Gambrel Barn. 32x48

[wedge40]

I've always liked the looks of a Gambrel roof on a barn/shed. I know i can the trussed from the places I'm looking at getting quotes from. Both are Amish and will make just about anything.

In the begining I would have the barn just open to the roof. I think they can make the Truss with out a bottom cord and a couple of gussets and cord along the sides.

As time goes and money builds I would like to take part of the barn and build a second floor.

Is this going to be something easy to do after the fact? I know it wont be the same as getting it done up front. But I'd rather do things in stages and get what I really want.

What will be the pro's and con's of doing the barn this way.
With a 27' ceiling I imagine that lighting and heat may be challenge. I do plan on having radient floor heat.

Wedge

 

[scgargoyle]

I just bought plans from Barn Plans - Blueprints, Gambrel Roof, Barns, Homes, Garage Workshops, Dormer Window, Cupola. They have sizes up to 36' wide, and whatever length you like. The building method is to build your four walls and your loft deck, then build the trusses on the loft deck, and stand them up. The trusses are free span, so the entire loft is usable. I'm building mine 28 X 48, and the plans were about $250. I think they're well worth it. If nothing else, you can get a lot of good ideas from their website.

 

[BungeeII]

I'm not a builder, so take this with a grain of salt.

You do not have to put the floor (hay mow) in right now, but you do need to have the beam/support factored into your build up front. You'll eventually need a carrier beam across the middle (cutting your span from 32' to 16'). The floor joists will likely run from the front wall to the rear. So, you'll need properly sized posts and beams along the front and rear walls to support the future load. This will impact your cement pour, as the pads beneath the posts should be sized properly.

 

[charlz]

In the begining I would have the barn just open to the roof. I think they can make the Truss with out a bottom cord and a couple of gussets and cord along the sides.

My shop 20x32 was built in the 70's and the gambrel trusses do have a bottom chord which makes the upstairs ceiling height about 6' 2"... dang inconvenient as I would like to finish that space and use it as an office etc but the ceiling is really low. Sounds like your roof is going to be quite a bit higher than mine but I would pay attention to what the second floor ceiling height would be if you finished it off in the future.

 

[wedge40]

My shop 20x32 was built in the 70's and the gambrel trusses do have a bottom chord which makes the upstairs ceiling height about 6' 2"... dang inconvenient as I would like to finish that space and use it as an office etc but the ceiling is really low. Sounds like your roof is going to be quite a bit higher than mine but I would pay attention to what the second floor ceiling height would be if you finished it off in the future.

Ah.. One of the few advantages of being vertically challenged. I stand a whopping 5'3". The design I've come up with has each cord about the same length. I haven't checked but I think my second story will give me a full 8' celing in about 75% of the space.

Scgargoyle - I'm looking to add the second floor later, and it will only be about 20' of the 48'.


BungeeII - This will be an open floor plan.. No posts in the way on first floor. I'm pretty sure I can get either gluelam or I-Joist to span 32 feet.

Again these are just ideas. I'm really trying not have to take out a home equity loan for a barn.

Wedge

 

[towmotor]

Your trusses will be quite expensive for a 32' span, considering what you'll actually get for your money.

Someone already mentioned the fact that you're going to need a center girder, trusses or no trusses, and I'll echo that sentiment.

That's not to say that you couldn't support a floor (hay mow?) on the bottom chord of such a truss, but as I mentioned in the beginning, it's going to cost you, and furthermore, the resulting trusses will be so danged heavy and clumsy you have to hire a crane to put them up. No question about it.

For my money?
I built a gambrel barn, 26' x 28'; I used a nail laminated (3 2x10's and plywood) center girder, supported by three lally columns.
The second deck is Douglas Fir 2x8's, spaced 12" OC, with 5/8 plywood.

The roof structure is rafters. I have two gable dormers on mine, which makes the roof framing a bit more difficult. You made no mention of anything like that, so it should be easier going.

The steep portion of the roof is simply nailed to a knee wall (about 6'6" high) and the header joists.
That aspect of a gambrel roof is one of the real appealing points to me: you're building triangles on triangles, so as long as your floor structure is adequate to support the knee wall, your roof will be very strong and wind resistant.
Another benefit is the use of smaller pieces of lumber, making it easier for one guy to go it alone, if need be.

I mentioned the the 6'6" knee wall: the height to the ridgeboard is over 11', with usable space 20' wide the entire length of the building, not including the two dormers.
That's how I would do it if I were you.

Just my 2 cents.

 

[Labrat]

I used a double scissor truss wtih a plate and collar tie at the top. It's about 11 foot the the bottem of the collar tie. I also have a 40foot 10inch steel I beam down the center to support the floor without any posts.

 

[wedge40]

Someone already mentioned the fact that you're going to need a center girder, trusses or no trusses, and I'll echo that sentiment.

So I will need a center beam/girder to divide the 32' down to 16'? I have an overhead door in the center of one of the 32' sides. This poses another problem. Aslo I'm hearing that making a clear span, ie completely open 32x48 is impossible?

That's not to say that you couldn't support a floor (hay mow?) on the bottom chord of such a truss, but as I mentioned in the beginning, it's going to cost you, and furthermore, the resulting trusses will be so danged heavy and clumsy you have to hire a crane to put them up. No question about it.

No bottom cord on the roof trusses. See attached.
I have a sample layout I posted here about a week ago.

Thanks for the input so far.

Wedge

 

[GT2]

- I'm looking to add the second floor later, and it will only be about 20' of the 48'.
- This will be an open floor plan.. No posts in the way on first floor. I'm pretty sure I can get either gluelam or I-Joist to span 32 feet.
Wedge

I don't see why this wouldn't work.
However if your going to be putting a lot of weight on it you prolly should use a glue lam at the front and rear of the "second floor"
Use 20' 2x12 or engineered joist for the floor, set on top of the glue lam's.
Under the lam's at each end build a small supporting " wall " out of multiple 2x's or posts.

 

[wedge40]

I don't see why this wouldn't work.
However if your going to be putting a lot of weight on it you prolly should use a glue lam at the front and rear of the "second floor"
Use 20' 2x12 or engineered joist for the floor, set on top of the glue lam's.
Under the lam's at each end build a small supporting " wall " out of multiple 2x's or posts.

Could you sketch this up. I'm not following.
I'm not home otherwise would post a jpg of the plan for the first floor and people could mark it up.

I used a program call Home Designer from Chief Architect which can export to a couple of other formats.

Wedge

 

[charlz]

Ah.. One of the few advantages of being vertically challenged. I stand a whopping 5'3".

I am only 5' 10" myself but the trick is light fixtures etc. I would constantly be banging my head on something.

I have thought about getting a quote to jack the whole roof up and put a knee wall in. Not sure if that is possible or what the cost would be.

 

[civesnedfield]

So I will need a center beam/girder to divide the 32' down to 16'? I have an overhead door in the center of one of the 32' sides. This poses another problem. Aslo I'm hearing that making a clear span, ie completely open 32x48 is impossible?



No bottom cord on the roof trusses. See attached.
I have a sample layout I posted here about a week ago.

Thanks for the input so far.

Wedge

Hate to say this but you are going to have to frame the second floor before you put the rafters up. That is unless the trusses are going all the way to the ground. The reason for this is that the second floor joists also tie the side walls in. The load from the roof has a natural tendency to push the side walls out. So you either have to design some sort of wall tie system or frame the second floor.

 

[Duffster]

ie completely open 32x48 is impossible?

No, nothing is impossible.

You could build the floor using floor trusses.

 

[towmotor]

Well, almost anything can be done, but you're going to dig deep in your pockets the more "imaginative" you get.

You've said you want to put this thing up for as little dough as possible; right?
If that's your desire, then building with conventional methods will be the least expensive way.

You seem to have some compelling objection to vertical supports in your downstairs work area.
Why?
Lots of folks have very work-conducive spaces in spite of the necessary support structure for a second floor.

One possibility that hasn't been mentioned, at least not that I noticed, is the possibility of using a steel frame for your building.
Five steel trusses, placed 12' OC, would get you where you want to go, and you wouldn't need to build your loft right away either, if the trusses include members that will eventualy support your floor. No intrusive support columns to get around.Excavation work might be less too, since, last I checked, you can set those steel trusses on (big) concrete piers.
Maybe a crazy thought on my part, but sometimes the crazy guys get the girl.

That'll be 4 cents please

 

[BungeeII]

I don't believe you can get a clear-span gambrel roof over that area. (unless you find a steel alternative that towmotor suggests)

Even the original gambrel barns built over a century ago had beams tying the front wall to the back wall to fight against the natural pressure the roof puts outward on the top of the walls.

 

[bp fick]

Give some thought to the load of that second floor. One assumes storage up there? Hay or straw perhaps? How many tons do you envision?

 

[wedge40]

Hate to say this but you are going to have to frame the second floor before you put the rafters up. That is unless the trusses are going all the way to the ground. The reason for this is that the second floor joists also tie the side walls in. The load from the roof has a natural tendency to push the side walls out. So you either have to design some sort of wall tie system or frame the second floor.

Yea the more I though about, you guys are right. I would either have to have a bottom cord to keep the roof from pushing the wall out. Or build a whole second floor.

The second floor wont be for heavy storage, rather more for living space.


Wedge

 

[BungeeII]

Yea the more I though about, you guys are right. I

The second floor wont be for heavy storage, rather more for living space.

Wedge

Living space means you want as little bounce as possible.

You can do what you want, you just want to plan it out before-hand.

 

[wedge40]

Living space means you want as little bounce as possible.

You can do what you want, you just want to plan it out before-hand.

Thats why I'm here asking.

Wedge

 

[civesnedfield]

Thats why I'm here asking.

Wedge

Not sure of your location, but I know by me there is a truss supplier that does Gambrel trusses. They come complete with a floor truss built right into it. I believe that when I was thinking of doing a garage I had planned 32'-0 wide. They had the trusses available in that width. I think the price was around $200.00 each. That was a few years ago. THey way I looked at it though was that after you paid for the floor joists and everything else to frame the floor and roof, it worked out to be a bargin. I would have saved money and a bunch of time going with the trusses.

I have added a pdf file showing the trusses