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Help! the contractor disappeared.insulation

2K views 19 replies 6 participants last post by  Bud9051 
#1 ·
Hi my name is Joe and im new to this forum please be patient with me an let me know if im posting incorrectly. My contractor disappeared during insulation installation. im going to have to finish it myself. i want to install rafter vents but not quite sure what to use. soffit appears to be level with attic ceiling and wondering what would be the best way to install them. i have attached pictures any help would be appreciated.

Thank you
Joe
 

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#3 ·
First thing I would do is double check that those cans lights are I/C (in contact) and air tight fixtures.
There should be a label inside the can where the bulb goes.
As to the amount of insulation you should use that would depend on your location which was not mentioned.
Any place where anything penatrates the ceiling or top plates needs to be air sealed before insulation with expanding foam.
If it was mine I'd be going with blown in.
Lowe's and HD will let you use there blower for free if you buy at least 10 bags of insulation.
One trick I do is lay boards to walk on down the middle of the attic and tape a piece of 3" PVC pipe to the hose they give you with the blower.
That way you can stand in the middle and hit all the way to the baffles.
 
#4 ·
That looks like a very large overhang, if I'm seeing it right, which might eliminate the need for baffles. Baffles keep the insulation away from the bottom of the roof deck. In your case, what is the height above the outside wall top plate and the bottom of the roof. Once we know your climate zone we will know how much insulation you will need.

Whatever you use for insulation you will want a vertical barrier straight up from the outside edge of that top plate to a couple of inches below the bottom of the roof.

Check the rating on the can lights as Joe asked and let us know approximately where you are. Also, that vertical dimension.

Bud
 
#5 ·
I see Buds point, but without baffles there's going to be two issues.
There's just no way to control how far out the insulation blows out when installing and with wind gust it will blow the insulation back from where the top plate is.
 
#6 ·
thank you for the replies. I am in ne pa. the cans are I/C rated using led lights. Bud the top plate to the roof is approx. 18 in. how would you recommend building the vertical barrier i.e what type material etc. cut out for the joist or go over them? sorry if im not using the right terminology

ty joe
 
#11 ·
the wires should have been run in an orderly fashion. then, where they must go over the joist, there should be at least a 2x4 with the wires secured to it.

after you blow in the insulation, and someone has to walk in there. they will not be able to see the wiring. they could trip on it or perhaps damage it somehow.
with a 2x4, they step on the 2x4 and not the wires.
 
#14 ·
I would suggest that the insulation stops AND the soffit materials be installed before you use blow-in insulation, otherwise you will have the dust from the blow-in landing everywhere.
 
#17 ·
on a side note. after you have all work done up there = take plenty of quality high res pics of everything. that way, after the blown in is in, and someone has to do work up there. they can look at the pics to see what is where.

and, if there is no catwalk, put one in. i used 1/2" 2x8 plywood.
 
#18 ·
In your area you will need somewhere between 12 to 15 inches of insulation. You will need to determine what zone applies to you (link added) and what code your municipality is following, 2009 or 2012 (or other)?

https://basc.pnnl.gov/resource-guides/2012-iecc-code-level-insulation-%E2%80%93-doe-zero-energy-ready-home-requirements#quicktabs-guides=3

https://energycode.pnl.gov/EnergyCodeReqs/?state=Pennsylvania

If you are going to go with blown in insulation, with 18" to the bottom of the roof you should create at least a short baffle. The important part will be creating an end barrier to hold back the insulation from falling into the soffit and to protect it from incoming air flow.

I can't see the entire project, but my thoughts would be to add two 2x? the full length of the soffit, one on top of the joists and the other below the rafters. With the inside surfaces vertically above the outside of the top plate you would have a place to attach your vertical barrier. That barrier could be rigid insulation or plywood. It could be cut to fit over the joists and then sealed in place with caulking or can foam.

As for protection at the top, perhaps a 12" strip of something run below the rafters butted against the vertical barrier.

I don't see the commercial baffles working well in your case so fabricating your own will be best. Google "GBA site built ventilation baffles" and click on the link of the same name from Green Building Advisors. If I post the link it makes you sign up to see it Ugh!

Bud
 
#19 ·
ty guys for the info.

so bud in a nut shell what your saying is basically run nailers the length of the addition one at the bottom of the rafter and one over the joists. put abrrier from the joist to the rafter leaving room for a baffle running up the rafter to the ridge vent but just a short run. seal the barriers with foam. is that right?

i do appreciate the help. tired of learning everything the hard way...lol

joe
 
#20 ·
joe, that's basically it. Hard to explain long distance exactly how I would detail it, that will fall on you, but keeping the insulation out of the soffit, protecting the end of the insulation from incoming air, and providing a path for ventilation between the insulation and the bottom of the roof are the objectives.

Also, be sure all air leakage paths from house to attic are sealed before you bury everything in insulation. Take pictures as suggested and hang markers from rafters pointing down to where electrical or other items are buried. I like a raised walkway down the middle of the attic and a few 2x6's on top of the rafters that will be buried but there if and when needed to provide for walking. They can also protect some of the wiring.

Glad to help and hope to see you around in the future. Help forums are incredibly "helpful" and I use them for the many topics where I'm a novice.

Best,
Bud
and what an election.
 
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