2X6 OR 2X8

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Posted by: from Welland
8/20/2012 at 9:21:49 PM

I'm building an addition on my house and the walls are 2 x 6 sixteen inch centers. I want to build a flat roof on top of my addition for a balcony.

What size floor joists should I use?

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Date/Time8/20/2012 at 10:12:45 PM

Hi Joseph,

Before you undertake this renovation. Please take the time to consult with a structural engineer. There are many factors to consider. Span, snow loads drainage etc..... it is in your best interest to have proper drawings and permits in place before you start..

I hope that this helpful.



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John from Accu-Struct in Belleville
Date/Time8/20/2012 at 10:21:11 PM

I agree with Neil your best bet is to consult with your local building department or an engineer first but even if they say 2x8 is good go with a 2x10 always go a shot above minimum requirements if its worth doing its worth doing right.

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Date/Time8/21/2012 at 8:28:44 AM

Hi there,

What size to use it depends on span of Your structure.

if You want to eliminate future headache take structural engineer.


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David from Chetco Homes in Fort Erie
Date/Time8/22/2012 at 10:04:26 AM

Depends on the span, 8" will span 12 ' on 16' centers.

Good luck


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Joseph in Welland
Date/Time8/22/2012 at 8:29:45 PM

i already framed the walls so the roof will be a shed roof with a 10 foot span including the overhang and i want to build a deck on top so i can sit up there a few people and some lawn chairs.

I would use 2x10 but then my overhang will be to big to finish the facia aluminum which should be 2x6 not 2x10 ?

So should i use 2x6 or 2x10?

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Joseph in Welland
Date/Time8/22/2012 at 8:32:43 PM

CORRECTION, I ment to say 2x6 or 2x8.

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John from Accu-Struct in Belleville
Date/Time8/26/2012 at 10:12:29 PM

If the span is only 10' including the overrhang you can use a 2x8 my question to you is what are you using for roofing product? Traffic ontop of the roof deck can cause leaks what type of area is beneath this roof is it a living space or garage? And how will you be accessing this deck area?

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Joseph in Welland
Date/Time8/27/2012 at 7:16:53 PM

The room below the roof is a mud/laundry room, the roof will be either a shed roof with shingles or a flat roof and im going to build a presure treated deck on top of the roof so i dont damage the roof membrane or the shingles witch ever one i use my addition is atached to my existing house witch is aone and a half storey so the second floor window will be removed and im adding a exterior door in its place for me to access the roof (deck) of my adition.

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Robert from Electrilight Ltd. in Oakville
Date/Time9/1/2012 at 4:31:45 PM

Honestly, If you have to ask for dimensions of materials, you should be hiring someone to come in and look over the entire project and get it done safely and by building code. Guesswork in building structures can be fatal.

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