03:21PM | 07/12/04
Member Since: 08/25/01
5 lifetime posts

In a house that still has some old wiring, (knob and tube) is it safe to have insulation blown in?



03:49PM | 07/12/04
Member Since: 07/01/03
550 lifetime posts
I answered this last year on the Fix-It For'em at

To quote myself: Adding insulation in walls with K&T electric is acceptable PROVIDED the wiring is operating at or below its rated capacity. If you look in the fuse box and see 30 amp plus fuses the circuits the answer is no. If the circuits are properly fused at 15 to 20 amps, the wiring (usually 12/2) is operating within its rating and will not generate hazardous heat. The insulation itself does not support combustion and has ammonium sulfate which acts to supress compustion. Still, you should not install it where the possibility of a hot over loaded circuit exists.

Keep in mind too, that adding insulation will make later wire routing more difficult assuming you want to upgrade to modern sheathed electrical cable wiring.

End of quote

One other point, insulation will make replacement of plaster walls more difficult, or at least will incerase the amount of material to dispose of. If you think you may want to rewire, upgrade plumbing or replace plaster walls in the next few years, its best to do a demolition and replace with drywall. In that case you can insulate while the walls are open.


Post a reply as Anonymous

Photo must be in JPG, GIF or PNG format and less than 5MB.


type the code from the image


Post_new_button or Login_button

Colorful, useful, and fun, these tire planters form the foundation for a delightful container garden. Just spray-paint old... Reused steel windows create an eye-catching splashguard in this walk-in shower. The vintage factory windows bring an inter... A galvanized steel tub is a surprising but charming fixture in this bright and breezy screened patio. It's perfect for was... If you're not crazy about the idea of commingling plants and pool, this modern variation may be more to your liking. The s... Yes, a freestanding garage can become its own tiny house. Artist Michelle de la Vega has all the comforts of a modern resi... If you lack plumbing skills but have a good sturdy tree, here's the easiest outdoor shower solution of all: Simply attach... Pursue what's known as the stack effect. To achieve it, open the windows on both the upper and lower floors, and as warm a... How do you like this smart use for an old bottle? Clamp an empty wine bottle to a fence or wall near your outdoor deck or ... Simple and striking, a couple of pieces of "lovingly used" furniture creates a special kind of charm. A weathered chair fo... Twine lanterns add pops of crafty—but sophisticated—flair to any outdoor setting. Wrap glue-soaked twine around a balloon ... When securely fastened to a tree or the ceiling of a porch, a pallet and some cushioning make the ideal place to lounge. V... Incorporate nature into your lighting scheme by securing a dead tree in a concrete mold and draping your pendant lamp from... For the cost of a can of exterior paint , you can totally transform your porch. Paint the floor a hue that complements yo... In this urban apartment, a standard-issue patio became a serene and green perch by replacing the typical concrete with gro... This garden shed has been decked out to the nines. Designer Orla Kiely created the intimate home for a flower trade show, ...
Newsletter_icon Google_plus Facebook Twitter Pinterest Youtube Rss_icon