Helpful? 0

What is the recommended or code requirement for finishing the bottom edge of exterior rigid insulation?

On the exterior of my home I plan on using 1/2" OSB, 1" rigid insulation, with 1x4 furring strips (and insect screen) creating a drainage plain, covered by fiber cement siding. I wonder if the fire code deals with this specifically or not? (Leaving the bottom edge and the drainage plain open to the bottom side.)

You have really the best articles dealing with exterior insulation and drainage plains, but I don't recall seeing if leaving the bottom edge exposed is OK or if it is better to put a drip rail under it, or what some other solution might be?



Asked by Ron Lay
Posted Tue, 01/14/2014 - 17:23
Edited Wed, 01/15/2014 - 08:21


3 Answers

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Helpful? -1

Check out search OSB rot.

Then think about using Zip R-sheathing, with 1" of foam safely tucked inside your wall. Seal the rest of your frame properly, flash your windows and doors properly and you will have a great build IMO.

Much less to deal with than your posted specs. IMO.

Try it, Mikey likes it, and now aj does too

Zip R-sheathing.jpg
Answered by aj builder, Upstate NY Zone 6a
Posted Tue, 01/14/2014 - 17:33

Helpful? 1

Here is a link to a video that shows you how to trim the exposed bottom edge of the rigid foam with metal flashing: How to Install Rigid Foam Insulation Outside a House.

Answered by Martin Holladay, GBA Advisor
Posted Tue, 01/14/2014 - 17:34

Helpful? -1

If not sheathed choose Zip R-sheathing. You will eliminate many labor steps along with whatever mistakes the trades will build in.

Answered by aj builder, Upstate NY Zone 6a
Posted Tue, 01/14/2014 - 17:54

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