Attic insulation

[Walter Cohen]

I have an unfinished attic in my NY house. The attic is bordered on one (in)side by a bedroom and on part of another (in)side by a bathroom and hallway. The other part of the attic (crawl space at best) is over the back patio. The attic space has a small double-hung window at one end (I always keep it open for ventilation) and a few small round air vents in the patio ceiling.

The previous owner (can't imagine the original builder doing this) has placed foil-faced insulation, with the foil facing inside, between all rafters in th eattic on the underside of the roof. [If I take the insulation away there is the wood tongue-in-groove roof material and on top of that just a layer of asphalt roofing shingle]

Does the insulation do anything for me? Is it the correct insulation to have - foil faced with the foil showing inside? There is no insulation on the inside walls up against the bedroom/bathroom/hallway as mentioned above. Do I need and should I put insulation in between the wall studs here?

Thanks for your help. Walter

[Tony Hwang]

Yes. I'd go for R40.

Yes. R20 on the walls.

[m Ransley]

Foil down is correct, insulate wherever there is heat loss. You cannot have to much inslation. Remember your code is minimum requirement for R value. R 50- 70 can be used in cold climates in attics.

[Greg]

Unless you live somewhere that the A/C is on more than the heat. You want the foil toward the warm moist air. In Florida (for example) that is in the attic most of the year.

[Michael Daly]

Are you saying the insulation is on the underside of the roof and not resting on the floor of the attic? If so, then no, the insulation is doing nothing. Since you're keeping the air space well ventilated, the insulation is not between your heated space and the air. The insulation will keep the heat on the roof from making the attic hot, but it won't help in the winter.

You want the insulation on the floor of the attic. If you finish the attic and make sure that the underside of the roof can breathe, then the insulation goes on the inside of the roof. That makes the attic an insulated, heated, usable space.

Mike

[v]

Well, he's/she's half way there now. It seems like this is a half attic - there already are finished heated rooms bordering it, and the walls between these spaces and the "attic" are not insulated.

So the 1st thing he/she needs to do is CLOSE THE WINDOW (during heating season). And treat this area as a heated space.

Right now, he/she is opening (with the window) this space to the exterior, with NO insulation between heated rooms and the space in Q.

-v.

[Walter Cohen]

Part of the reason I leave the window open constantly is to help prevent ice dams in the winter. And I wouldn't say the air space is 'well vented'. I wish I had more ventilation than I already do (which is not much as it is only the open window and two tiny air vents at the far corner of the attic).

Would it be better to insulate the walls between the heated rooms and the attic space and continue to leave the window open?

Thanks, Walter

[Michael Daly]

In the long run, it will probably be cheaper to insulate more and prevent ice dams that way. Ice dams are a sign of insufficient insulation.

One way or the other you should look at fixing the insulation. Either enclosing and insulating the empty space or insulating the empty space to separate it from the heated space. Decide which is cheaper/easier. Take care of the venting while you're at it.

Mike

[m Ransley]

If you are in a cold climate zone 6-7 or less you want the attic at outside temps to prevent condensation in the attic from air infiltration. Insulate more and keep window open if venting is insufficient