I need to add insulate the ceilings of a 1937 house. The ceilings are nicely textured old plaster, so I don’t want to rip them out, or make big holes for blowing cellulose. Dropped ceiling is not really an option.
Would it be totally crazy to make some small holes in the ceiling and shoot some low-expanding canned foam (like Great Stuff for Windows and Doors) up there through long tubes? I know that’s not what this stuff was designed for, but it seems like a relatively neat, easy way to get at least a bit of R-value where there is none now.
Replies
yes, totally
Unlimited $$$$$ and unlimited TIME.......awwwwwh, WHY NOT?
The simple solution is not where our minds often drift......it is the ingenuity and complexity of the new idea this spurns us on .......even if it is sometimes insane.
But do keep a tally on the number of cans, the number of holes, and how the patches look! Better yet how about a jpg. of the colony of foam mushrooms in the attic!!!
Andy....just poking fun at your expense...for which I apologize. Seems as if I also have brainstormed phenomenal ideas....only to find out they were only brainfar s.
Try to rent an insulation blower....more R's, less $$$$, less time, no ceiling patch!
Respectfully..........................Iron Helix
I should have made clear that I'm not insulating the whole house - just 2 rooms. The first-floor den with the flat roof above and the textured plaster ceiling is only about 11 x 15, and the existing crack in the ceiling runs perpendicular to the joists, most of the length of the room, so it would be easy to poke some 1/4-inch holes in there for an acrylic tube and shoot the canned foam through that.
As for the attic ceiling, I just took another look and realized that the flat center portion is bigger than I had estimated -- 8 to 10 feet wide, and about 27 feet long, with two ceiling fixtures. I could remove the electrical boxes and use those two holes to blow cellulose --
BUT, BUT, blowing in cellulose (or fiberglass) would require installing a poly vapor barrier on top of the ceiling first, wouldn't it?
I could hire someone to spray in icynene foam, but that would cost more.
for cellulouse you ought not to need a vapor barrier, since the material is naturally resistant to air flow there is less chance that moisture can be carried into the space than there is now.
Icynene and other foams are difficult to blow into closed cavities due to their stickyness - it is quite hard to assure that all of the cavity is filled and your insulation won't be woth much unless the entire space is filled as a continuous membrane. Anything less will leave leaks.
Cells have been used for retrofitting for these two reasons.
Note that you will have to get access to each and every joist bay, so just one hole in the center may not do you any good.
One idea for a flat roof would be to drill in thru the exterior soffit, into each joist bay.
One idea for attic ceiling space is to remove the top course of shingles & sheathing to fill.
Norm
In the center of most of your rooms, there may or may not be a light fixture. Regardess, go to your local drywall supply house, buy the largest low profile faux plaster medalions that you can find.
Next find the center of each room and draw a circle 1" smaller than the medalion. Cut out the circle, remove the plaster and lath and you have an access hole to blow the insulation from. Once completed, patch the hole and cover with the medalion.
No one will ever know you insulated but you and the utility company.
Gabe
Gabe, I like your idea. Were you thinking I should use that hole for blown-in cellulose, or for my crazy spray foam idea? Cellulose would require laying down a vapor barrier first, wouldn't it?
As for access from above, I wouldn't be thinking so far out of the box if I had that simple option available. One room has a flat roof above it (and boy, does snow melt fast on that warm roof!), and the other room actually IS a finished attic. I should add that the room with the flat roof above it has a crack in the ceiling that needs repairing, which is what gave me the idea of creating small holes along the crack to poke a tube into.
Andy, in the finished attic room whats the flooring? Carpet? View ImageGo Jayhawks
The finished attic room has a floor of beautiful yellow pine. Why do you ask? The problem up there is ice dams; increasing the attic ventilation did not help, so I thought adding insulation above the ceiling might help.
If the attic is finished then the floor of the attic is part of the conditioned space. You don't want to insulate there.
You want to insulate the ceiling.
Yes, that's exactly what I was asking about - insulating the ceiling above the finished attic space.
Sorry, I thought you were trying to get insulation between two floors, was thinking you could go in from above but....
View ImageGo Jayhawks
The foam cans would be a waste of time and money so that's out of the equation.
You could blow in any one of the various insulations available today and they would all be about the same.
Closed cell sprayed in place polyurethane would be the best and would do the best job for the dollar.
It's also the only one that would double as a vb. Even cellulose dense packed isn't worth a plug nickel as a vb.
If you live in a cold enough climate to have snow on your roof, you would be well advised to skip the "save the plaster" stage and insulate properly ceiling and walls. The payback would be fast and the comfort worth the hassle.
Gabe
If your ceiling is under an attic, don't you have access?
If you're just insulating between an upstairs floor and your ceiling in the joist bays, using Great Stuff would be expensive, messy, difficult to control and you might end up having the equivalant of an inflated basketball doing a number on your ceiling.
Jules Quaver for President 2004
Andy,
Nifty idea but the greatstuff would be the wrong package. You are reading from a guy who has ruined 3 winter coats by spraying that stuff. It is the messiest stuff you'll ever use and the can package is the wrong format.
The first coat got ruined by my laying on my back under a VW bus insulating a secondary sleeve I wrapped around the heat tube from the engine heater ports. In Wisconsin the bus never had enough heat to defrost the windshield. The only way I got it to work was that insulation program and a clear plastic wall behind the front two seats. There I learned the upside down can spray problem.
You see the great stuff only sprays with the nozzle in the down position. Just like Whipped cream in the can. (Oh by the way... the propellant is not nitrous) Plus the cost at 3 bucks a can (possibly 2 to 3 square foot per can) is really up there.
There is a different package. Some building supply stores have 1/2 gallon vessels of this stuff with longer hoses etc. If you are insulating with that type of spray on foam, those suppliers would be the ticket. The box stores don't have it except in the single upside down cans.
Then again there are professionals who have the spray outfit to do it more completely.
You have already received some very good information but let me add one thing about GREAT STUFF. Read the can, it is a draft stop product not insulation. In the conditions you are stating it sounds like you have vaulted ceiling with not accessible attic space above. If you are attempting to insulate the rafter space it would be difficult as there is no interconnection between each one and you would have to seal every one. What a mess. I would look into some type of insulated sheating panels to apply to the roof system the reshingle.
Ice dams in your case may be from lack of insulation in the exterior walls and ballon framing which creates a pathway for heating. Check trying to stop the travel of heat from basement to attic through exterior walls.
If that is already done look closely into installing and ice-guard product under the shingles farther back up the roof from than the 24-inches inside the plan of the exterior walls. May also want to look at the conditions at the edge of the roof. I have found that gutter installation above the roof line extend will act as a catch for snow attempting to slide off the roof and therefore hold the snowpack in place which is the melted from underneath.