Insulation stops for 48" oc

[Tracs]

I am going to install insulation stops in my new 40x60 but might have a slight problem. Insulation will be blown in R50.

1st. What do people use for insulation stops for 48" oc trusses?

2nd. The position of my roofing purlin is directly about my top plate. If I run a insulation stop from the back of the top plate, up to the underside of the roof and then up and forward as usual, it will run right into the purlin.

If I ran the stop from the top plate, up to the purlin, and then toward the peak, would the profiles in the metal roof provide enough air flow?

I could leave the stop down a inch from the purlin, but I am trying get the most R value I can.

 

[NUTTSGT]

I'm curious if the ribs would allow enough air flow as foam baffle does that is normally used in attic ventilation.

 

[jack stand]

Typically you'd staple a baffle to the bottom of the first couple of roof purlins for ventilation and install a half of a "batt" of r 48 to actually do the closing of the space into the un insulated overhang. This is the normal installation by a insulation contractor for 2' truss spacing.
I don't see why they wouldn't treat 4' spacing the same but with 2 baffles in between and maybe running a full r 48 batt in between the trusses for the stop.
I'd have your contractor out for a discussion of your options and his suggestions. You will probably have to at minimum run 1x4 "strapping" 2' o/c to attach the ceiling material to, 4' is out of the question for drywall and pushing it more than I would for metal.
He might suggest a layer of poly first then your strapping.
Some might suggest a layer of rigid foam then strapping.

 

[Notgrownup]

Make your own out of cardboard

 

[driver50x]

Question, Do the soffits have to/need to be vented for an insulated garage? The guys building my shop were supposed to use vented soffits, but they used solid instead…….

I’m in St. Petersburg, FL. So this is mostly just for air conditioning.

 

[racecougar]

I went with heavy plastic sheeting to make my own. It has worked very well for 7 years thus far (I just poked my head up there a couple months ago to check for any issues).

Question, Do the soffits have to/need to be vented for an insulated garage? The guys building my shop were supposed to use vented soffits, but they used solid instead…….

I’m in St. Petersburg, FL. So this is mostly just for air conditioning.

Is the ridge vented? Is there a ceiling in place? What type of insulation?

 

[Innovate1]

I think I would cut some strips of OSB or plywood to fit between the trusses. You could tack the lower end to the outside of the top plate. Then angle it in so it's inside the purlin at the top. If you need to go higher run a strip parallel to the roof deck but down an inch or two - you will need to tack some scraps of wood to the sides of the trusses to attach it unless you get a really good fit and angle the fasteners. Or maybe lay it on top of the trusses.

What Jack Stand suggested sounds like it would work too and be a lot less work.

 

[Innovate1]

Question, Do the soffits have to/need to be vented for an insulated garage? The guys building my shop were supposed to use vented soffits, but they used solid instead…….

I’m in St. Petersburg, FL. So this is mostly just for air conditioning.

Venting will help with air conditioning by keeping the area above the ceiling cooler. You need a ridge vent or some higher vent for it to do much. I would have them change it if you still are able to.

 

[driver50x]

I went with heavy plastic sheeting to make my own. It has worked very well for 7 years thus far (I just poked my head up there a couple months ago to check for any issues).








Is the ridge vented? Is there a ceiling in place? What type of insulation?

Yes, there is a ridge vent. No ceiling yet. I’m planning on a metal ceiling. Probably fiberglass batt insulation. I’m also not sure if the facing should go up or down in my area. There seems to be mixed opinions on that.

 

[racecougar]

Yes, there is a ridge vent. No ceiling yet. I’m planning on a metal ceiling. Probably fiberglass batt insulation. I’m also not sure if the facing should go up or down in my area. There seems to be mixed opinions on that.

Yes, you should have vented soffits. I would get your builder to correct this.

 

[Tracs]

Typically you'd staple a baffle to the bottom of the first couple of roof purlins for ventilation and install a half of a "batt" of r 48 to actually do the closing of the space into the un insulated overhang. This is the normal installation by a insulation contractor for 2' truss spacing.
I don't see why they wouldn't treat 4' spacing the same but with 2 baffles in between and maybe running a full r 48 batt in between the trusses for the stop.
I'd have your contractor out for a discussion of your options and his suggestions. You will probably have to at minimum run 1x4 "strapping" 2' o/c to attach the ceiling material to, 4' is out of the question for drywall and pushing it more than I would for metal.
He might suggest a layer of poly first then your strapping.
Some might suggest a layer of rigid foam then strapping.

I am my own contractor/builder/insulator. I'm cobbling along on my own.

I have read about using fiberglass batts as the stop itself.

I also like the other ideas in the thread, like using poly as insulation stops.

I could tape together pre-made cardboard insulation stops, but at $3.55 a piece and needing 120 of them it will get pricy.

 

[billconner]

Tough problem. Could you use two 24" baffles in each space, and attach with adhesive or spray foam? Protecting the air flow from soffit onto baffle will be tricky.

 

[jack stand]

I am my own contractor/builder/insulator.

If there's a fair amount of building going on within 20-30 miles I'd highly suggest getting a quotation from an insulation contractor. It's likely that they'll supply & install it for less than you'll be able to buy it!
You're building is a big enough project to get their attention and talk about something that's "gravy" work where a lot of insulation can go in in a short time, I'm sure they'll be interested.
Really, get a quote and compare it to what you're material costs will be.

 

[NUTTSGT]

I think I would cut some strips of OSB or plywood to fit between the trusses. You could tack the lower end to the outside of the top plate. Then angle it in so it's inside the purlin at the top. If you need to go higher run a strip parallel to the roof deck but down an inch or two - you will need to tack some scraps of wood to the sides of the trusses to attach it unless you get a really good fit and angle the fasteners. Or maybe lay it on top of the trusses.

What Jack Stand suggested sounds like it would work too and be a lot less work.

I have often thought of using some polyiso or other rigid foam board to accomplish this as well. No need to buy high dollar stuff but if "seconds" are available in your area.

 

[Innovate1]

I have often thought of using some polyiso or other rigid foam board to accomplish this as well. No need to buy high dollar stuff but if "seconds" are available in your area.

Seems like there would be lots cheaper options than rigid foam. Any tips on finding this cheap? I am wanting to insulate the under side of some hollow core concrete in a room under my porch. Was planning to get the blue/pink rigid foam and glue it up and glue something over it - maybe thin plywood.

 

[NUTTSGT]

Seems like there would be lots cheaper options than rigid foam. Any tips on finding this cheap? I am wanting to insulate the under side of some hollow core concrete in a room under my porch. Was planning to get the blue/pink rigid foam and glue it up and glue something over it - maybe thin plywood.

I found mine on CL. They were (are) an Amish family that had a source for it. Granted they were about an hour away but when you buy a bundle of 24 sheets for about 50¢ on the dollar, it made it worth the drive... besides, I now know where they are for future reference or purchases.

This is he place I found and their website. I'd guess their stock changes from day to day. If I needed more rigid foil faced, I would call them first.

Flooring and Barns | Glenford, Ohio | Graber’s Oak Flooring

Graber’s Oak Flooring installs flooring, barns, and more in Ohio. Visit our site to see our many service options.

www.grabersoakflooring.com

Also link to when I bought them and put them up.

Garage Refurb®

Looking great!

www.garagejournal.com

 

[Innovate1]

I found mine on CL. They were (are) an Amish family that had a source for it. Granted they were about an hour away but when you buy a bundle of 24 sheets for about 50¢ on the dollar, it made it worth the drive... besides, I now know where they are for future reference or purchases.

This is he place I found and their website. I'd guess their stock changes from day to day. If I needed more rigid foil faced, I would call them first.

Flooring and Barns | Glenford, Ohio | Graber’s Oak Flooring

Graber’s Oak Flooring installs flooring, barns, and more in Ohio. Visit our site to see our many service options.

www.grabersoakflooring.com

Also link to when I bought them and put them up.

Garage Refurb®

Looking great!

www.garagejournal.com

Thanks! I did a quick look on FB marketplace and found a place in Iowa that has seconds for about half price. Both places are too far to justify but I will do a bit more looking.

 

[NUTTSGT]

Thanks! I did a quick look on FB marketplace and found a place in Iowa that has seconds for about half price. Both places are too far to justify but I will do a bit more looking.

Keep looking. It helps if you know someone else that needs some and they can help split cost of fuel. The positive is that the stuff weighs practically nothing. I just advise taking a piece of OSB/Plywood to sit on top to strap over you you don't bury the strap into the foam board.

The other option is make it into a day trip with the wife.

 

[Dragfluid]

This is what I did in the good shop. 1/4" OSB, ripped in half. Used the same material for the cavity caps, as I was using dense pack cellulose in the walls.
You mentioned you're putting R50 in the attic. Please go R60. You're in Canada. I put 20" of cellulose in mine, as it will settle a couple inches. Buy once, cry once.

 

[Tracs]

This is what I did in the good shop. 1/4" OSB, ripped in half. Used the same material for the cavity caps, as I was using dense pack cellulose in the walls.
You mentioned you're putting R50 in the attic. Please go R60. You're in Canada. I put 20" of cellulose in mine, as it will settle a couple inches. Buy once, cry once.

How did you fasten the OSB to the top plate/trusses?

 

[Dragfluid]

How did you fasten the OSB to the top plate/trusses?

I figured that you'd be asking that, and I've been trying to remember. It's been over ten years. But I believe I just pounded a couple of nails up towards the top of the OSB into the truss. The OSB is up tight against the tin, as the grooves provide plenty of air flow. And the bottom of the OSB is sitting down on the plate. They didn't go anywhere. I had easy access to the attic afterwards, and I had made a couple trips up there over the seven years that I had the building and everything was always A-OK!
The link for that build thread is still down below. Please take a look at it. Lots of ideas that you may be interested in.

 

[NUTTSGT]

I figured that you'd be asking that, and I've been trying to remember. It's been over ten years. But I believe I just pounded a couple of nails up towards the top of the OSB into the truss. The OSB is up tight against the tin, as the grooves provide plenty of air flow. And the bottom of the OSB is sitting down on the plate. They didn't go anywhere. I had easy access to the attic afterwards, and I had made a couple trips up there over the seven years that I had the building and everything was always A-OK!
The link for that build thread is still down below. Please take a look at it. Lots of ideas that you may be interested in.

The ribs proved to be enough air flow ?

That's nice to know. I was wondering about that in my first post.

 

[Innovate1]

I would want a little more open space than just the ribs. But it would be easy to tack a few scraps to the top edge of the OSB to give a bit more. Can't have too much ventilation up there.

 

[jack stand]

I don't know the actual math that's involved with proper "open attic" ventilation, but the opening in the Styrofoam baffles that are commonly installed every 2' (at 2' o/c truss layout) is probably about 36 sq. inches open each.
You'll have about 5 or 6 of the ribs in 4', I'd estimate that to be about 2 sq/in per rib or approximately 12 square inches per 4' vs approximately 72 sq/in using 2 baffles.
I'd do a little internet surfing before you make up your mind.
I also believe that you can't have too much ventilation in any space outside of your insulation "envelope".

 

[Dragfluid]

To those that don't think that the ribs are enough, then the OP just needs to put a couple of short blocks on the OSB as Innovate suggested. The main point is, it's an easy solution to his question.

 

[jack stand]

The problem is that on top of his wall looks to be about only 8-9" away from the tin, that's only about half of the r value he's looking for and by the time he gets to the approximate 16" for an R 50+/-, he'll be up near the next roof purlin in. Ventilating this aprox. 2' up slope run properly calls for the baffles.
Holding the proposed osb down to allow air movement up to the peak will reduce the insignificant (estimated) 8" to anything less will be a significant heat loss along both walls equating to about 160 s/f.
Sure it's easy to rip down some osb, but the OP is looking for a R50 also. 80' of osb blocking will probably buy the baffles, definitely if he's not buying retail.
He really needs to get an estimate or 2 from insulation contractors even if only to purchase the materials.

 

[Stoshu]

Can’t really see if I’m right in your pictures. Looks like you used clipped head framing nails in your hurricane ties. I hope you aren’t getting inspected. they are pretty fussy about using proper fasteners.

 

[Tracs]

The problem is that on top of his wall looks to be about only 8-9" away from the tin, that's only about half of the r value he's looking for and by the time he gets to the approximate 16" for an R 50+/-, he'll be up near the next roof purlin in. Ventilating this aprox. 2' up slope run properly calls for the baffles.
Holding the proposed osb down to allow air movement up to the peak will reduce the insignificant (estimated) 8" to anything less will be a significant heat loss along both walls equating to about 160 s/f.
Sure it's easy to rip down some osb, but the OP is looking for a R50 also. 80' of osb blocking will probably buy the baffles, definitely if he's not buying retail.
He really needs to get an estimate or 2 from insulation contractors even if only to purchase the materials.

Those are my thoughts as well. I don't want to lose any precious space for the already inadequate insulation above the top plate.

I have bought all the fiberglass batts and blow in cellulose already and when the time comes I will blow it in myself. I get contractor pricing at the lumber yard (I know the owner and says I get same pricing as the biggest contractors).

I need 60 baffles @ 3.55 each plus taxes. I was wrong about needing 120.

$240 for baffles
8 sheets of OSB - $180.

 

[mike93lx]

I'm going to make stops from a roll of housewrap for my shed

 

[Sumboodie]

Make your own out of cardboard

Or plywood/osb

 

[Tracs]

Update

I ended up buying insulation stops and taping them together. When installing them I made sure to leave 1" from the horizontal purlins for airflow.

 

[MRsingletrack]

I had the same dilemma on this. I used 2 baffles per 48" OC, I sealed off with foam board 5" thick to increase the R value of the low heel. Also installed some 1/2" foam between the baffles. I then sealed with spray foam. Totally overkill.