Shop Addition Begins

Hey, Folks!

Got a question for you. As some of you might remember, my wife and I have been in the process of moving from Bradenton, Florida to Thomasville, Georgia. Well, I'm finally at a point that the slab is being poured for my shop extension later this week. After discussing options with a couple of local contractors, I'm fairly certain that the overall design of the addition is OK.

The existing building measures 16' wide by 24' deep. I'm adding 20' to the width and retaining the 24' depth. The addition will be a gable roof extending from the side of the building. The roof of the addition will be a 4/12 pitch and the height of walls will be dimensioned to make the facia mate to the existing building facia. To allow for some additonal ceiling height in the addition, I'll stick-build the roof rafters and ceiling joists per the attached drawing. I'll use Simpson steel straps at the ridge beam and where the rafters join the top plates of the walls. Roofing material will be composite shingles on 3/4" deck to match the existing building.

Do you see any issues with the strength of the rafter/ceiling joist arrangement? I want to use this layout to get 10' clearance over the working area of the addition. Walls and roof structure will be 16" centers.

Thanks for your input.

(By the way, it ain't been fun trying to set up the new place with my wife still living and working in the Tampa area. She's much better at housework than I am!!!)

Long time Bill, Miss you around the Creek.
Bigger is better.:cool:

Bill, my question is on looks, not strength. If I read your post right, you're attaching a shallow-pitch roof onto the side of a tall barn-roof type structure. I would be concerned with that looking odd. I'm having a hard time mentally meshing that drawing with that photo, but I wonder about a taller and steeper roof, to fit better against this structure.

Edited:
Here I grabbed your picture and drew on it -- is that what you have in mind?
(or maybe on the other side) Where would the peak of the addition hit the side of the existing barn? I'd aim for higher than I drew, hitting right at the bend of the other roof. But I admit, I'm not a builder, I'm just playing with looks...

Have fun with it!!

Art echoed my thoughts. I'm wondering if another gambrel roof is appropriate at right angles to the existing structure for continuity of design. I know that for a utility building this isn't always a priority, but then again, it may make the property more desirable in the future when it needs to be. And as much as I don't prefer that roof style, it does have big advantages when it comes to head-room!

BTW, nice to see you back posting!!! I don't envy you with the move outside of the opporunity to "play" at creating a new home and shop...

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Originally Posted by Art Mulder

Bill, my question is on looks, not strength. ...

Edited:
Here I grabbed your picture and drew on it -- is that what you have in mind?

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Thanks for your input Art. You too Jim.

You've got the general idea. I've considered several options and this seems to be the least objectionable approach. Ideally, I'd split the addtion between each side of the building, bring a shed roof down from where the roof breaks. There's not enough room between the property line and the left side of the building to do that, though.

I attached another drawing that shows the front view pretty much to scale. The new roof will intersect the existing roofline at the halfway point of the first segment, yielding a 4/12 pitch which is fine for this area. From an appearance standpoint, I'm thinking that using a low pitch, then dark shingles to match the existing building will play down the roof line a bit. Siding on the existing building is hardy plank, so I'll match that on the addition.

My main concern is the roof structure itself. I'm not a structural engineer by any stretch of the imagine, but I did have a long talk with a local general contractor about my intentions. From all of the research I've to date, my layout should be as solid as necessary. The ridge beam, rafters and joists will be 2x6 for added strength and rigidity.

What I'm really looking for is whether someone sees a "gotcha" related to the roof. I've done some stud wall framing and have no issue with building the walls, but I've never done this type of roof.

Hopefully, I can get back to participating in the forum on a more routine basis going forward. Of course, now that I say that I'm about to get real busy on the shop addition! :eek:

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Originally Posted by Tyler Howell

Long time Bill, Miss you around the Creek.
Bigger is better.:cool:

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Thanks, Tyler. My wife agrees with you, also! :D

Bill - Were it me, I'd raise the roof such that the ridge lands at the hip of the gambrel. I'd do so mostly for aesthetics, but a steeper roof with collar ties located about a third of the way up from the plate towards the ridge should also provide for a stronger truss. Here's a crude edit to your drawing.

Attachment 49372

Yup. More materials, but that's just money:confused:

I also would blend in the addition as shown above. Dismantling the old and creating a whole new roof line is a much bigger job! I like the proposals above and would probably do Andy's idea to get you the 10' heigth in the addition. Looks better this way too...

Not that my opinion matters, but I agree with Andy and Art. I would try to mimic the same Gambrel dual-pitch roofline with the addition. It'll mean more work, but in the end you'll have structure that is architecturally consistent AND you'll have more attic space to boot. However, I can also appreciate the economics of building simple structures instead of complex ones.

I think Fine Homebuilding covers framing Gambrel roofs in one of their framing/roofing books, if not a back issue article I read a while back. I'll have to double-check.

Bill, good to see you back in the creek. Looking at the drawings I support Andy's for looks and additional storage. What ever you decide enjoy your shop and please keep us posted.

Frank - I was actually thinking of just a simple A-Pitched gable, not another gambrel roof profile.

Andy - Sorry...I wasn't able to tell from your CAD drawing ;). I still agree with the higher roofline.

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Originally Posted by Frank Snyder

Andy - Sorry...I wasn't able to tell from your CAD drawing ;). I still agree with the higher roofline.

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LOL ! First time I've ever heard Paintbrush referred to as a cad program:eek:

I have framed a lot of roofs like the one you have drawn and the long term result of cathedral ceilings with high collar ties is bowed walls and sagged ridges. Not much but if you are looking you will be able to see it especially if snow sits up there (dont know about that where youlive but up here it is a regular thing). Fortunately the solution is an easy one. Add a structural ridge beam made from engineered lumber (LVL- probably 2 of them 14 or 16" deep). I would consult an engineer for the design or the local lumber yard should have programs developed by the engineered lumber mfgrs that will be able to do this design quickly and for free. This is easier if you are buying the materials for the garage er shop from them.

The other benfit of this plan is that it gives you a rock solid lifting point should the need ever arise. BTW we never use 2x6 for rafters because they are just too narrow. The way lumber is today, one big knot will render a 2x6 useless and that might be after it is installed and has a chance to shrink. Step up to 2x8 (or more- you only benfit when it comes to insulation and R values) for those spans (your rafters are going to be at least 14'- think about how flexy a 14' 2x6 is).

This sounds complicated but a trip to your lumber yard with some sketches and maybe pics of the existing garage will help and it shouldnt cost anything.

Good luck. Ben

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Originally Posted by Ben Grunow

The other benfit of this plan is that it gives you a rock solid lifting point should the need ever arise.
Good luck. Ben

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One word of caution. If you invision ever using the beam as an anchor for lifting let your lumber yard know. Using thier sizing software they can place a point load anywhere along the beam and size it correctly for your needs. An extra 2" in depth now is much cheaper than the alternative! :eek:

Thanks to all for your input.

I'll post photos occasionally as the project moves along.