What can I do to upgrade wall insullation?

October 19, 2007 10:47 AM

There's a certificate in my house attesting that the walls, ceilings and floors were insulated with cellulose in 1997. The walls and floors were insulated "to capacity" (whatever that means). The walls are still cold in the winter and I think they are sucking warmth out of the house. Is there anything else that can be done 10 years later other than demolition? Have techniques or materials changed since then?
posted by andreap to home & garden (8 comments total)

It's settled. Have more blown in (or blown in fiberglass blown in) and then have fiberglass batt's intalled at the tops of the walls to help prevent thermal settling.
posted by Pollomacho at 11:00 AM on October 19, 2007

It sounds like insulation has been done. But any drafts in the house will nullify the insulation amount, so you might concern yourself with that. Windows, doors, fireplace flu, etc need to be checked. I'm not a HVAC guy, but just went through all this last winter on our place.
posted by artdrectr at 11:12 AM on October 19, 2007

You probably have a wood frame house where the spaces between the studs were filled with blow-in foam insulation. Your walls might never actually be warm to the touch no matter how much insulation you put in there--the real question is: How much energy do you use to heat your home to a point where it's comfortable? Does your home experience broad, rapid temperature changes in the interior if you're not running some sort of heating or air conditioning? If you are feeling cold, the first thing to check might be the tightness of seals on your doors and windows, and whether your windows are dual-glazed or not. Then worry about the walls. "My walls are cold" is not really the metric you want to go by for energy efficiency.

If you do end up needing more insulation, you may be able to upgrade to a different kind (I think the most efficient would be rigid foam, but I don't really know how much better that would be than blow-in). For that, they'd just need to remove the drywall on the interior walls and remove the existing insulation, and then re-insulate.

The only other way to do it is to thicken your walls. If you need to do that, you can always "furr" in the walls a couple inches, but that will rob you of floor space. But then, if you demolished and rebuilt the exact same floor plan, you'd have the same problem.

Anyway, I'd check the windows first--they're usually the weak points in a thermal envelope. Many local power companies will offer a service where they'll come out and investigate ways that your home could be more energy efficient, so you could check with your utility to see if they do that.
posted by LionIndex at 11:16 AM on October 19, 2007

Get an energy audit -- your local utility probably offers this for free. They'll do an infrared analysis among other things that will show you where the cold spots are.

The cellulose is NOT sucking warmth away, it's just not doing as good a job as it should at keeping it in. Any type of insulation is basically creating a maze of air pockets between you and the outside -- it's the air pockets that do the actual insulating, because the air is unable to circulate. If you have cold walls, that just means there's too much air circulating for one reason or another.

I would also look at whether you had adequate caulking at the top and bottom of walls and what type of weather barrier/house wrap you have under your siding.

In any case, your walls will feel cold to the touch in winter no matter how well they're insulated.

Demolition? That's a bit drastic. There are millions of people living in houses built before the 20th century that have been adequately brought up to modern standards. The house I grew up in didn't have any insulation in the walls until we bought it in the 1970s.
posted by dhartung at 11:18 AM on October 19, 2007

seconding (based on the available info) the settling explanation - from what I understand blown cellulose often needs to be topped up a few years after installation. see also this interesting post about it:
link
posted by aquafiend at 11:54 AM on October 19, 2007

You might want to consider weatherizing the exterior. Have the siding stripped and then put rigid foam board on the entire exterior. Seal around all windows then put new vinyl siding on.
posted by JJ86 at 12:40 PM on October 19, 2007

As stated above, you need to top off your insulation. Also wall "feeling cold" is not a good indicator of the amount of energy you are using to heat your house.
posted by oneirodynia at 12:50 PM on October 19, 2007

If by 'demolition' you mean 'Pull out the walls, put in fibreglass batting and hang sheetrock over it', and not 'Tear the house down', then (IMO) it's worth considering - When they blew cellulose into my house previously, the installers actually told me it was only going to last about (wait for it...) ten years before it would settle to the point of being useless.

Taking out the exsisting interior walls and installing fiberglass batting is labor intensive and annoying, but easy, and quite DIYable if you've got the time. Putting up new sheetrock is tricky. Get somebody to help you for the first room or two if you go that route.
posted by Orb2069 at 2:01 PM on October 19, 2007