Insulation question

[tikkalover]

Problem with an attic fan is, they have a tendency to suck snow into the attic.

 

[Wallike]

I put my attic fan on a thermostat that comes on only when it gets above 80 degrees. Works great for helping cool the house in the summer.

 

[3Roosters]

 

[JayKay]

Uhh, I could be wrong. It's actually likely. But shouldn't the attic fan be drawing air OUT of the attic? Is it possible that yours is wired in reverse? The air comes in along the eaves, and exits at the peak, or near the peak. The attic fan should be drawing air OUT, not in.

The air in the attic should be the same temp as outside. Especially in the winter. That's why your ceiling is insulated, and not directly under the roof sheathing.

If you've noticed, there are nearly always the tips of nails sticking into the attic, through the roof sheathing. If it's too warm in the attic in the winter, a frostball will develop on the tips of these nails. Melts, drips, insulation gets wet. Wet insulation sinks, loses r-value.

Sounds like if the house is hard to cool and heat, there is not enough insulation in the attic.

And yes, an attic fan is often controlled by a thermostat. Does nothing in the winter, but exhausts hot air in the summer.

 

[BrokenBackJack]

Maybe he is talking about a whole house exhaust fan that mounts in the ceiling. It sucks air in your house from open windows/open doors and exhaust the air out the attic. Seen lots of them down here in AZ.

 

[Petras]

I relooked it has vents on the main home -- but the connected garage nothing --- can i cut vents into the shingles without messing them up?

Dammit i just put some in my currrent stand alone garage so i could heat it and now the wife throws a wrench in it.

I would install ridge vent. Stupid easy to do, and you don't even see it unless your really looking for it. It's really easy,. Remove ridge cap, string a chalk line 2" down from the peak on each side of the peak. Use a circular saw to cut along chalk lines. Stop your cuts about 16-18" from each end. Remove the strips you just cut out. Roll out ridge vent and nail in place. Next you put your ridge cap shingles back on. It's stupid easy to do and I'm sure there's plenty of videos out there on how to do it.

 

[Maddog]

I relooked it has vents on the main home -- but the connected garage nothing --- can i cut vents into the shingles without messing them up?

Dammit i just put some in my currrent stand alone garage so i could heat it and now the wife throws a wrench in it.

Depends how handy you are.

You can put the "pot vents" in. To remove shingles in the area of install. Cut hole in roof sheeting (not at a roof truss .....). In stall pot vent with overlap shingle(s) on the bottom and then install removed shingles overlapping the flanges on the pot vent cutting the shingles to match the side and top profiles of the pot vent (not the flanges....). Also to put roofing adhesive (black) around perimiter of pot vent flanges (bottom surfaces) when installing.

You can put the ridge vent in. Remove existing cap shingles at roof ridge and top row of shingles at both sides of ridge. With circular saw cut "just" through the roof sheeting (depth of cut) at the ridge leaving at gap per the recommendation of the ridge vent. Install ridge vent per instructions that comes with them.

Somewhat oversimplifying, but it isn't rocket science. Or like my son says, google it and someone has a youtube video on how to do it.

Good luck.

Sorry, I didn't read Petras post below.
Do the ridge vent .....

><><
Talk to a insulating contractor about attic insulation etc.
They will have a wealth of information for you.

For our home location he recommended 24" of blow insulation in the attic. 24" being somewhat the point of no return where added insulation does little/no benefit for keeping cool in summer and warm in winter. Meaning the payback (years) gets to be very long when you go with more than 24". For YOUR locale, maybe the 24" is different. You to do the legwork to find out what that insulation height should be.

I beg to differ that the attic "has" to be the same as the outside air temp. Realistically that is very hard to do. Especially on my house with limitied/no trees, a steep roof and one story (ranch). There is a lot of roof/shingles. And a lot of air in the attic---- that heats up like an oven For example recently on a hot day I measured 118 degrees in the attic just above my 24" of insulation. At the bottom of the blow insulation it was 78 degrees. In the inside of my house at the ceiling it was 77 degrees. The outside temperature was 88. I have soffit vent chutes (the plastic ones) between each truss along the soffit of the house. And I have a ridge vent. It stlll gets "hot" up there. Hot being relative. If one does the engineering to determine the air flow to get the temp "the same" as the outdoor temperature, my gut says that will be a lot of air flow. Meaning I will need a couple of "huge" fans.

BrokenbackJack -- I like your comment about the whole house fans. One of my friends has it and likes how it works. My question is how does one insulate for in the winter. So that you don't have a lot of heat loss (air) through the whole house fan location.

 

[BrokenBackJack]

Depends how handy you are.

You can put the "pot vents" in. To remove shingles in the area of install. Cut hole in roof sheeting (not at a roof truss .....). In stall pot vent with overlap shingle(s) on the bottom and then install removed shingles overlapping the flanges on the pot vent cutting the shingles to match the side and top profiles of the pot vent (not the flanges....). Also to put roofing adhesive (black) around perimiter of pot vent flanges (bottom surfaces) when installing.

You can put the ridge vent in. Remove existing cap shingles at roof ridge and top row of shingles at both sides of ridge. With circular saw cut "just" through the roof sheeting (depth of cut) at the ridge leaving at gap per the recommendation of the ridge vent. Install ridge vent per instructions that comes with them.

Somewhat oversimplifying, but it isn't rocket science. Or like my son says, google it and someone has a youtube video on how to do it.

Good luck.

Sorry, I didn't read Petras post below.
Do the ridge vent .....

><><
Talk to a insulating contractor about attic insulation etc.
They will have a wealth of information for you.

For our home location he recommended 24" of blow insulation in the attic. 24" being somewhat the point of no return where added insulation does little/no benefit for keeping cool in summer and warm in winter. Meaning the payback (years) gets to be very long when you go with more than 24". For YOUR locale, maybe the 24" is different. You to do the legwork to find out what that insulation height should be.

I beg to differ that the attic "has" to be the same as the outside air temp. Realistically that is very hard to do. Especially on my house with limitied/no trees, a steep roof and one story (ranch). There is a lot of roof/shingles. And a lot of air in the attic---- that heats up like an oven For example recently on a hot day I measured 118 degrees in the attic just above my 24" of insulation. At the bottom of the blow insulation it was 78 degrees. In the inside of my house at the ceiling it was 77 degrees. The outside temperature was 88. I have soffit vent chutes (the plastic ones) between each truss along the soffit of the house. And I have a ridge vent. It stlll gets "hot" up there. Hot being relative. If one does the engineering to determine the air flow to get the temp "the same" as the outdoor temperature, my gut says that will be a lot of air flow. Meaning I will need a couple of "huge" fans.

BrokenbackJack -- I like your comment about the whole house fans. One of my friends has it and likes how it works. My question is how does one insulate for in the winter. So that you don't have a lot of heat loss (air) through the whole house fan location.

I would think a thick blanket of insulation on top of it in the attic for in the winter. I would put down plastic on the top of it in the attic and then add a thick blanket or two of insulation. That is what we did in our houses in NoDak for the access cover to the attic.