Vent baffles for pole building?

[bullnerd]

What have you pole building guys used for vent baffles between the roof rafters/trusses?

My trusses are 4' on center.

It would be nice to span the 4 feet in one shot.

I plan to blow in insulation.

I tried searching but didnt see any pole building examples.

 

[383]

We usually install a batt of r19 fiberglass insulation at the eave between the trusses to keep the blown insulation from going out onto the soffit. It is usually stapled to the truss support before the ceiling is installed. You can use whatever R value you want, just be sure it isn't thick enough to close off the space between the support and the roof, so there is still adequate ventilation.

 

[wcs6523]

I used a 4 foot wide roll of cloth material sold at menards used to hold blown insulation in wall cavities. I stapled it to the bottom of the top truss board so there is a gap the size of a 2x8 all the way out to the eve.

 

[68 Bird]

I had some extra 7/16" osb laying around after my build and ripped it down to 2' wide, 4' long and nailed them to the underside of the trusses right at the soffit.

 

[bullnerd]

Thanks for the tips guys.

WCS-strange place for your first post(I must have inspired you)but thanks.

I guess there is no specially made foam gizmo like the standard ones?

 

[68 Bird]

Thanks for the tips guys.

WCS-strange place for your first post(I must have inspired you)but thanks.

I guess there is no specially made foam gizmo like the standard ones?

I looked around a lttle but nothing to fit 4' OC trusses without extra framing. I was able to burn up some left overs plus it was way cheaper than anything I saw factory made.

 

[bullnerd]

Thanks bird.I dont have enough scraps to do 80 ft. but I'll keep it in mind.

What about the vapor barrier material?The plastic sheet stuff.I can lay it on "top" of the truss and just slit it to pull it down around the rafter.Might be a PIA to do though with it falling down.

 

[68 Bird]

Thanks bird.I dont have enough scraps to do 80 ft. but I'll keep it in mind.

What about the vapor barrier material?The plastic sheet stuff.I can lay it on "top" of the truss and just slit it to pull it down around the rafter.Might be a PIA to do though with it falling down.

You don't need to do the full length. Of course if that's how you punched the soffet vents in then yes. I just baffled a total of 24' each side , 6-2'x4' baffles on each side. Thats 3 sheets of 7/16 OSB, ~$30. As long as the soffet intake square inches are greater than the exhaust square inches up top, you'll be fine.

 

[68 Bird]

You don't need to do the full length. Of course if that's how you punched the soffet vents in then yes. I just baffled a total of 24' each side , 6-2'x4' baffles on each side. Thats 3 sheets of 7/16 OSB, ~$30. As long as the soffet intake square inches are greater than the exhaust square inches up top, you'll be fine.

See the attached image.

 

[bullnerd]

Thats a good point Bird,I didnt think of that.I had the full length in my mind.I forgot it actually opens up to one big "attic" space.

I have full vented eves and a continuous ridge vent.

I have to go take another look.

BTW-thanks for taking the pic,that helps.

 

[Highbeam]

Great thread. I plan to use the single batt in the first cavity to create the dam.

Instead of OSB, it may be cheaper to buy the rigid foam in .5 or one inch thickness. That would give you some Rvalue and may be easier to install.

 

[bullnerd]

What do you mean by "first cavity"?

I was also thinking about the foam.

 

[Highbeam]

What do you mean by "first cavity"?

I was also thinking about the foam.

The first cavity being the first joist space. The ceiling has joists every 24" and the first 24" space being FG batt will allow the blower guys to stay clear of the edge where all the ventilation takes place. The batt will act as a dam and a guide.

 

[bullnerd]

DUH....now I get it!

I was thinking eve side.

Thanks for the tip.