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Roofing/replaceing roof deck

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Question
Replacing the roof deck. 1story almost flat addition on a 2 story house. Addition was built about 1965. In CT. They used 6" wide pine boards for the decking. Rafters are 2x6's. Rafters just miss 16"OC. I will be using plywood for the new roof deck.
Can i nail a 2x6 to the side of an exsisting 2x6 to give me something to nail the plywood into? In other words, i would double the width of a 2x6 and make the roof 16"OC.
Also, the roof is 8' wide by 40'long.8' from roof edge to side of house. I always see new houses with the roof decking laid length wise. Meaning the rows of plywood advance to the peak 4' at a time. 1st row are full sheets, 2nd row starts with a half sheet to stagger the joints. Can i lay my plywood widthwise? One full sheet from edge of roof to wall of house? Then another full sheet next to it, for the length of the roof? Just thinking it woupd he easier then two rows 4' wide and staggering the joints. Thought maybe it did not matter on a small roof.

Answer
Frank,
You should be able to add an additional 2x6 to the existing provided that you span it from support wall to support wall. It should be mechanically-attached to the existing 2x6 utilizing the spacing that is required by the local building department (I'd just call your local building department and ask them what the spacing of the fasteners should be if you are sistering joists - it is likely two rows 12"o.c. staggered).
Regarding the plywood - it is far better to stagger the joints to create a diaphragm method of attachment - it is structurally more sound.
Good luck,
Aaron

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Aaron Nelson

Expertise

All types of questions with regard to roofing, waterproofing and sheet metal. This includes commercial and residential buildings, along with the various aspects of the construction means and methods, ventilation, steep-slope or low-slope, code requirements, installation errors and other such problems

Experience

I started in roofing fabricating and installing sheet metal flashings out of high school for a large commercial contractor. I worked for the same contractor in the office estimating and project managing commercial project for 10 years. I left the construction side of roofing and now work as a roof consultant, which I have been doing for 8-years.

Organizations
RCI, Inc.

Education/Credentials
I am a Registered Roof Consultant (RRC) and a Registered Roof Observer (RRO) through RCI, Inc. RCI is a international group of building envelope professionals. I am an approved instructor for RCI educational programs.

Past/Present Clients
We have worked with many local school districts, insurance companies, HOA's, building management companies, and we have a national client with buildings located throughout the US.

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