Any ill-effect on the house if without attic insulation?
 

I have a ton of projects going on in my newly-bought house. It had rat problem and although rats are now gone but they have left droppings, urine all over on the attic batts. I paid the insulation company to remove ALL the attic insulation. Now I'd like to plan for putting R38 insulation in late December when I have finished all the work up in the attic like the 30 something recess lighting and some home security system wiring. It's a lot easier to do these jobs without insulation in the attic.

I would just like to know what is the downside/ill-effect from me heating a single-story ranch house without any attic insulation. I live in the San Francisco Bay Area and typical temperature in December is 42F at night and 55F in the day. I am worrying about the moisture from the warm rooms will condense on the cold surface in the attic and create problems. Or is it that the only ill-effect is paying extra money for the heating? Thanks!

The expense is the worst thing probably.

Fiberglass insulation is not a sealant or sealer of any kind.

I think R-30 is all that is required in your area.

Andy.

"I am worrying about the moisture from the warm rooms will condense on the cold surface in the attic and create problems." -----
the f.g. insulation won't hardly make a difference: http://www.buildingscience.com/docum...bout-diffusion

You have an opportunity here that is quite rare! Now is the time to air-seal the attic: http://www.google.com/url?sa=t&sourc...O842EQ&cad=rja

http://www.google.com/url?sa=t&sourc...wWATQw&cad=rja

http://www.greenbuildingadvisor.com/...stop-air-leaks

Gary

Thanks a lot Gary! Actually the sealing thing is exactly what I am reading into right now at this moment. Last night while working up there in the attic, with the lights in my rooms on, I found so many cracks that leaks light into the dark attic. (i.e. around the kitchen vent, around all those recessed lights, all around my chimney which is located at the center of my house, etc.) I am going to seal all those up soon. It is truly an amazing opportunity to do. With the insulation on it's impossible to spot the cracks.

Just $$$ going up through the attic is all.

Wow at those temps who needs to heat :) That's t-shirt weather in minnesota!

That's what I was thinking!! We keep our house at 55! :laughing:

:eek: whow! That's too cold. You guys have strong bodies.:yes: I can't. I have to keep it at 70F.

"With the insulation on it's impossible to spot the cracks." ----- not really! That's what fiberglass is best at: http://www.finehomebuilding.com/PDF/Free/021105092.pdf

Well, that may not apply to you, until after you insulate. Have to take my jabs at f.g. when/where I can, it gets under my skin everytime I use it, starting about 37 years ago. Still need a few more....lol.... ah- another: http://www.diychatroom.com/f98/bigge...ulation-90438/

Gary

Yes, there is absolutely a risk for moisture related problems.

Living in a home creates many sources of moisture, water vapor. If the living space is at a higher RH (relative humidity), and the ceiling is colder than the dewpoint, you will have condensation on the warm side of your ceiling.

The more moisture you have, the greater the condensation problem.

I know of a bathroom that had no ceiling insulation and when the outside temperatures fell, the warm water vapor basically created large water droplets that dripped back down into the bathroom.

With enough attic insulation, the dewpoint temperature is not reached on the drywall itself. However, most types of insulation will not stop water vapor due to diffusion. So ultimately, air-sealing your attic will keep you from having water vapor condensing on the underside of your roof decking and causing further problems.

OK, that's the building science part, now the economic part.

Yes, you will have higher heating bills from the situation you currently have in place.

That is part of that new interior rain effect...:eek:

Who would you call for a job such as air sealing an attic? i need soffit vents in the attic and roof exhaust vents as well? a regular contractor or a roofing company?

An exterior construction contractor with a concentration in building science is probably your best bet to handle all of the above.