# wanting to change roof line (concrete load advice)



## bluebird5 (Dec 13, 2010)

This is a personal project of mine and not a paid job, but I am looking for some ideas. I also realize that this my require the advise of a structrual engineer, but its raining here and I just want to get you guys take on the situation and see if ya'll think im nuts or not.

I am thinking of changing my roofline. There is a room added onto my house sitting on a slab. The slab is 6 inches thick but does not have a footer.

It is 6 inches of concrete sitting on top of the soil. The soil is not sandy. I live in nashville tn so the winters are cold but not extreem like the northeast. 

Right now the roof is a 3:12 but I am looking to change it to an 8:12. So the slab will be bearing more load on the edge. This roof will be sitting atop a 2x4 wall. 

I am wondering if the slab will start breaking on the edge or if I have nothing to worry about because after all... it is conctete and concrete is strong. Here are some pics of what I got right now

If you could picture the roof going from the front all the way to the back and do away with the compound pitch


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## CookeCarpentry (Feb 26, 2009)

What's code say in your area about slab on grade and footers?

You have to pull a permit (I assume) to alter the roof framing, inspector might question the footer (or lack thereof) and make you fix it.

If it was my house, regardless of if it was being inspected or not, I would want a solid footer/foundation under that room.


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## bluebird5 (Dec 13, 2010)

well th room was already on here when i moved in. Its not my doing (the no footer thing). I think what i showed is the thinnest place. So are you proposing I dig under the slab on the edges down to the frostline and pour it up to the slab?


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## Warren (Feb 19, 2005)

The addition is grandfathered in according to code, but if you add to it or alter it in any way, you are responsible to bring it to code. I am sure there are ways to underpin what is there. Not sure how cost effective that will be though. Why are you going with an 8/12 pitch on the roof? I think I would keep the one side, it looks like a 5/12, and continue it farther and then 5/12 it back down to the addition. Will save a few bucks that way.


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## bluebird5 (Dec 13, 2010)

ok warren are you saying to leave the ridge were it is and leave the front half of the rafers on and go from that ridge go back down to the addition? or are you saying to do what i had originally talked about and take the whole roof off and center the ridge but go with a 5:12 instead of an 8 to reduce the load?


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## CookeCarpentry (Feb 26, 2009)

bluebird5 said:


> well th room was already on here when i moved in. Its not my doing (the no footer thing). I think what i showed is the thinnest place. So are you proposing I dig under the slab on the edges down to the frostline and pour it up to the slab?


You might be able to get away with a footer on each corner, then a post up to a structural header (in the 2x4 wall) that the rafters would then set on.

At least then you are only messing with 2 areas, maybe 16" diameter footers, rather than the whole bearing wall.

Just throwing out ideas.


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## AustinDB (Sep 11, 2006)

if you raise the roofline too much you may need to increase the height of the chimney...even if you don't 'use' it, it has to be 2' above roofline (2'w/i10')


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## JT Wood (Dec 17, 2007)

CookeCarpentry said:


> You might be able to get away with a footer on each corner, then a post up to a structural header (in the 2x4 wall) that the rafters would then set on.
> 
> At least then you are only messing with 2 areas, maybe 16" diameter footers, rather than the whole bearing wall.
> 
> Just throwing out ideas.



That is a good idea.:thumbsup:

Speaking of throwing out ideas,


What about the beam on top of the wall? to avoid disturbing the drywall


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## bluebird5 (Dec 13, 2010)

72chevy4x4 said:


> if you raise the roofline too much you may need to increase the height of the chimney...even if you don't 'use' it, it has to be 2' above roofline (2'w/i10')


I will either raise the chimney or do a hip roof


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## CookeCarpentry (Feb 26, 2009)

I have no idea where to get a dumpster....


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## greg24k (May 19, 2007)

Bluebird...Beware!!! Don't Do It!!!


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## Joe Carola (Jun 15, 2004)

bluebird5 said:


> This is a personal project of mine and not a paid job, but I am looking for some ideas. I also realize that this my require the advise of a structrual engineer, but its raining here and I just want to get you guys take on the situation and see if ya'll think im nuts or not.
> 
> I am thinking of changing my roofline. There is a room added onto my house sitting on a slab. The slab is 6 inches thick but does not have a footer.
> 
> ...


Can you take a picture of the left and right side of the house? The back of the hows looks like it shows three jogs in it.


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## bluebird5 (Dec 13, 2010)

the other end of the house has a carport on it, and its not good either. the house has 3 double roof pitches and it leaks. the only issue I have is the no footer thing with th slab. by changing to an 8/12 am I really putting that much more load on the slab?


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