Planning: Ceiling and insulation for outbuilding

[The Lazy Destroyer]

Over the past couple weeks I've been working on insulating the walls in my outbuilding, now I need to start looking at a ceiling w/ insulation. But this poses a lot more questions than I had about insulating walls

For reference, this is on a detached garage, 40'x22', bottom chord of the trusses is at about 14' and the trusses are 2x4 trusses on 24" centers.

Major thing that needs to be done is insulate. The roof gets pretty darn warm in the summer and you can feel it when you get up high in my garage. I have a gable vent fan to draw some air out but it still gets warm in there. For the insulation, I am not sure if I should plan to insulate like I have been doing for the walls: fit insulation between studs and staple... then install the ceiling? Or should I plan to install the ceiling and then come in after that from the top and drop the insulation onto the ceiling that way? I will likely be doing batts (R19 or so?) but not sure which part would normally be done first? Ceiling panels or insulation?

For the ceiling I am thinking OSB or plywood, not exactly sure just yet. I checked out some material at the local Lowes. The thick stuff (5/8" or so) feels heavy as hell. So I am concerned about the weight I would have to deal with when installing. I have a drywall lift with the extension bar, and may likely rent a scaffolding system... but even with these it just seems like it would be hard to deal with.

So I have been thinking about using furring strips on the bottom of the trusses (at maybe 12" centers) so that I can use a thinner/lighter panel. Would there be any problem with this? If I put them at 12" centers, what thickness could I go with on the paneling?

If I did the furring strips method, would I want to install the insulation first and staple it to the 2x4's, since there will be a slight gap from the furring strips at the bottom of the trusses? Or would not not matter?

 

[The Lazy Destroyer]

Here are some pictures of the outbuilding for reference:

 

[samert111]

I used R30 Kraft faced fiberglass batts stapled between the truss chords and then the white metal Durapanels from Menards. With the scaffolding it's light enough to work with.

 

[pattenp]

You can face staple 24"kraft faced insulation to the truss and then apply the furring strips on 12" centers. With 12" centers on the furring strips I think you can get by with 1/4 inch thick paneling on the ceiling. The gap between the insulation's kraft face and the ceiling panels will not matter.

 

[paullie]

I used R30 Kraft faced fiberglass batts stapled between the truss chords and then the white metal Durapanels from Menards. With the scaffolding it's light enough to work with.

i did it like this but used blow-in fiberglass

 

[Dick in Wisconsin]

I used R30 Kraft faced fiberglass batts stapled between the truss chords and then the white metal Durapanels from Menards. With the scaffolding it's light enough to work with.

I'm planning on doing the same thing. Is there a trick on the electrical outlets in the ceiling? Do you install the boxes as you install the panels so that you get the box centered in the flat area of the planel and keep it away from the rolled portion?

 

[The Lazy Destroyer]

Did some quick research and I like the Durapanels, but looks like it is not available in my area. Anyone know if there is an equivalent available in the SouthEast area? Otherwise that looks pretty good and the price is not bad!

I had looked at Lowes/HD not too long ago and perused through their metal roofing section but didn't see anything, the while paneling I did see was expensive if I remember right, and was thicker than what I needed it for.

Some time ago... someone posted a picture of their ceiling, they had OSB/plywood IIRC and glued & nailed cheap wood laminate flooring to the ceiling, and it turned out pretty good from the pics. That was my plan and why I had been looking at OSB, so that I can finish it up w/ the laminate.

 

[The Lazy Destroyer]

You can face staple 24"kraft faced insulation to the truss and then apply the furring strips on 12" centers. With 12" centers on the furring strips I think you can get by with 1/4 inch thick paneling on the ceiling. The gap between the insulation's kraft face and the ceiling panels will not matter.

Is there a particular size furring strip that is recommended? Looks like most available is 1x2 or 1x4?

 

[pattenp]

I'd use the 1x4 because it would provide better stiffness. I do like the looks of the Durapanel shown in the above post.

 

[pattenp]

I wonder if vinyl soffit would work? It's carried at Lowes and HD.

 

[samert111]

I'm planning on doing the same thing. Is there a trick on the electrical outlets in the ceiling? Do you install the boxes as you install the panels so that you get the box centered in the flat area of the planel and keep it away from the rolled portion?

****,
When putting it up I found the best method for locating the light boxes was once I got to one I moved it a little to fall in the flat area then took some measurements and put the metal panel up then drilled a 1/2" hole where the box was and then cut the hole out with a set of Weiss red handle tin snips. The red handle snips are for cutting curves to the left or counter clockwise. I'm left handed so those worked best for me.

 

[Dick in Wisconsin]

****, When putting it up I

THANKS! That is what I was thinking. Tack the boxes in loosely ... move the center and then cut. I'm right handed!

 

[The Lazy Destroyer]

I like the soffit idea. A bit pricey judging by what is available at HD and Lowes. I'm thinking about finding a siding supplier to see if they have anything comparable to the Durapanels or anything like it.

Worst case I can always fall back on the 1/4 plywood w/ white paint. Cost shouldn't be too bad!

I think for now, just to get the heat alittle more under control, I may insulate between the trusses, staple the kraft faced batts, and maybe use those metal support rods to keep it held up in place for now. Or go ahead and use the furring strips to help hold it up.

I assume there should be no issues insulating and just doing the finished ceiling at a later time?

 

[HotrodHR]

Do yourself a favor and insulate and sheetrock your ceiling... cheaper in the long run.

Why would you want to use OSB on the ceiling? BTW, how would you fasten laminate floor to the ceiling... glue?

The soffit material from Lowes would work but can get a little pricey...

 

[kbs2244]

I am assuming a white roof in GA.
But how much ventilation do you have up there?
Continuous ridge with lots of soffit vent were designed for you.

 

[The Lazy Destroyer]

black roof. Don't see many white roofs here. No ridge/soffit vents, just two gable vents on each side. One has a 1600 cfm gable vent exhaust fan on a t-stat.

 

[The Lazy Destroyer]

Do yourself a favor and insulate and sheetrock your ceiling... cheaper in the long run.

Why would you want to use OSB on the ceiling? BTW, how would you fasten laminate floor to the ceiling... glue?

I won't be finishing the ceiling so taping/mudding is out. I would not mind using t-molding on the seams and just simply paint that, so that could be an option. But I have heard a lot of people avoiding drywall on unheated/cooled garages and I wanted to avoid any problems that may come from the temps if in fact the insulation did not help as much as I was hoping. I do not plan on heating/cooling the space until next year at the earliest.

I have seen quite a few people on here using OSB on their walls and ceiling and it looks just fine to me. In fact the only reason I may lean towards plywood instead of the OSB for the ceiling is I assume the OSB would be harder to paint, if I went with white paint.

Can't find the original post but the laminate flooring was glued and brad nailed from what I remember. It looked really good to be honest.

 

[Mmfh]

The last place I had I stapled up the Insulation, making sure it was tight everywhere, and that was it for several years.

So, if you just want to put up the insulation and that's it for now, as you asked earlier, it will be fine and give you some time to figure out what you want to do to finish it.

 

[tlmartin84]

Why not use 1/4" instead of 1/2" or 5/8" OSB. Thats what I plan to use, and the doing blow in fiberglass. Good looking shed BTW.

 

[The Lazy Destroyer]

Another question - Should I shoot for R-19 or R-30 for the ceiling insulation?

I assume it is a "buy as much insulation as you can afford" situation. If I hold off on the ceiling paneling and do it at a later time... I can probably swing R-30 in the budget.

If I do not plan on heating/cooling the place for the time being, just using fans for the area for now, would it be in my better interest to spring for the higher R-value? Or is there a reason it would not matter too much if the place is not conditioned?

 

[Riverside]

Did some quick research and I like the Durapanels, but looks like it is not available in my area. Anyone know if there is an equivalent available in the SouthEast area?

I believe that Durapanel is just one brand of the metal siding / liner panels that are used on metal buildings. The 29 ga. thickness would probably be fine for your use. Any metal building supply place will have it. I think the Atlanta Craigs List includes metal building supply ads.

 

[Varkwso]

The problem you will have with OSB and 1/4 inch plywood here in GA (I am near Augusta) is warping from heat and humidity. I used 15/32 plywood sheathing on inside walls and 6" insulation to reduce warping and give me a hard surface to hang what I want. I have metal rafters and metal roof with ridge vent plus a 2800 cfm fan with humidity and temp settings. I am planning on using the foam panels and big headed nails to attach to the wood stringers between my metal rafters (I have really high inside ceilings). They will not provide a lot of insulation but enough to help with a good air gap.

The ridge vent will give you a lot of passive heat and moisture relief.