Fiber cement siding over EPS with drainage plane?
![](https://secure.gravatar.com/avatar/3790e7959586c370c596960a5eed2a1f?s=52&d=https%3A%2F%2Fimages.greenbuildingadvisor.com%2Fapp%2Favatars%2F200x200%2Fk.png&r=g)
Location: West Yellowstone, Montana, Zone 7. I thought I had everything planned: (inside to outside): 2×6 walls, R-19 in the cavity, OSB sheathing, building paper, 6″ of EPS outside, 1×4 furring strips and then horizontal cedar siding. All set, except that the report on the availability of cedar siding is “almost impossible.” I checked inventory at Menards, and I would have to go to 5 different states to collect enough for our small house and garage.
Since we will be in a fire area, I’m considering changing to fiber cement siding. If I have to change to something else, I might as well do better on the fire rating. But, everything I can find about installing fiber cement siding shows going right over the Tyvek or building paper and nailing directly into studs. Does anyone have any info about installing over a lot of rigid insulation?
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
![](https://www.greenbuildingadvisor.com/app/themes/greenbuildingadvisor/dist/img/modules/detail-library/thumb1.png)
![](https://www.greenbuildingadvisor.com/app/themes/greenbuildingadvisor/dist/img/modules/detail-library/thumb2.png)
Replies
Deleted
Ken,
The Hardi guide allows both installation over walls with no sheathing, and fastening directly to 7/16" OSB. Those conditions are similar to your situation in both the unsupported spans, and depth of backing for your fastener. My only reservation would be that 1"x3"s tend to split easily.
https://www.structuretech1.com/wp-content/uploads/2012/01/James-Hardie-2001-Instructions.pdf
The type of install you describe is done routinely here in Montreal Quebec. As long as tour fasteners for the 1x4 fur rings are adequate to support the weight of the siding I don’t see any issues.
Thanks. I'm surprised they even mention 1x3's, because everything I have read for any type of siding said to use 1x4's as 1x3's would split! This gives me the info I need.
Ken,
You may find this guide useful - starting at page 11.
https://www.victoria.ca/assets/Departments/Planning~Development/Permits~Inspections/Example~Plans/Illustrated-Guide-R22-Effective-Walls-In-Wood-Frame-Construction.pdf
Funny that you sent this link. I have this document and used it to guide some of my design, but I have not reviewed it in detail recently. Thanks for the reminder. Canadians know something about cold. I also found a reference to attaching fiber cement siding in Alaska's REMOTE manual: http://cchrc.org/media/REMOTE_Manual.pdf on pages 34 and 35. Thanks for the thoughts.