Questions about blown-in cellulose prep

[b-boy]

I'm finishing up insulation on my pole barn walls this weekend. I have 2" foam board and unfaced fiberglass batts for the walls. My walls will be R22.

After I finish running electrical, I'd like to do the ceiling. I plan on doing blown-in cellulose or fiberglass, in the ceiling. I won't be using it for storage.

I have galvanized steel panels for the ceiling. I will add a plastic 6-mil vapor barrier to the joists as well.

My questions are:

• How do I prep the ceiling for this?
• What access do I need to leave for the installation?
• Do I need to leave multiple panels open for access or do I just leave 1 panel and attempt to walk the rafters? They're 4 feet apart, so I'd rather not do this.
• Is it standard practice to leave a permanent access point into the attic area? How do most people insulate this access point?

 

[FTG-05]

What I would do:

How do I prep the ceiling for this? Great stuff foam for all small openings and cracks etc.


What access do I need to leave for the installation? Whatever you currently have. You'll need ~10' feet access of every portion of the attic, maybe a bit longer if you use a broom stick.


Do I need to leave multiple panels open for access or do I just leave 1 panel and attempt to walk the rafters? They're 4 feet apart, so I'd rather not do this. Whichever is more convenient. I would leave what you have as-is.


Is it standard practice to leave a permanent access point into the attic area? How do most people insulate this access point? Yes. Simple piece of R-19, R-30 fibercrap insulation over the access door. Make "dams" for the cellulose so it doesn't fall out when you open the door.

Good luck!

 

[b-boy]

How about making sure that the insulation doesn't block the eave vents? Is there something I can do to make sure that won't happen? Any sort of blocking required for blow-in insulation?

 

[Kaizen]

How about making sure that the insulation doesn't block the eave vents? Is there something I can do to make sure that won't happen? Any sort of blocking required for blow-in insulation?

Easiest thing is foam pieces you stick down in the eaves and staple to the roof. Saw another way using tyvek or plastic stapled to the top plate and hung over a string that went the length of the building


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[kd3pc]

in our part of TN, they often use cardboard soda cases...supposedly they fit 16" on centers easily or two of them to do 24". The edges bend easily and staple in even easier.

 

[FTG-05]

Easiest thing is foam pieces you stick down in the eaves and staple to the roof. Saw another way using tyvek or plastic stapled to the top plate and hung over a string that went the length of the building


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Easiest is blowing the insulation in, covering the entire attic floor - including the vents (or not caring if you do cover them).

Then go around with a blower from the ground and clearing the vents from the outside. 2nd floor houses might require a tube extension, but it's still easier than trying to access the vents from the inside and blocking them off.

I've done it this way four times now and it's usually a 20 minute job +/-; 30 minutes for the one two story home I did years ago.

This is especially true for homes with low attic roofs; having to crawl around on 2x4's, hoping to not fall through the ceiling drywall, *****.

 

[Kaizen]

Easiest is blowing the insulation in, covering the entire attic floor - including the vents (or not caring if you do cover them).

Then go around with a blower from the ground and clearing the vents from the outside. 2nd floor houses might require a tube extension, but it's still easier than trying to access the vents from the inside and blocking them off.

I've done it this way four times now and it's usually a 20 minute job +/-; 30 minutes for the one two story home I did years ago.

This is especially true for homes with low attic roofs; having to crawl around on 2x4's, hoping to not fall through the ceiling drywall, *****.

Sorry but that seems like lazy. Chances of not all blowing out and sitting in the later blocking the vents. Op has no ceiling yet so easy to do it the right way.


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[FTG-05]

Sorry but that seems like lazy. Chances of not all blowing out and sitting in the later blocking the vents. Op has no ceiling yet so easy to do it the right way.


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If it works, then it's not lazy, it's smart.

Definition of "Works": Simple, go up into the attic during the day, don't turn the lights on and look at each vent. If you can see daylight as from a clear vent, there you go.

And who decided your way was the only "right way"?

 

[Kaizen]

If it works, then it's not lazy, it's smart.



Definition of "Works": Simple, go up into the attic during the day, don't turn the lights on and look at each vent. If you can see daylight as from a clear vent, there you go.



And who decided your way was the only "right way"?

I don’t see respectable contractors doing as you described. when giving advice I go with industry standards if op has no knowledge about the subject. If it was a foolproof method I’m sure they would be using it. Works for you great. But don’t set up op for issues.


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[FTG-05]

I don’t see respectable contractors doing as you described. when giving advice I go with industry standards if op has no knowledge about the subject. If it was a foolproof method I’m sure they would be using it. Works for you great. But don’t set up op for issues.


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And what issues would that be? I mean other than the fact you don''t like or approve of it.

And it pretty much is foolproof. Far more foolproof than baffles that could be plugged and not being able to see it.

And I haven't even mentioned the safety part. If there's anything worse than blowing insulation in an attic during the summer, it's balancing on a couple 2x6's trying to install some baffles - with 1'-2' head clearance.

 

[OptionalStop]

I would install the baffles at the eaves and bring up a few 2 x 12 boards to lay across your trusses to act as a scaffold.

 

[Kaizen]

And what issues would that be? I mean other than the fact you don''t like or approve of it.



And it pretty much is foolproof. Far more foolproof than baffles that could be plugged and not being able to see it.



And I haven't even mentioned the safety part. If there's anything worse than blowing insulation in an attic during the summer, it's balancing on a couple 2x6's trying to install some baffles - with 1'-2' head clearance.

Think I’d be concerned it is blocked to some degree and no way to see it was blown out. A little bit can clog a big area. Great solution for ten years later and someone wants to make sure they are clear.


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[Dragfluid]

OP, take a look at my ceiling insulation in my build thread. (link below) It shows how I made an inexpensive catwalk down the center.

 

[spam4us]

this

 

[Ohmthis]

^^^^^^Hell Yeah!!!

 

[justinjoyal]

I don’t see respectable contractors doing as you described. when giving advice I go with industry standards if op has no knowledge about the subject. If it was a foolproof method I’m sure they would be using it. Works for you great. But don’t set up op for issues.


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I agree.

Blowing the stuff out from underneath? Honestly i would run away if i saw anyone doing that.

Cellulose will get carried by wind. If nothing is in place to keep it away from the vents, you’re looking at trouble.

This is what’s used here in Quebec (french instructions but you can see how it’s installed from the drawing):

Obviously this is for 24” C/C trusses which are code here. The principle stands for whatever spacing there is. You can use another material. You just want something to keep the insulation in place.

 

[NUTTSGT]

Make your scuttle or access hole big enough for you to get through easily. I'd also not make it too close to the edge where the roof line comes down to far.

Personally, I like a 2'x4' access hole will give you plenty of room.

 

[850xpeps]

Easiest thing is foam pieces you stick down in the eaves and staple to the roof. Saw another way using tyvek or plastic stapled to the top plate and hung over a string that went the length of the building


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They sell wax coated cardboard “insulation stops” that have ends with creases for folding 16 or 24” o/c spacing. These are the best. I’d ereccomend a gable vent acces hatch then your going in from the exterior and can entirely blow your whole ceiling with no holes in your vapour barrier.