# Preparing for blown in insulation in difficult attic



## Randallflagg (Sep 24, 2016)

So in my tri-level home 1 of my attics was easy to install soffit vent channels but the second attic, a hip roof with a very shallow slope is going to be near impossible. So I am trying to figure out a way to vent the attic properly. I have also noticed that due to the way it was constructed 1/2 the bays have a 2x6 in the middle of them anyway. The slope is 4/12 and the roof is approximately 33'x29'.

Little lost on this one, I think the only way to get them in there is to come from the outside, which I did around the chimney when I replaced sections of rotted soffit.


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## joecaption (Nov 30, 2011)

Near imposable is the key, not fun but it can be done.
Lay a piece of cut plywood down so you have a place to lay.


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## Randallflagg (Sep 24, 2016)

joecaption said:


> Near imposable is the key, not fun but it can be done.
> Lay a piece of cut plywood down so you have a place to lay.


Yeah, that is what I did for the other attic, not fun but was doable. This roof has even less pitch but I haven't tried to get one in there.

I was looking for an out, haha. So when I get them up there and have 1/2 of the bays done is that fine?


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## Randallflagg (Sep 24, 2016)

Quick shot of what it looks like, which doesn't give you the best view but its something.


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## stick\shift (Mar 23, 2015)

Nope, not fun but doable.


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## joecaption (Nov 30, 2011)

Has this attic ever been air sealed?
In NH you need R-12 of insulation which would be about 12" of insulation.Would have been far better off with blow in insulation.
So far we have 0 info on how much or even what type soffit venting or roof venting you have.
https://www.energystar.gov/index.cfm?c=home_sealing.hm_improvement_insulation_table


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## Randallflagg (Sep 24, 2016)

joecaption said:


> Has this attic ever been air sealed?
> In NH you need R-12 of insulation which would be about 12" of insulation.Would have been far better off with blow in insulation.
> So far we have 0 info on how much or even what type soffit venting or roof venting you have.
> https://www.energystar.gov/index.cfm?c=home_sealing.hm_improvement_insulation_table


Nope, that was on the audit report and will be done around the time or around when the vents are added. I have massive 24" soffits with a channel all around the house for venting. This is a house built in '69 with preexisting unfaced batts laid down.

The other attic we put a large gable vent in when we re-sided as well as about 3/4 of the bays have the soffit baffles installed. This large attic only has soffit vents, the inspector recommended adding a couple of roof vents.

I am going to be going adding either R-38 or 49 with blown in on top of the exiting unfaced batts (there is a vapor barrier below the rafters and above the sheetrock).

Soffit pic:


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## Windows on Wash (Aug 30, 2011)

If you are doing all this work, I would definitely air seal and insulate first as Joe mentioned. 

After that, loose fill blown in cellulose topper is great.


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## Randallflagg (Sep 24, 2016)

Windows on Wash said:


> If you are doing all this work, I would definitely air seal and insulate first as Joe mentioned.
> 
> After that, loose fill blown in cellulose topper is great.


Yes, that is the plan, it's really having correct venting that I am concerned about.

I am going to have to find some smaller baffles for the bays with 2x6's in them, but I think I need more ventilation on the hip roof and don't know the best way to go about doing so.


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## Bud9051 (Nov 11, 2015)

How much ridge do you have, if any. If no ridge then you will need several roof vents up high. Got a picture of the outside?

I'm sure you have seen the ventilation calculators, but if not we can go over it here and more importantly advise what is best with a lot of low venting and limited high venting.

Bud


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## Randallflagg (Sep 24, 2016)

Bud9051 said:


> How much ridge do you have, if any. If no ridge then you will need several roof vents up high. Got a picture of the outside?
> 
> I'm sure you have seen the ventilation calculators, but if not we can go over it here and more importantly advise what is best with a lot of low venting and limited high venting.
> 
> Bud


Sadly I just found the calculators, hadn't even thought of something like that.

I have almost no ridge, what I was looking at picking up was a 14" diameter static vent.

Best roof pics I have:

















Oh and the ridge from the inside...


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## Bud9051 (Nov 11, 2015)

You could go with hip ridge vents up those slopes. If you have 120' of that vent you would have 1,200 in² of NFA, or 8.3 ft². That's a lot.

Is the hip roof area separated from the roof to the right or do they share an attic connection?

What is the attic floor area?

Be sure the baffles you install include a flap to block the incoming air from blowing on the insulation. If fiberglass, it will suffer wind washing.

Bud


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## Windows on Wash (Aug 30, 2011)

Ridge vent on the lower and 750's on the hip roof.


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## Randallflagg (Sep 24, 2016)

Bud9051 said:


> You could go with hip ridge vents up those slopes. If you have 120' of that vent you would have 1,200 in² of NFA, or 8.3 ft². That's a lot.
> 
> Is the hip roof area separated from the roof to the right or do they share an attic connection?
> 
> ...



Honestly installing 4 hip ridge vents would be way more work than just a few vents, I'm not even sure how comfortable I feel installing a ridge vent... 

Attics do not share a connection, just a couple holes I have made to run cables. 

about 1000 sq ft.

if they had a blocker I wouldn't be able to do anything with it, I can't get my arm all the way into where the soffit starts. I am just shoving them past the insulation using a broom handle.



Windows on Wash said:


> Ridge vent on the lower and 750's on the hip roof.


Would there be an issue installing a ridge vent on the lower roof where it meets the upper?

And lastly, I have 2 layers of shingles (ugh) what is the proper way to install the vent? under both at top and over both on bottom?


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