Shop Insulation

[Charlie Watson]

Hi all. I’m in the process of converting my attached 3 car garage to a wood shop. Prep is underway. I’m bringing in the electrician Monday to quote on a new sub-panel and new circuits, the epoxy floor goes down at the end of February and in the meantime I’ll be painting. I’m also going to bring in an HVAC guy to give me some options on conditioning the air. I’m in San Diego so we don’t get much in temperature extremes so I don’t need anything too major. The one problem I have is that the builder didn't insulate the walls before being finished and I sure would like them to be insulated. Is there anyway to retrofit insulation without tearing the walls down (is blown in insulation in the walls an option?) Thanks all, I appreciate your thoughts.

[Ken Fitzgerald]

Charlie, Welcome to the Creek!

There are several options for insulating without removing the wall coverings...there are foam and blown-in insulations available. I'll let others with more expertise than I respond in detail. I live in central Idaho and I insulated the walls of my shop to R-19 and the ceiling to R-30. I don't regret it. We tapped the gas line for our house after the meter and we didn't see a significant rise in natural gas costs. It pays in the summer too! I have seen 20ºF difference between our summer heat in excess of 100ºF and the temperature in my shop.

[Steve Rozmiarek]

Charlie, you can blow cellulose into the wall cavities. Cut a couple holes, one for the hose, one for the air to escape in each stud bay and fill it up. Or you can remove a 4" strip of drywall from the top of the wall and do the same thing. It won't be perfect, and it will settle a bit, but much better. If you take a strip of drywall down, you can fill the top few inches with fiberglass, and be filled to the top.

One more thing, is the ceiling insulated? The walls won't matter if the ceiling isn't done right.

[Charlie Watson]

Thanks for the input, glad to hear there are some viable options. I'll need to do the ceiling too but that's a bit more accessible so shouldn't be a problem.

[Ray Newman]

My Standard Answer: If you are going to stay in your house and not move, insulate to the maximum extent possible. It will be more efficient and soon pay for the extra insulation cost. Same with energy efficient windows.

Energy costs are not going to decrease….

[Phil Thien]

It is my understanding that blow-in cellulose is actually really good insulation in that it also stops air migration (which I do not think fiberglass really does). It is just much better than I had originally thought when I first researched the stuff.

I had a friend whose dad did spray in cellulose from the exterior when I was a kid. He actually made big bungs to plug the holes when he was done, and he left the bungs in for a year. He then removed them, and topped-of the bays (it settles) using a tool he had come up with himself. He then replaced the gungs again and checked the next season. He didn't see much more settling, so he sealed-up the house.

None of those old houses had any insulation, I know he saved a ton on his heating bills after that. The other thing I noticed about their house was just how quiet it was inside after that. Less outdoor noise getting in. Although he also replaced his storms and that may have had a lot to do with it I suppose.

[Steve Rozmiarek]

Phil, you are right about the noise reduction. Seems like I do a lot of insulation for some reason, I'm on building 7 now... It's fun to hear, or actually feel the silence after the insulation goes in. Completely changes the space.