sealing, insulating attic - with a twist

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saleen4971

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so we have just received our first bill from the gas company at my first house.

was. not. prepared.

$170! for gas!

fast forward a few days (today) i come home from work, and for the first time was noticing how everyone had a snow covered roof (very light flurries today) - and when i get to my house.....not as much snow. great.

so i plan on sealing the attic over the next however long, and when i have some spare time i will blow in cellulose insulation, but there are a few quirks. my living room used to be a garage, and my garage was sort of just "slapped on" - meaning my roof, soffit, and siding all continue into the garage. not sure how good or bad this is. i will be insulating the garage, but not until fall most likely.

so - seal holes/gaps with regular old fire rated expanding foam i presume? i planned on grabbing a bunch of the plastic vent baffles (one for each existing soffit vent? or should i install more for future rotten soffit replacement this summer?)

as for blocking off the soffit so i dont fill it with insulation (assuming its open right now, but i have not checked) should i use some polyiso sheeting?

in the future i will be adding wiring (stereo, ethernet, power) so i think i may run some PVC conduit beforehand, so i can seal it and cap off for the time being.

only other questions i have are, my attic access is a small opening (average human sized), and i have a large "house fan" - should i just build up walls around them to keep insulation out, and call them "good enough" ??


apologies for the scatter-brain-ness of the post, and many thanks for the input.
 
Fire stop all holes and cracks including light and fan boxes. Check pot lights for insulation safe, if not, build a box around them and insulate that.
Air chutes in ever bay, Staple in place and block the space below with a chunk of batt insulation
.Tack up plywood strips or what have you 16" high between between garage and house, on the garage side of the wall nothing fancy fill any gaps with batt insulation pieces.
Raise the sides of attic access to 16"
Check bathroom fan change duct from 3" to 4" insulated duct.
Glue batt insulation to top of access door.
 
as for the garage part, you mean i should air seal the garage from the house?

i bought 20 air chutes today, will see how far along i get tomorrow with air sealing the house and installing them.
 
Just a high curb so your loose insulation stays where you put it, you do the same when you have an attached roof over a covered porch or deck.
 
Air chutes in ever bay, Staple in place and block the space below with a chunk of batt insulation

:confused:

If you block each soffit opening with batt insulation, won't it possibly interfere with soffit air movement to ridge vent (the chutes having less soffit vent access area)?

Be gentle... I am on an acute learning curve... :hide:

Attic Venting- Rafter Vents _3 (Incorrect Insulation Placement -Blocking Soffit).jpg
 
:confused:

If you block each soffit opening with batt insulation, won't it possibly interfere with soffit air movement to ridge vent (the chutes having less soffit vent access area)?

Be gentle... I am on an acute learning curve... :hide:

Sometimes understanding the question is just as hard as understanding the concept.:p As I am not sure you haven't answered the question already.
I most houses we don't have enough room for insulation above the wall, heat will travel thru the wood structure of the top of the wall the the rafters and that is what causes ice damming where it is cold enough. So if we can't keep the roof cold with insulation we use cold air to do that job.So there is a balance of how much insulation and how much air flow. As there is no variety of sizes of chutes you just use it as is.
Even with out freezing conditions we want to keep the roofing as cool as we can in the summer.
We can put chutes in every bay even if there is no soffit vents in the area, hopefully the soffet are is flat on the outside give a common area for air to move to where ever the heat is moving air up and away.
Even if there is no common area in the siffet area the chutes alone will enable the heat to rise to the attic and create a circulation of sorts.
With trusses today we often have heal cuts high enough for insulation over the wall but then you still need something there to stop the loose insulation from falling into the soffit area .

Does that help.
 
OK... It is starting to sink in...

All depends on the soffit design.

Back to book learning... ;)

Would using insulation board in lieu of (Fr ?) rafter chutes be feasible as shown in the ill below if the soffit design will allow it and there is little chance of blow-in insulation going behind the boards?

As Usual- THANX!

Attic Venting _1- Ridge-Gable-Soffit Venting.jpg
 
OK... It is starting to sink in...

All depends on the soffit design.

Back to book learning... ;)

Would using insulation board in lieu of (Fr ?) rafter chutes be feasible as shown in the ill below if the soffit design will allow it and there is little chance of blow-in insulation going behind the boards?

As Usual- THANX!

The biggest source of heat lose in the attic is the outside wall in you diagram they have the foam board fixed to the bottom of the rafters. Rafters have a birds mouth cut on the bottom to sit on the wall. So in that situation the wall will have foam over maybe an inch the rest of the wall will be non insulated.
So yeas you will have more air flow but you also have to move more heat.
You don't need a lot of air flow as the wall likely wouldn't feel warm to the touch, you just don't want it trapped there, it just needs enough space so it can meander up the inside of the roof and cool off.
In the summer time if we assume that the attic will always be warmer than the house, do you want warmer air in contact with the top of that wall.

In that drawing there is also a wall vent. That is a short circuit where air from the soffit could be drawn out that vent leaving no airflow or less air flow at the peak. Or with a wind air could enter there and go the peak leaving no or less air flow at the soffits.
.
 
The thin plastic rafter vents are much cheaper than foam board and can easily be stapled into place. The attic is going to be insulated anyway, so the foam is overkill.
 
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https://www.youtube.com/watch?v=ABj3TTkZH9c[/url [URL]https://www.youtube.com/watch?v=Mg4b9gBbAV8

[ame=https://www.youtube.com/watch?v=ABj3TTkZH9c]-AttiCat DIY Attic Installation Instructions[/ame]

Referring URL Corrected By- DUKE of URL... ;)

Great instructional video. I see their baffles have tails to prevent blown-in insul from covering the soffit vents.

Gable vents in addition to ridge vents. There are arguments on either side but I tend to agree with blocking off any gable vent with a ridge vent but can also install faux (Fr ?) gable vents for decoration.

THANX AGAIN!
 
-AttiCat DIY Attic Installation Instructions

Referring URL Corrected By- DUKE of URL... ;)

Great instructional video. I see their baffles have tails to prevent blown-in insul from covering the soffit vents.

Gable vents in addition to ridge vents. There are arguments on either side but I tend to agree with blocking off any gable vent with a ridge vent but can also install faux (Fr ?) gable vents for decoration.

THANX AGAIN!

They bend the bottom of the chute down but they end up with no insulation over the wall. I would sooner see the chute extend some into the soffit area and block below that with batts.
 
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