0 Helpful?

Is sheathing necessary on a chimney chase?

I have framed a chimney chase of considerable height over my garage.

I was planning on nailing board and batten siding (1x12 Eastern White Pine with 3" battens) directly to the frame.

The structure is extremely stout, so I don't need sheathing for racking resistance; can you think of any compelling reason for me to add it?

The flashing will naturally run up behind the siding. Should I refrain from nailing through the flashing?

Asked by Ben C.
Posted Jul 12, 2018 2:02 PM ET

Tags:

5 Answers

Select your preferred way to display the comments and click "Save settings" to activate your changes.
1.

Sketch.

side view_zpsqc7w6ddj.jpg
Answered by Ben C.
Posted Jul 12, 2018 2:05 PM ET

2.

Ben,
The main reason to include sheathing and a WRB (integrated with the flashing, of course) is to prevent water entry.

Answered by Martin Holladay
Posted Jul 12, 2018 2:09 PM ET

3.

The base of the frame is at least 5.5 inches deep on all sides. Do you think enough water could penetrate the siding to cause a problem? Would a little bit of water on the frame present much of a problem? I could always paint the frame with pine tar.

Answered by Ben C.
Posted Jul 12, 2018 2:35 PM ET

4.

Ben,
Almost all sidings leak. Certainly, board and batten siding leaks when there is wind-driven rain. During a rain event, your approach risks having water get behind the flashing. The water could easily show up on your ceiling.

Answered by Martin Holladay
Posted Jul 12, 2018 2:47 PM ET

5.

You've convinced me to use use 30 lb. felt behind the board and batten. I'll run it down over the top of the flashing. I'll follow up here to let you know how it performs. Thanks again, Martin!

Answered by Ben C.
Posted Jul 12, 2018 3:01 PM ET

Other Questions in General questions

Basement walls: Encapsulate with plastic sheet, tied to interior French drain?

In Green building techniques | Asked by Corry Daus | Jul 18, 18

Ventilation baffles over lean-to?

In Energy efficiency and durability | Asked by Dylan Hillman | Jul 20, 18

Help with air-source heat pump sizing

In General questions | Asked by Lyell Slade | Jul 4, 18

Triple glazing or high-end double glazing?

In Energy efficiency and durability | Asked by User-7088022 | Jun 12, 18
Register for a free account and join the conversation


Get a free account and join the conversation!
Become a GBA PRO!