October 23, 2015

Question of the Week – 10/23/2015 – Post-Fire Rebuild

You may think of 475 as a place you can call when you’re working out a detail, a website to visit to read technical discussions, or if you live in Brooklyn, a place to go to ask a question.  But we also try to provide the best service on the ground, which is why we have Product Consultants in many areas who are constantly out there looking to bring solutions to your challenges.  Oliver often makes trips to jobsites to catch up with ongoing projects, and he never leaves without hearing some questions and providing some recommendations.  This week’s Question of the Week comes from a team in Vermont who are working on a post-fire rebuild, with some tricky details.


The question:

“Fortuitous meeting you the other day while you were in town.  Glad that you were able to stop by the barn and see where it all started.  Happy to chat later this week about using the Contega and your thoughts on laminating the Solitex to the rigid Knauf insulation.  Also wanted to mention that from an air barrier perspective we would be doing the intello on the inside of the OWJs and then the plan is to do lime plaster gypsum board on top of that.”


The background:

This team is using INTELLO Plus at the roof interior for airtightness and vapor control.

Things get more interesting at the top. They have the roof already installed over open web joists. Their idea is to add a Knauf-SOLITEX lamination that gets pushed up against the inside of the flanges so that they get a vented space between the SOLITEX and roof.  While brainstorming, we suggested using CONTEGA HF then fastening with wide flange screws.  A bigger question – we thought – might be how to connect SOLITEX at the ends if it’s not pre-taped in one long piece?   We would assume they want to have 8′ pieces pre-adhered to the SOLITEX.


The answer:

Install the SOLITEX first.  Clamp it with small (1×2) battens on the side, with Contega HF adhering to the rafter and ideally a 2×3 in the center of the joists to make it an inside gutter (see the diagram below).  This can be a precut width of SOLITEX (like at Alex Wilson’s house).  Then you can install insulation against that.  This is an easier application than our suggestion above, and is fully sealed – no untaped seams.


solitex at flat roof






In summary:

If you have a tricky situation that you’ve never encountered before, bring it to us – we might have seen it before and even have a drawing to help explain.



Thanks for reading, keep in touch!

To read the other posts in our Question of the Week series, click here.


**Please note that in republishing our question of the week, we sometimes edit the text of the original question and response in order to provide additional clarity to the issue.**

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