Insulation options for balloon-frame home
I own a 1908 2 storey balloon frame home that was recently damaged by fire. It was necessary to gut the basement and main floor. I had no previous knowledge of this type of construction and have sought to educate myself before the renovation progresses further. It was plaster/lathe construction, no insulation in the walls ( there is some cellulose attic insulation), wood siding original exterior, covered over now with vinyl siding also.
I would like to insulate the wall cavities before the interior drywall is installed, but everything I read confuses me further as to whether this is a good idea or not? The reason for not insulating seems to be to prevent moisture problems and wood rot from interior humidity migrating through the plaster walls…. the original airspace allowed the cavity to breathe and move the moist air upwards where it could be vented out through the attic….but now, I no longer have plaster/lathe interior walls, nor would the original exterior shell breathe as well since there is also vinyl siding on top of it… so does it make sense to add fibreglass batts and vapour barrier now, treating it like any new construction? Or perhaps spray foam if the cost is not too prohibitive? I have also learned blocking the sills between floors will be helpful if fire ever broke out again, to make it harder for the fire to travel upward with ease throughout the structure. Hearing from others who have dealt with this issue is most welcome! The property is in Ontario,Canada… winters can be harsh… summers can be hot and humid!
Thanks
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Replies
A Bit,
Briefly: Yes, you can insulate this house like any new house -- especially if the house is open to the studs.
Yes, you should install horizontal blocking in the stud bays to separate each floor.
No, the purpose of balloon framing was not to "move the moist air upwards where it could be vented out through the attic." You should always strive to limit air movement through wall cavities.
No, the vinyl siding won't interfere with "breathing." Vinyl siding is inherently well ventilated, so vinyl siding doesn't prevent the original sheathing and original siding from drying outward by diffusion.
Thank you so much for the quick response... very much appreciated! Final note will be the upstairs floor of the home was not gutted after the fire, so for now, will likely remain uninsulated.... unless I decide to have cellulose blown into the upstairs walls...thoughts as to whether this will be necessary or make sense? Heat rises... the upstairs has always been quite warm... my thought was more that insulating up there could make cooling the home more efficient in the summer months.
Insulation is almost always a benefit to both heating and cooling. If you have an open attic space, make sure you insulate in there too. Blown insulation is usually best there. If there is no insulation at all, THIS IS THE TIME FOR AIR SEALING! Don’t forget to air seal everything BEFORE you put the insulation in!
The horizontal blocking Martin mentioned is a type of fire stop. The open vertical wall cavities in Balloon framed structures allow fire to spread. Horizontal blocking helps to limit this. This is important.
Bill
With balloon framed house dense packing (cellulose or fiberglass) is your friend.
Filling the 2nd story walls will make a huge difference in comfort. This is the time to do it.
If your 1st walls are open, the easiest is to put in the fire blocking for the 2nd floor, drill 2" hole in it and blow in the insulation. A lot of times the walls are also missing blocking in the attic, you want to get these also sealed up as well. You can also fill from the attic if you can't get it all from the 1st floor.
Its also probably best to dense pack the main floor walls as well to get a better air seal. The original wood siding leaks air like a sieve, putting standard batts into the wall without air sealing will do little for energy use. If dense packing is not an option, it would be best to get 1.5" of closed cell foam over the wood siding to seal it up then install batts.
Very important to have somebody check the flashing around your windows and doors. These are usually non existent/sub par in older homes. With open stud cavities this is not an issue, but once insulated, water leaks there are a recipe for soggy moldy insulation.
Also don't forget to put in blocking at the end of your floor joist/ceiling bays. This is another big source of air leaks in these houses.
I was amazed at the difference that dense packing and air sealing made on a 1900's balloon framed house.
I, too, have a balloon frame older home. What is the best way to do the air sealing before the dense packing?