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Going up or Out add on


starwalls's Avatar
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NH

04-07-11, 05:09 AM   #1  
Going up or Out add on

I understand going up may cost less, but can you use most of the roofing like the wood? How would you know if the bottom that was built can hold what you put on it? I have a 24X42 ranch
they used 2X8X12 as joist... After I have the framing and roof on I would be doing the rest myself, plumbing electrical ect...Or should I just go out with a half cellar???

 
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Wirepuller38's Avatar
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04-07-11, 05:50 AM   #2  
Up vs. Out

What kind of lumber was used for your ceiling joists? If you go up, your ceiling joists will become the floor joists for the second story addition unless you replace with bigger lumber.

 
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04-07-11, 09:06 AM   #3  
2x8 joists with 16 on center will not meet building code for a 2 story house. They barely meet it for a one story for those that do not want floor bounce. The added load of a second floor will require complete new main floor structural engineering, or the second floor would have to have load points separate from the main house structure with it's own I beam structural support system engineered going into separate ground footings is my guess. It won't be cheap, and you will also need to pay for a new roof/materials. Nobody would spend time trying to salvage anything from the old one. I think that there would need to be good non financial reasons that you would want to add a second floor to your ranch house rather than just sell and move to one. Usually those reasons are around the specific lot for instance. Something on a lake or a lot with a view you would never easily find again.

 
starwalls's Avatar
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04-07-11, 11:40 AM   #4  
Why or how could they have built this useing 2x8 joist?
I understand what you are saying cause I asked the same thing when they were building. I was told as long as they use t/g ply there was no problem. In any case go out??? Is what your saying

 
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04-07-11, 11:58 AM   #5  
Hopefully, what you have built according to the local codes at that time. Codes are continually changing based on performance and problems. If you do not change that part of a structure, you can USUALLY rely on the previous permit and certificate of occupancy (COA).

If you add on vertically and change the structure, you them fall under the current code and must comply with it. You will need professional guidance to sort out things before construction and facing an inspection. Every area may have unique standards

If you add on horizontally without affecting the existing structure, you MAY only have to deal with the modern code in effect at that time for just that portion. Again, you need a professional for guidance.

Obviously, you cannot afford to not have a permit for an addition is you ever expect to sell the property without discounting the price.

 
equinox's Avatar
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04-08-11, 05:49 AM   #6  
Going out is probably your most cost effective option especially if you only bring down the foundation walls to the frost line requirements rather than dig and pour additonal basement space under the addition and then open it up to the what is already there. More than likely you will be able to maintain the 2x8 floor structure with this addition also which should make it fairly easy to level the new with the old floor. Going out will require only basic design and strutural drawings without complicated engineering, a survey and of course a site plan to ensure that it meets code and building regulations for you to obtain a bulding permit depending on where it will attach to your house and the current structure. 2x8 joists on 16 have been used as code minimum standard for along time with single storey houses. Years ago that was plenty when 2 x really meant 2 x. Today it doesn't of course but they still do provide the minimum load/foot structural requirements for most areas with the possible exception of homes located in heavy snow belt areas for example. Builders often spend to minimum codes on what buyers don't see and use some of the savings to help market their property with trendy design features. Personally I would rather have a 2x12 or equivilent floor joist structure and leave out the high end granite if both together didn't fit my budget, but that's just me.

 
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04-08-11, 01:26 PM   #7  
Your floor joists meet minimum codes today. The first chart is for sleeping rooms, 30#, the second chart for standard house floors, 40#, depends on lumber species and grade, not placement of floor; Chapter 5 - Floors

Rafters are affected by snow load, not floor spans, possibly switched? Been there, done that….

Your studs may be a problem. 2x4 x 16”o.c. will carry an added second floor, ceiling and roof if the house span is under 32’; Chapter 6 - Wall Construction

Your biggest problem is a two story house requires an 8” concrete stem wall and wider footing rather than the (probably) existing 6” for a one story structure. Chapter 4 - Foundations

Chapter 4 - Foundations

Unless your local B.D. will pass your existing footing and foundation wall for the added second floor, out would be better.

Gary

 
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