Got a strange question.....

[yankeeredneck]

I am going to be remodeling my father-n-laws farm house that was built in the 1960s, when the county did not have codes. The exterior walls are 2x4-16 on center. Is it feasible to change the exterior walls to 2x6 so I can build a second floor or do we just add on to the existing structure? We do not want to tear down the house and start fresh, just add on. It's either go up or go out.

[Don_P]

You can build a second floor atop a 2x4 wall, the change to 2x6 was for insulation.

[rick91351]

I think I would want to do a very good assessment on the condition and the suitability of the foundation.  If poured properly and has not deteriorated a whole lot would make a huge part in my decision.  '60's' is not that old if poured correctly.  But if it was a couple neighbors getting their heads together mixing a batch of mud.....  Some times that is / was great and sometimes not so much.....  By the way if a foundation is poured properly with today's materials and techniques a foundation and footing should last well over one hundred years.           

[yankeeredneck]

Don---- I know I "can" but in our county I cannot. They require 2x6 on all new construction----already asked the building inspector. I asked why not 2x4 since IRC says yes you can----he just looked at me with a blank face, as if he never heard of it. This makes me wonder if I can truly do this due to the IRC codes and if I can prove with the help of an engineer, that it can be done.

The foundation was professionally done back then. I am not worried about the foundation---just wish it was 10ft vs 8ft.

Off to study those codes some more....

[rick91351]

Don---- I know I "can" but in our county I cannot. They require 2x6 on all new construction----already asked the building inspector. I asked why not 2x4 since IRC says yes you can----he just looked at me with a blank face, as if he never heard of it. This makes me wonder if I can truly do this due to the IRC codes and if I can prove with the help of an engineer, that it can be done.

The foundation was professionally done back then. I am not worried about the foundation---just wish it was 10ft vs 8ft.

Off to study those codes some more....

In another county than where we live now.  We were looking at adding a second story.  They would not allow it without six inch foundation walls.  Our basement was four inch in most places.  So pretty well said no to anything we wanted to do.  However in town it did not seem to matter...

One thing we found after Idaho took Federal monies for energy conservation you play by different rules.  Just because the code book says - does not mean necessarily that it is code.     

[MountainDon]

The insistence on 2x6 for new work might be because the local folks are thinking that is the only way to get the required R-value of insulation. That can be done with 2x4 walls by using foam on the exterior or spray in foam in the stud bays.   

Ask them to show you where it says you need 2x6 walls.

For reference on the insulation
http://publicecodes.cyberregs.com/st/nc/st/b4v02/st_nc_st_b4v02_11_sec001.htm

[Don_P]

Building on top of existing construction does not mean you need to switch out the existing construction. It is "grandfathered". As long as you are not tearing those walls out and as long as they are structurally capable of supporting an additional story then they are what they are. It is within his authority to ask that you have an engineer certify that the existing construction is capable of supporting the additional loads.

If you completely remove a wall and replace it he can require that it be replaced with one that meets current code. Structurally a 2x4 will meet current code for most situations. As Mt Don points out you can meet code insulation requirements using a 2x4 wall. If you don't open up the wall cavity he cannot require that the insulation level change in the existing portion of the building. If you do open the wall and have access to the insulation I can see room for saying he can ask for current levels of insulation, if they can be fitted into the existing framing. Although at that point I would go ahead and install foam to get to modern insulation levels, he cannot require more than can be achieved in the existing framing using typical insulation, fiberglass. You can appeal his interpretation first locally and then at the state level.

[yankeeredneck]

Thank you guys...... all this help me greatly. The house has jacks in the basement holding the main floor. I should be able to put a LVL in to carry the load and then trusses for the second floor, as long as the engineer signs off on it. I can post pics this weekend to give you guys more of a visual of what I am dealing with. Although this is not a build from scratch house, it was originally built that way and I just want to add on to an already great family farm home.

[flyingvan]

Could you lift up the original house as the second story and do the new build (with 2x6's) underneath it then set it back down?  That's done not too infrequently around here and the residents continue to live in their house as work progresses

[yankeeredneck]

Sorry for the delay in getting back......work has had me traveling. I have not been able to get those pictures I promised. I will some time this week. I have gotten news on a few things on the layout the wife and I wanted to do.....basically can't do any of it without total redesign of the first floor layout and basement. But the god news is that I can go out rather than up. I have to redo the front basement wall and seal it as it leaks water occasionally during heavy rains and transplant my favorite pear tree but it is a lot easier than reconstructing the whole house just to add 2 more rooms and a full bath.

[odysseusjg]

Correct me if wrong but I think the code requires a footing for two storey wider than a minimum width one storey footing. I think you would have to confirm your existing footing width.