# Gambrel Attic Roof Truss



## ETD66SS

I want to build a barn with an an apartment in the attic.

I want the barn to be 40 x 60 with no poles supporting the ceiling/floor for the apartment.

First off, is this possible, or would I need to go to a smaller span?

If this is possible, where do I get the dimensional information for the truss required?

I have a little program called Easy Rafters http://www.easyrafters.com/, that calculates the truss based on span. However I need information on what size lumber would be required to span 40' with no load beaing poles, and also the center spacing of the trusses.

I'll contact a lumber yard I know that builds trusses, but was looking to see if I could find this information on the net...

Was hoping someone here could help me!

Thanks!


----------



## jbob

Your trusses/joists would need to be engineered for a 40 foot span,
especially with a live load on the 2nd floor.

Steel web joists would be required for a 40 foot span, the size to be
determined by an architect or engineer.

I have used engineered wood joists spanning up to 26 feet.
If you could somehow split the span to 20 feet, these would
work for you and save the cost of engineering. Your truss
company should have items like this pre-engineered.

Splitting the span without posts would be expensive.
A 60 foot glu-lam would cost a fortune in fabrication,transportation,
and installation.

Good Luck


----------



## ETD66SS

Well, I just talked to a local truss manufacturer, explained what I wanted and they are going to send me a few options...

From the way the guy sounded on the phone, 40' span was not a big deal...

Only thing he said was a they have to be 12' or less in height to ship...

That means a pretty squatty Gambrel Roof for a 40' span...

He said they also offer a split truss & I-joist system, where I build the floor with sheeting first, then put up the slpit trusses. It's more work, but I actually like that idea better...

He's going to give me prices too...


----------



## Bonus

I built a 36'x36' building with a 17'x36' upstairs in it. These were trusses and if I remember correctly was an 8/12 pitch. The bottom chord was 2x10, the top chords 2x6. They came flat on a truck, weighed about 400 lbs each.


----------



## wct62

I have been a truss designer for the past 16 years on and off. A 40 foot Gambrel truss should pose absolutely no problems. As for the 12 foot delivery width restriction, there are a couple of different options. The trusses can be designed with a hinged top portion which is folded up after the trusses are erected. I personally dont like this option because there are too many chances for the hinge joint to be damaged in handling, unloading and durring erection. The better option would be to cap the truss. This involves designing a truss to a shipping width of 12 feet and having a second truss which sits on top of the first. Ive used this method literally hundreds of times. Talk to your truss manufacturer about this option. Hope this helps. I just wonder why they didn't suggest this solution...


----------



## ETD66SS

Well, I talked to the truss designer. He looked at using a split truss. Where the truss would come in two halves. He told me that design would not work, as the 40' span was too great for a split truss.

I came up with a solution, whereby I use a regular 5/12 pitch shed truss on top of second story walls wich are 30' apart, then frame in the lower section of the gambrel with stick & frame constructuon. The upper stud wall will sit on floor trusses that can handle the 40' span. This will also enable me to stick frame in the dormers without hacking apart any of the trusses...

You can see my design in the following picture. The purchased trusses are shown in red. I'm looking at ~$12,000 in trusses...

http://usera.imagecave.com/bhaal/Carriage_House/Truss_Config.JPG


----------



## Bonus

I hope that price includes the floor trusses, seems high to me.


----------



## ETD66SS

Yes, the floor trusses are the expensive ones...

I need 31 of them, and they are ~$280 each...

2x8 for the cords, 2x4 for the webs...

24" tall floor trusses...

The roof trusses are $90 each, and all 2x4 construction...


----------



## Bonus

Gotcha, good luck.:thumbsup:


----------



## KnifeGarage

ETD66SS said:


> Well, I just talked to a local truss manufacturer, explained what I wanted and they are going to send me a few options...
> 
> From the way the guy sounded on the phone, 40' span was not a big deal...
> 
> Only thing he said was a they have to be 12' or less in height to ship...
> 
> That means a pretty squatty Gambrel Roof for a 40' span...
> 
> He said they also offer a split truss & I-joist system, where I build the floor with sheeting first, then put up the slpit trusses. It's more work, but I actually like that idea better...
> 
> He's going to give me prices too...


I too am looking for information on Gambrel trusses. I have a 30 x 50 floor plan. I' m attempting to put a second floor on and I liked the idea of a split truss system that was pictured. I am trying to maximize space usage.


----------



## Gazelle

*Truss*

Hey,

Capping a 40' truss is not a problem, done all the time.

The hinge as stated is problematic and most contractors don't like 'em

Caution: If you do decide to go with an I-Joist or Floor Truss system make sure the point loads generated from the knee wall from the roof down to the floor system is accounted for!



Gazelle, <'/))))><
www.wwtbi.com


----------



## KnifeGarage

*Gambrel Roof*

Thanks for the website. It had some pretty good information. My hope for a Gambrel style roof slipping a bit. I am try to maximize storage space on a second level so I am thinking of doing full two story with 4/12 roof top. I my change the pitch if i cannot keep the peak below 25 feet. As you can see I am somewhat flexible on the second story.

Thanks 
KG


----------



## Wolfman51

If you still have not sorted out the problem then check out, www.barnplans.com ,they will provide you with the plans for the complete building including engineered trusses.All you then have to do is decide the size of the building and where you want to put the walls for the rooms inside


----------



## KnifeGarage

Thanks for your response. The website is a great reference. Still in planning phases so I have not completely decided on the final plan yet. Stiil looking at 30' X 50'.


----------



## crecore

your plan looks like a good compromise if it passes engineering with your local loading. Make sure you specify ceiling load, dead load and live load for living space not attic storage to all be factored in along with truss, roof and snow load for those "bottom cord trusses." A design as this will be very specific with fasteners, brackets and bracing. Make sure to follow that.

Bonus... your picture looks almost identical to a garage I built last year. Im on the laptop right now but I'll post a picture tomorrow.


----------



## KnifeGarage

Looking forward to your pictures.


----------



## crecore

sorry it took so long, I never posted pics here before. I'll try


----------



## crecore

OK it worked. 36'x36' with 2' step on the gable for looks. Site built attic trusses 7/12 pitch, full drop gables, double 12" LVL ctr beam (made install a lot easier without a dynalift), 12' wide attic room.


----------



## KnifeGarage

*Knifegarage*

Your Pic's looked great. i ended up going the full two stories. I will begin in early May. It'll be big, but worth it in the end. Unfortunately while building my own roof trusses would be a serious task i am would be willing to attempt at another time. Still have a house to build when i am done with this one. Time is on my side at present. I snap some photos and see it i can return some copies your way.


----------



## Skyfuzz

Does anyone know of a website or available program to assist me in planning attic roof trusses for a 42 wide by 30 deep garage. Just like ETD66SS, I want to keep it open down below with out support poles.


----------



## crecore

knife, a friend nearbye went the two story route. Lots of space but looks odd next to his house. He did a nice job though. Then, his neighbor essentially copied his...lol.

I built my own because my local contractor salesman said I was crazy and it couldnt be done. When I was done he did marvel at how straight and strong the roof was but said he wouldnt take back saying that I was crazy. lol


----------



## KnifeGarage

It'll be big. But I have almost 4 acres and alot of old trees growing nearby. I think the size is relative. It should be 25' at the peak. I see alot of possiblilities and flexability in my building. Also i think that with 2 boats, 4 four wheelers, 5 vehicles and a growing woodworking shop I might need more someday.

Knife


----------



## crecore

*garage*

Mine is about 21' to the peak, so yours will be way higher than that! I can draw it all up for a price if you're interested.

[email protected]

Chad


----------



## KnifeGarage

Crecore.

I have drawings already from Punch Professional Home Design. The only thing that I could not do was draft in the floor trusses. Maybe in another version. I appreciate the offer for your help. it is actually the floor trusses that are adding the addition hieght. i wanted the freedom of not having a bunch of walls supporting the second level. I will be starting in a couple weeks on construction. 

Knife:thumbup:


----------



## dsowinski

*Gambrel Attic Outcome*

I am looking into doing something very similar and was wondering what the outcome was for ETD66SS' project. Specifically, what type of floor trusses (depth, spacing, style) did you end up going with? Were there any gotcha's that you encountered?


Regards,

David


----------



## comp

dsowinski said:


> I am looking into doing something very similar and was wondering what the outcome was for ETD66SS' project. Specifically, what type of floor trusses (depth, spacing, style) did you end up going with? Were there any gotcha's that you encountered?
> 
> 
> Regards,
> 
> David


interested myself


----------



## crecore

there's probably one reason we didnt hear back from him...

*$$$$$$*

could surely be done. I would do a steel beam and steel trusses at that size. They be a lot lighter and they'd be pieced together in the field do to transport height. To engineer a field platable two piece wood truss requires way overbuilding the joint areas.


----------



## olgoatone

*Can it be done*

How hard would it be to build a gambral roof ,two story home with a clear span width of 62 feet not counting overhangs.in addition the clear span(great room)will be 40feet with no supporting structure.The upstairs will have a room over the great room. as large as the roof will allow, with no short walls.This will act as a bunk room when the family(5 children,13 grand kids, and expecting great grands)(will have 3 spare bed rooms on first floor).
planning to use Murphy beds along the walls,with entertanment center on one end of the room.Also two full baths.
I am also planning a very large garage(62x76)with a woodworking shop(38x30),with garage parking for 6 cars and a full length upstairs finished room for storage.The upstairs floor will need to be fairly strong.about half of the garage will be clear span.
:huh:


----------



## NewEnglandEOD

*Floor trusses*

Slightly off-topic from gambrel roof trusses, but on the topic of floor trusses:

Next spring I'm going to tackle a remodel on the attached carriage house to my 1897 Victorian. The carriage house is 25x50, and I want to clear span the first floor, with an apartment (live load) on the second floor. From the reading of the posts here, that sounds completely feasible with floor trusses.

So, my questions:

1. I'm going to have to remove the siding as well as replacing much of the plank "sheathing", as a good bit of rot has set in on several walls, so I'm fairly certain I can wiggle the trusses inside from the second floor that way. However, the next problem I'm facing is that the walls are balloon framing. The mudsill is 12x12 and the walls are 2x4 with some 4x6 poles, so I have room to basically build new walls abutting the older ones and still be on the foundation. My plan was to build these new (not to mention straight, plumb and level) walls and set top chord bearing floor trusses on them. Am I completely out of my mind, or will this work?

Sorry if some of my terminology is off, I've been out of the construction field for a while.

Thanks.


----------

