attic insulation

[heyttown]

I have a 2 story house which I need some help with attic ventilation.. My house does not have any soffit overhangs on the front or back. I have 5 roof vents that were cut in with my new roof, and without overhangs and soffit vents the roofer recommended vented drip edge to try and get some intake into the attic. I have short walls on the outside walls with sloped ceilings in the bedroom that are 2x4 rafters. I purchased styro-foam baffles to install to allow air flow. I went into my attic and removed the insulation that went down the roof pitch and blocked my new vented drip edges..While I have all that insulation out, I figured my unrestricted air flow would help cool the attic in the summer, but it let more heat into the house then cool my attic...Being the airflow is minimal if any from my drip edge venting, Im tossing around the idea of completely sealing the (approx) 4ft of sloped ceiling space that heats the bedrooms off with spray insulation making it airtight and should minimize the heat coming into the bedrooms, and adding powered vents on the sides of the house for intake ... Somehow I need the increase the air intake and reduce the heat transfer that comes into the bedrooms through these 4ft sloped walls in my bedrooms. Ive also tossed around the idea of using the styrofoam baffles and cutting 2" pink foam to slide down the sloped ceilings, but the R value isnt that great for the styrofoam... any ideas or thoughts?

 

[bruceb58]

Re: attic insulation

Cooling the air in your attic really doesn't help you a lot assuming you have enough insulation.

I also think I lost you on what your configuration. Maybe a picture would help

 

[rbh]

Re: attic insulation

"BIG" Gable end vents could be an answer.

when we redid our roof with tin last year we put in a ridge vent, that made a huge difference.

 

[bigdee]

Re: attic insulation

Cooling the air in your attic really doesn't help you a lot assuming you have enough insulation.

I also think I lost you on what your configuration. Maybe a picture would help

Bruce is absolutely correct. There have been a lot of people scammed out of good money trying to cool their attics. Ventilation is for moisture removal NOT cooling. Put your money in more insulation above the ceiling and definitely add insulation above your sloped ceiling and be sure to use the air-space baffles.

 

[rbh]

Re: attic insulation

Bruce is absolutely correct. There have been a lot of people scammed out of good money trying to cool their attics. Ventilation is for moisture removal NOT cooling. Put your money in more insulation above the ceiling and definitely add insulation above your sloped ceiling and be sure to use the air-space baffles.

Theory behind venting
The intent of roof venting varies depending on climate, but it is the same if you?re venting the entire attic or if you?re venting only the roof deck.

In a cold climate, the primary purpose of ventilation is to maintain a cold roof temperature to avoid ice dams created by melting snow and to vent any moisture that moves from the conditioned living space to the attic.
In a hot climate, the primary purpose of ventilation is to expel solar-heated hot air from the attic or roof to reduce the building?s cooling load and to relieve the strain on air-conditioning systems. In mixed climates, ventilation serves either role, depending on the season

 

[bruceb58]

Re: attic insulation

Theory behind venting
The intent of roof venting varies depending on climate, but it is the same if you’re venting the entire attic or if you’re venting only the roof deck.

Should have just put in the link where you did your cut and paste from.
http://www.finehomebuilding.com/how-to/articles/a-crash-course-in-roof-venting.aspx

There is so much more thermal mass below the ceiling that the little extra that you are cooling down by further venting the attic is minimal assuming proper insulation in the ceiling.

Powered attic vents are a complete waste of money. Install a whole house fan instead.

 

[rbh]

Re: attic insulation

^^^^

Are you the cut and paste police??

Heytown, are you talking about a dormer area that your trying to cool down.
I now undestand what your talking about after I reread, your upstairs is alot like ours
When the house/dormer was constructed, if the framers did not use a high enough piece of wood say
a 2x4 VS 2x10 on edge you probably will be hard pressed to get "good" air flow and minimum code insulation.
So you could treat this like a bathroom "kinda, sorta" and vent with a fan from the highest point of the room to the outside with the biggest CFM bathroom fan you can find "or" drop the ceiling down 4-6 inches so you have room for both insulation and air flow.

But I would go with just opening the ends of the house on the gables with a 2 foot x 2 foot vent to get air flow to the open section of your attic and intern this will draw off a little of the heat build up above the bedroom.

 

[bruceb58]

Re: attic insulation

Are you the cut and paste police??

Just figured it would be nice to have the whole article where you are getting your info from.