Quote:
Originally Posted by fsstnotch
Ok, last December I bought a new house(new to me). Well, so far it has been great except one thing. It was built around 1900 so it has some serious insulation issues! I have put $2k in propane into the house since Early Jan. Well, when I get home I was planning to insulate the exterior walls using the blow in type and also add a bunch to the attic.
Ok, now my question. When we had our home inspection, the inspector said it looked like the whole house had been rewired with updated wiring except one room on the second floor which still had knob and tube present. My understanding is that knob and tube gets really hot and could cause a fire if it were to have insulation put on it. Is there a way to determine if knob and tube is present and in use without ripping all the walls out of the house?
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Some great advice here!
My understanding is that the,
"knob and tube gets really hot and could cause a fire if it were to have insulation put on it" is true. Loose insulation is prohibited by the National Electrical Code because of that. Sheet foam is allowed but requires an open wall for installation. Most communities at least follow the NEC or are even more stringent.
My suggested, more drastic, solution for older homes, is to remove the old plaster, redo mechanicals and replace with new drywall. But then drywall-plaster is what I used to do for a living.
This "new wall" can sometimes be 95% done allowing borders of stable plaster to remain under good woodwork and in corners by only adding new drywall to within a few inches of corners and woodwork. Continue by reinforcing the nice flat drywall/plaster seam with common drywall tape and a little compound. It can be done by yourself, sometimes easier one or a few rooms at a time. It's not hard to do; messy maybe. Alternatively, it is also easier to find a reasonably priced contractor when local building is in a depressed economy, perhaps now or soon anyway.
Since you are looking to increase heating efficiency, there is one other thing I should mention. An important principle, brought up by
trularin, is the vapor barrier. What tends to happen in modern
well sealed homes is that vapor given off by cooking, showers, mopping and even respiration has no where to escape. I read once that it is about 4 gallons a day for a family of four, some info put out by a window company that was starting to get window damage claims regarding condensation.
As a contractor, during repairs caused by excessive condensation, I also ran into extreme situations where the homeowner purposely set an automatic furnace humidifier too high or vented a clothes dryer inside the house. Older homes often leak so much dry, cold air from outside that they self-vent ...but new-found efficiency may have this too much humidity caveat. A well sealed modern home will often humidify itself and sometimes even require and air-to-air exchanger to limit the effect.
By placing a vapor barrier on the inside of a wall or ceiling (right under the wallboard), as tru says, it will prevent rotting moisture accumulation in the cavity. Although the cavity moisture can't always be seen, it is accumulated there just like on the window glass (especially single pane) where it is stopped from soaking through and can easily be seen. I've noticed that the vapor barrier is sometimes forgotten, especially when people do their own remodelling.
I recommend 6 mil polyethylene or a vapor barrier paint if the wall is not opened. Some surfaces in older homes have several coats of
oil base paint which is actually a pretty good natural vapor barrier as opposed to most newer latex paints.
Some extremely warm humid areas of the country need the vapor barrier on the exterior, right under the siding. Humidity always travels towards the coolness and an air conditioned house in Florida has the opposite problem than a house in Pennsylvania, Michigan or North Dakota.
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http://www.doityourself.com/stry/vaporbarriers )
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