vb tape (edge to edge and edge to wood) note – tape will not stick to freshly manufactured eps board – needs to be unwrapped and left for a few days. The interior infill should be a low density type 1 eps and the outboard insulation needs to be of sufficient thickness to maintain interior drying. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Ceiling electrical lines can be scooped in with curved hot knife blades or with a laminate router and subsequently foam filled<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>This produces a pretty stiff assembly and sealing with vb tape can be pretty effective but it is structure so still subject to movement that can create air paths so the ceiling finish should also be well detailed as an air barrier to provide some redundancy.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I think it would be less work (cost) and more effective to sheathe the roof, laminate the thickness of foam on and laminate on another layer of sheathing – leaving the inside structure open for wiring and nice and dry.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span lang=EN-US style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span lang=EN-US style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Greenbuilding [mailto:greenbuilding-bounces@lists.bioenergylists.org] <b>On Behalf Of </b>Eli Talking<br><b>Sent:</b> January-03-13 8:04 AM<br><b>To:</b> jfstraube@uwaterloo.ca; archilogic@chaffyahoo.ca; Green Building<br><b>Subject:</b> [Greenbuilding] Foam installed between framing during framing<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><div><div><p class=MsoNormal><span style='font-size:14.0pt;color:black'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:13.5pt;color:black'>I am wondering if it would be reasonable to install accurately precut eps foam between joist, rafters, or top chord of truss during the framing to achieve a cheap relatively tight installation when compared to fiberglass with the air seal being achieve outside the framing with continuous 6” eps foam managed for air tightness. More detailed description is below. </span><span style='font-size:14.0pt;color:black'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:14.0pt;color:black'> <o:p></o:p></span></p></div><div><p class=MsoNormal><em><span style='font-size:14.0pt;color:black'>From: John Straube </span></em><span style='font-size:14.0pt;color:black'><o:p></o:p></span></p></div><div><p class=MsoNormal><em><span style='font-size:14.0pt;color:black'>Sent: Wednesday, November 28, 2012 1:13 PM </span></em><span style='font-size:14.0pt;color:black'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:14.0pt;color:black'> <o:p></o:p></span></p></div><div><p class=MsoNormal><em><span style='font-size:14.0pt;color:black'>Experience has taught those who have built a few of these externally-insulated buildings that they can be easier to build too. This means one has to learn how to handle the remaining challenges</span></em><span style='font-size:14.0pt;color:black'><o:p></o:p></span></p></div><div><p class=MsoNormal><em><span style='font-size:14.0pt;color:black'>1. how to find low cost long screws that screw in quickly and easily</span></em><span style='font-size:14.0pt;color:black'><o:p></o:p></span></p></div><div><p class=MsoNormal><em><span style='font-size:14.0pt;color:black'>2. the furring needed to allow for easy cladding fastening</span></em><span style='font-size:14.0pt;color:black'><o:p></o:p></span></p></div><div><p class=MsoNormal><em><span style='font-size:14.0pt;color:black'>3. the details at window and door openings required to mee</span></em><span style='font-size:14.0pt;color:black'><o:p></o:p></span></p></div><div><p class=MsoNormal><em><span style='font-size:14.0pt;color:black'>Point 3 is still evolving and improving.</span></em><span style='font-size:14.0pt;color:black'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:14.0pt;color:black'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:14.0pt;color:black'>My comments:<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:14.0pt;color:black'>I am designing a house mounting eps on exterior of framing. I found a source of eps that is a lower price than fiberglass/R. By making it on the outside, I avoid the conflict with wires and plumbing commonly installed in the framing and achieve continuity. Also, the framing is inside the thermal envelope and therefore near the conditioned temp. I am addressing the three issues John brought up. <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:14.0pt;color:black'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:14.0pt;color:black'>I found a source of long screws. <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:14.0pt;color:black'><a href="http://www.loghomestore.com/1748-headloc-panel-fasteners-9-to-18-inch.php">http://www.loghomestore.com/1748-headloc-panel-fasteners-9-to-18-inch.php</a><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:13.5pt;color:black'>Prices seem reasonable. Far less than GKR screws that I love. However, the screws are a significant cost. My original intent was to mount 12”eps over the roof sheathing. However, using a spacing of 2’oc on furring strips that are also at 2’oc, it results in 4 screws/4sf, or 1 screw/sf. On the walls, my 6”foam is setting on the foundation with no significant loading except for wind suction. My site is windy. For this I need am planning a 9.5” screw at </span><span style='font-size:14.0pt;color:black'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:13.5pt;color:black'>$.50/screw in bulk. However, the thicker roof would need 16” screw for $1.22/screw. That is a significant sf upcharge. The 12”eps is only $1.56/sf. I am aspiring to keeping the cost down to create more access for high performance. As a result of this cost, I made the recommendation that we insulate the ceiling of continuous 4” eps mounted below cheap plane jane truss to achieve the continuous thick air barrier with cellulose toped off to achieve higher R value. I believe this is the most cost affective way to top off the thermal envelope. However, my clients want to develop the attic. Therefore, we are back to wrapping the insulation above the roof sheathing. However, because of the cost of the fasteners, I am looking to skin it with only 6” foam to achieve thick air barrier and put some insulation in between attic truss top chord to increase the R value. Fiberglass would be the easiest. Because of the above roof eps, it probably would be ok, even though it is air pervious. I would follow <a href="http://www.buildingscience.com">www.buildingscience.com</a> ‘s recommendation for proportion of air pervious to non air pervious to insure inner most foam temp remains above dew point in winter with 50% relative humidity in house. </span><span style='font-size:14.0pt;color:black'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:14.0pt;color:black'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:13.5pt;color:black'>However, I am wondering if you could precisely cut eps foam to the exact 22.5” spacing between truss top chord mounted at 24”oc. I see this as being installed during the framing with a friction fit. Since the top 6” insulation achieves the air barrier requirement, I would not think additional sealing would be needed. Even without sealing, the nature of eps would be much tighter than fiberglass. It also turns out it is less expensive. This could also be done at the band joist. Installing during the framing allows the foam to be used as a spacer to create a tight fit that would be difficult to achieve after framing. However, I have not seen it done this way. Therefore, what are the risk that I am not seeing? Or is this a reasonable idea to increase R value at a low cost?</span><span style='font-size:14.0pt;color:black'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:14.0pt;color:black'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:13.5pt;color:black'>List input is always appreciated. </span><span style='font-size:14.0pt;color:black'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:14.0pt;color:black'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:13.5pt;color:black'>Eli</span><span style='font-size:14.0pt;color:black'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:13.5pt;color:black'><a href="http://www.conservationarchitect.net">www.conservationarchitect.net</a> </span><span style='font-size:14.0pt;color:black'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:14.0pt;color:black'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:14.0pt;color:black'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:14.0pt;color:black'> <o:p></o:p></span></p></div></div></div></div></body></html>