Temporary attic insulation help.

[Banjorear]

OK, the house we just bought is having terrible ice damming on the roof. The insulation that's in there now is just between on the floor and not on the rafters. We do have pull down stairs for our attic.

First off, the insulation is old and poorly done. I want to bring someone in to put blow some more (loose: either fiberglass or other) over it.

We will eventually need a new roof so I'm holding off on doing anything under the rafters until that is done.

I noticed that HD sells a "tent" type thing that goes over the opening to the pull down stairs to prevent heat loss.

Two things: Does anyone now if that tent type of heat trap works?

What should I be looking for when re-insulating the floor of the attic? How think should I go?

Thanks.


Tim

 

[awdblazer]

if your having ice daming look into your roof venting

 

[Banjorear]

if your having ice daming look into your roof venting

That's the problem, there isn't any.

 

[awdblazer]

there is your problem then
your attic should be at approximately the same temp as the out doors

 

[James-W]

I agree, you need to stop as much heat loss thru the ceiling as possible and you need to get some vents into the attic to get rid of the heat that is there, preferably soffit vents and a ridge vent. Adding more insulation is a good start, but without the proper attic venting you will still have the problem.

 

[Randy in Maine]

After winter ends, you should get up there to see if you should add some addtional venting up there in the form of a ridge vent, gable vents, and soffit vents to allow the roof to be "outside temps" on both the outside and the inside of the roof. Add addtional insualtion in the attic if needed to keep you expensive heat inside.

The general exception to the rule above is that if you don't have any air to move around, (like me since I have spray foam on my cathedral ceilings) venting is not required.

When you do the new roof, be sure to strip off all of the roofing to inspect the roof sheathing for rot and to put bitchathane under the entire roof. Cheap insurance to preventing leaks.

 

[Dick in Wisconsin]

You could have air infiltration between the house and the attic too. Do you have frost on the underside of the roof?

While poor insulation and not enough ventilation of the attic contribute to ice damming, I've concluded that ice damming can be caused by a combination of:

1. Lots of snow.
2. Outside air temps between 26 and 32 degrees.
3. A sunny day.

The sun warms the roof which warms the attic which melts the snow.

The water runs down to the roof above overhang which is below freezing and freezes. As soon as the sun goes down the roof gets cold and everything freezes. The next day with the same temps ... it all starts over again. This is especially acute on the north and east sides of the house.

If the outside air temps move into the high 30's or better yet into the 40's ... then the water (melted snow) won't refreeze on the roof over the overhang or in the gutters or in the downspouts and you won't have an ice dam.

I think you can have the best possible insulation with the NO air infiltration from the house into the attic and with the right outside air temps, a sunny day, and dark roof you're going to have ice damming if you have lots of snow on the roof. Even if you have lots of insultation.

Consider putting one of those remote thermometers in the attic and monitor the temp in the attic. You'll learn quite a bit about how your house performs.

This is going to be HUGE year for ice damming in lots of the country.

 

[sselander]

I made a foam box for my attic stair opening.
I used the pink foam board and the adhesive used to glue foam boards.
I just lift it up and push it aside.
I needed to shave a little on the side for the side hinges to fit.

 

[Scott H in Wheaton]

DO NOT INSULATE YOUR RAFTERS!!!

Insulation goes on the floor of your attic to keep heat in your home, and to block attic heat from going in to the home in summer.

The underside of the roof needs to breathe...don't choke it off with insulation.
Ventilate to get rid of moisture and equalize the attic temperature to the outside.
Insulation to stop warm air from migrating into the attic space, hitting the cold air and turning in to condensation.

 

[MonoxieChild]

^
What if you have a full walk in attic? This is something ive been thinking about in my own 2300SF home. I spend a bit of time in my attic as its full height and a walk up. But specially this winter has just been frigidly cold. My plan was to insulate the open rafters, But now im questioning what is my best option.

And at least around me, EVERY house has ice damming this year.

 

[Sloper0204]

Look into hot roof systems. There are plenty of ways to insulate your rafters and either maintain air movement or turn your roof into a hot roof system.

Building Science has some interesting articles on roof design for exactly this.

 

[TractorJeff]

Randy in Maine says, "The general exception to the rule above is that if you don't have any air to move around, (like me since I have spray foam on my cathedral ceilings) venting is not required."
Which means MonoxieChild could insulate his attic to create a room.

 

[MonoxieChild]

Thank you Sloper! Ive searched, but never knew the correct term for my attic and set up, and never found anything really helpful. But just knowing the term "Hot air roof" gave me hours of reading this morning.