Non-Load Bearing Walls/Studs Becoming Load Bearing!? 1

[kxa]

I inspected and old (100+ yrs) house that at some time in the past had its unfinished attic converted to a living space. A few walls were apparently added which clearly were not structural and the color of the wood is even different. My guess, 30 or so years old. All walls and a few studs were connected directly to the rafters. Now the building department inspector wants them removed. During the inspection, I noticed that these walls and studs appear to be under some stress meaning they are carrying load from the roof. I figure the weight of the added sheet rock to the underside of the roof rafters (1.75"x3.75" @ 24" oc)and the snow,.. have over time pushed the roof framing downward that these walls now carry some load. As such, I don't feel comfortable having these walls and studs removed.

I was just wondering if anybody else ever encountered similar situation and what they did about it.

 

[msquared48]

Well, analyze both conditions and see what the problems are, if any.

I understand why the BO wants to remove the wall, but doing so could cause cosmetic as well as structural problems below. If the attic walls were changes to the original framing, what other changes were made that you do not know about?

I would retreat to the old addage, "if it ain't broke, don't fix it."

Mike McCann, PE, SE (WA)

 

[msquared48]

A couple more things...

It is very common for rafters of that era to be over spanned today, even considering the better material of the time.

You are probably correct of them sagging ant the wall being added, but it was also common attic framing to have two internal walls with the rafters cantilevering over them to a ridge board.

.

Mike McCann, PE, SE (WA)

 

[bigmig]

The same condition happens in new construction. Engineers "ignore" all those rat maze walls running on the interior, but in all reality, if you build the wall tight to a roof system (prefab truss for instance) you can bet that truss will notice. When you try to gap your wall to ceiling detail so that they DON'T engage, builders look at you like you are an idiot.

I was always told that the building roof/floor system acts as a unit, to a point. Once the system loads up enough, the roof realizes that it has to do the work it was originally designed and built for, at which point it starts to behave more like the simplified model we design for.

Getting back to your historic building, msquared48 is right. If the system won't work without the walls, that is something you need to identify. The IEBC is specific on how to address these grey areas. Yes it may be overstressed per today's code, but the fact is has been standing for 109 years is something that many non-engineers are quick to point out. The IEBC addresses this, and many other conditions. In short, if you touch it, you buy it. Many jobs go to great lengths to not alter historic structure for that very reason. You may have to rebuild the entire thing.

Here is the online IEBC Link:

http://publicecodes.cyberregs.com/icod/iebc/2009/

I have never had a building inspector tell me to remove structure. Typically it is the other way around. Keep in mind that the agency he works for is indemnifiable for most of the direction he gives you. Your insurance policy on the other hand is anything but.

 

[JLNJ]

Hey M^2

I heard that old adage recently as, "If it ain't broke, don't break it."

 

[kxa]

Thank you all for your input. Many time I have heard from clients that the building department wants to make sure some areas of the house remain as non-living spaces if they were originally designated as such. This is to prevent people from adding rooms, bathrooms, etc. when can't meet code requirements. Otherwise they have to pay more taxes. Sometimes they as for collar ties to be installed when not needed so that nobody can walk thru attic or finish it.

Anyway, I intend to recommend against removal of the walls. It is just hard to prove by today's standards how these small size rafters spaced at 24" spacing are structurally adequate but yet they have performed well over the years!!