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Brian, Architect
Category: Home Improvement
Satisfied Customers: 3123
Experience:  Licensed Architect- 17 years, L.E.E.D. AP
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Feasibility of Use for 2nd Floor Attics

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I'm trying to find out if it's possibly to easily extend our 2nd floor living space into some existing attics above our garage, FR and DR. I will attach a zip file that contain most of the information needed to answer this question. Any help of suggestions would be appreciated. Thank you! By the way, I prefer not to use the Chat feature.


Attachment: 2013-07-28_162837_overhead_revised.pdf

Attachment: 2013-07-28_162854_2nd_floor.pdf

Attachment: 2013-07-28_162909_1st_floor.pdf

Attachment: 2013-07-28_163003_rough_layouts_2013-jul26.xlsx


In the attached zip file, here's an explanation of the file contents:


* Overhead_Revised.pdf shows the layout of our roofs, along with the rafter sizes for each floor of 2nd floor attics. 


* 2nd_Floor.pdf shows our current 2nd floor layout without any changes.


* 1st_Floor.pdf shows roughly what our 1st floor looks like, with the exception that the kitchen has two entrance ways instead of one larger one and the kitchen layout was an old design option.


* Rough_Layouts_2013-JUL26.xls contains several tabs that will help you understand room dimensions and support walls.

Hi, my name is XXXXX XXXXX I will be helping you today.

Anything is possible and I'm sure you can do it; I will just need to see some photos of the existing structure to see how easy or hard it will be. You can upload them to this thread by using the paperclip button.

Without seeing anything, I do know that you will have to increase the thickness of the garage ceiling drywall to 5/8-inch. If there is currently no drywall on the garage ceiling, 5/8-inch, type "x" drywall will need to be installed and any penetrations would have to be sealed to maintain the fire barrier.

If you are satisfied with this answer please leave me a positive rating at your convenience.
Initially the attachments didn't show up for some reason but then they did after my first response. After reviewing them, the 2x members are not able to support a new floor. They are basically only strong enough to hold the weight of attic storage. These existing ceiling joists would have to be replaced or sistered with 2x10's.

I would also recommend having a structural engineer do some actual calculations to verify that you don't need any additional beams and that existing headers are large enough. Especially if you live in an area with winter snow. Snow adds new drift loads to the areas where new walls meet existing roofs and these new loads need to be accounted for.
Customer: replied 3 years ago.

Hi, Brian! When you referred to the 2x members above, were you referring to just the 2"x6" joists or both the 2"x6" and 2"x8" joists above the garage? Also, the garage ceiling does have 5/8" thick drywall. We do live in a cold climate that gets a lot of snow. Does it make sense to create the drawings we want and submit to our village, and then let their structural engineer tell us what we need to do for free?

Hi Dave,
Any ceiling joists that will become new second floor joists need to be larger than 2x6 or 2x8.

Codes determine that certain living spaces need to carry heavy loads depending on the room. Bedrooms are pretty high since their is a chance of a waterbed being placed in there. 2x10's at 16 inches on center typically cover these loads, as long as the spans do not get too large.

5/8-inch drywall on the garage ceiling will save you one step. The cold, snow climate will definitely add extra loads due to snow drift and yes you should have a structural engineer look at this, whether it is a local one or one through the village. If the village has one for free....take advantage of it.

Like I said earlier, anything can be done; you can pretty much design anything and it can be built. It's just the more complicated the framing gets, and the added structural engineering and the potential for larger beams can add cost to the project.
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