Attaching a pole barn to a house

[Arcticcat843]

I have a 32x56 pole barn that sits roughly 10 feet from my existing house. What I would like to do is build an addition on to my house attaching it to the pole barn. This addition would fill this space and also add 12 feet off the back of my house. The total length of the attached area would be about 36 feet. I have a floor plan drawn up that I'm pretty happy with and have a pretty good idea how I would attach the roof and I don't forsee any huge issues with that. My huge unknown is the foundation. My pole barn posts are set 48 inches deep. The basement floor of the house is also right at about 48 inches below grade. The basement is only about 6 feet tall and 2 feet of it is above grade. I'm not concerned with the added basement space and would even be ok with just a crawl space in the new addition area however I assume I would still have to dig down deeper near the post for a footing anyways. Has anyone ever done this? Is it safe to dig out all the dirt on the ouside of the posts? Is it even possible or legal to attach a pole barn to a stick built house?

Oviously I will have to talk to my building inspector about this at some point but I'd like to have a clear plan put together before I talk to him. They seem to be able to sense weakness and uncertainty and charge you more. Honestly I'm 99% sure I will hire someone to pour or block up the foundation also because I have very little experience with this but I'd like to know if it's ever been done or able to be done before I waste someone's time.

 

[benjamintmiller]

There shouldn't be any code-related issues connecting a pole barn and house, as long as both are below the frost line. The pole barn isn't all that different than a deck.

If you want to stick frame your addition, you will need a foundation down below your frost line, with footings and foundation walls. Around here, the going rate for a foundation without basement is about $45 / lineal foot. I think it would be safe to dig on one side of a few poles, because the rest of the building will hold it in place.

Many towns have ordinances that require accessory buildings be a certain distance from the main structure, usually for fire reasons. You may run into trouble with such a large addition from this, but a smaller breezeway might be approved.

I would talk to your building inspector now, not later. Every one I've ever met has been helpful, and if you ask lots of questions before you apply for a permit you know it will be approved. The cities around here charge based on the dollar value of the addition, not because they sense weakness.

Good luck with your project!

 

[Captain Spaulding]

A few things to be aware of: Your insurance company may not care for the connection. There may be unexpected tax implications. There may be code issues as well.

While many code officials and insurance people will give a lot of slack on a detached building, making it part of a living space might cause them some heartburn.

 

[Arcticcat843]

Well you guys have made me feel a little better about my ideas. I am aware of some of the other issues just wasnt sure about the foundation. In my township a garage is allowed to be attached but there has to be a fire barrier between the two structures. Both sides of the wall has to have 5/8 fire rated drywall, any doors have to be 45 min fire rated and steel and any penetration to the wall has to be sealed with fire caulk.
There are also several other issues I didn't mention but I think I have a plan for all of them at this point. I have electric service (underground) and cable that both enter from this wall of my house so they will have to be changed. My well piping also enters the house underground in the very front corner of the wall so that will have to be worked around. On top of these issues, I also have underground electric ran to the barn and another out building, under ground water running to the barn, and also underground gas line from the house to the barn all in this 10 foot space. The good thing is I installed everything I just listed except for the well so I have a very good idea of the locations and what's going to be involved in moving everything.

The issue with a smaller breezeway is that it doesn't give me the additional sq footage of living area that I desperately need. The main goal is to gain interior space, the attaching of the pole is kinda just a side effect and added bonus. With this space I will be able to add another larger master bedroom, master bath, walk in closet, and a laundry room to the main floor of my house.

I will have to look into the insurance aspect as I hadn't even thought about that.

I guess my next step should be to call the township and see if I can set up a meeting with the inspector. They are not overly friendly that's for sure. I did mention trying to talk to a inspector about this when I was in there office before and they told me I had to apply for the permit before I could talk to him. Which I assumed was about the money so I offered to pay an inspection fee just to be able to meet with him which they still wouldn't let me. From my expericance dealing with him before I'm 99% sure he is going to tell me that basically I do whatever I want as long as I have a engineered plan. I get the impression that he really doenst know so uses that to save himself. I went through the same thing with the truss system in the barn. The barn has a mixture of scissor trusses and attic trusses along with a 8 foot section that's open all the way to the top cord. He made me get a engineered drawing for this which was not cheap. Then I made a appointment for a final inspection to which he never showed up for. I called him and he said he would stop by at some point in the next week and do it because he got busy. Then one day I came home and had a final approval sticker on the door and he never even looked at the truss plans I paid extra for. Anyways I'll try to post back with a update after I talk to him

 

[johnnyradiant]

Just because you could build up to the barn I'd still be left with a little something in the back of my mind about disturbing the soil around the poles. If it were me I'd seek out at least a cheap opinion from an expert as to whether it was a concern to pursue or not.

 

[matt_i]

I believe you will probably be required to build a firewall between the two. More or less two layers of Type X drywall, taped & filled. All the way up to the peak of the roof.

It will impact your insurance due to the connection and potential that a fire could cross via the roofline. My neighbor's detached shop burned down last month, if it was attached he would have probably lost everything.

There could be some issues with having different foundations for the two parts that could have different Z-heights at various times of the year. I would think of compliance when building, using something like peel + stick ice & water shield flashing on all of the "joints" between the three parts seems like something that could withstand some small relative movements and be OK season after season.

 

[6768rogues]

Most codes limit wood framed construction to 6000 square feet without dividing the space with real fire walls or sprinklering the whole place. Unless you have a really big house, adding that building to your house will not take you above that threshold.
Another concern is a wall that will retard the spread of fire or smoke from the storage building to the residential space. You have to find out what fire resistance rating your code requires to separate the two uses and be prepared to build an adequate wall with fire rated doors in any openings. Technically it is not called a fire wall, it is probably called a fire barrier, fire separation or simply a wall with a fire resistance rating. Different codes use different words, but fire wall is fairly universal and you are not constructing a fire wall.
Wallboard does not have a fire rating, type X wallboard is a component in some fire rated wall systems. You need something like UL wall system U465. Google that and take a look. That is for steel studs but there are similar systems for wood studs. That is what your building department will be looking for, you tell them what system you are using and they inspect it to the specs in the system. The system has been tested and will work if built properly. Simply throwing on type X wallboard without following a system gives you nothing but an expensive wall.
Even if the pole barn might move, you can use construction joints that will allow for differential movement between the house and the pole barn.
All things considered, it should not be a big deal to do it legally.

 

[matt_i]

This .pdf has a number of illustrations of fire-rated wall constructions...I think you could improve it even more by using Type C drywall which is even more flame resistant than Type X and not a lot more expensive.

https://www.certainteed.com/resources/FireRatedWallAssemblies.pdf

its a 1 pager, not too big.