Is it better to insulate the inside of a house or outside during renovations? And which insulation is best?
We bought a 3 bedroom house on a slab 5 years ago! We soon realized that the insulation is little to non existent! The attic has batt insulation but the walls of the attic have nothing! The aluminum siding is nailed right to the studs! When it's cold outside an I drill holes to install a Molly to hang pictures etc. Anywhere in the house I can feel cold air coming from the hole! We have to use space heaters in the bedrooms an Living room! In the summer the AC runs more then it should have to! So my question is what type of insulation should I install? An where? We're going to be removing the siding an replacing it so I'll have access to the entire outside of the house! I'm not trying to spend a fortune but we plan on spending the remainder of our lives here so it needs to be done right! Any suggestions would be greatly appreciated! Thanks
The best way to insulate older homes depends on several things, including how extensive the demolition you are doing, whether you are focusing the demolition on the interior or the exterior. The best job possible would be from the outside, as it is the best way to create a seamless thermal barrier of insulation, as well as install an air barrier. Since you are removing the siding anyway that would be your best bet, assuming you have enough space on either side so you meet the setbacks from adjoining properties. Are you in a densely packed urban core with limited space or are you able to expand the exterior dimensions of the house as you see fit?. I'll assume for now you have space.
If you are taking the exterior walls back to the sheathing, I would first suggest a peel and stick exterior air barrier membrane, that will stop your air leaks which are a bit part of the problem. From there you can install exterior insulation, and new siding. So my suggestion would be to check over the following pages that cover these topics, and once you have let us know if you have more questions, but also tell us what climate zone you are in, or city, state, province, as the climate you live in largely decides the best method and amount of insulation.
The easiest way to install exterior insulation on old homes
Choosing the right insulation
How to install a peel and stick air barrier membrane
How to install siding so walls can dry