Insulating An Attic

I want to finish my attic space and make it conditioned living space. There is already ducting to tap into and a few outlets. There is currently R21 fiberglass between the downstairs living space and the attic floor, with the paper barrier down. I think code for my area is R38 for ceilings, which is virtually impossible with my thin ceiling rafters. I am not a fan of spray foam, nor could I afford it, so I'd like to use the several hundred dollars worth of R21 I already have. Since the floor of the attic has 6" insulation already, would it cause moisture problems by finishing and insulating the ceiling? I'm currently getting a slight ice dam issue with it being unfinished space so I'd like to kill 2 birds with one stone, without bringing moisture problems into the mix. Any advice would be appreciated.

 

Hi Dr and welcome to the forum,
Converting an attic to living space is a bit difficult and something that needs to either stay as ventilated space of move that ventilation up to just below the roof deck. I guess one more option is to eliminate the ventilation all together, but all three have guidelines and moisture is a primary concern.

Electrical, plumbing, egress, and building permits all need to be reviewed and in most cases those departments can help with what is needed.

What size are your current floor joists, the ceiling below? A determination as to how strong they need to be will need to be done.

Do you currently have stairs going up there?

As for the r-38 that will be needed as you can't add the current attic floor insulation to some additional in the rafters to meet that number.

What do you currently have for ventilation, soffit and gable vent, maybe a ridge vent?
How much head room will you have when finished?
How old is the home?

Bud

 

All great questions!
Good job Bud!
No one knows your location, because it's not in you profile, which is a huge issue with questions like this.
There's been hundreds of post on this one subject on this and any DIY site.
People see all that "wasted" space and want to add on.
There's just far more to it then slapping something up there as mentioned.

 

Hi Bud,

Here are a couple pictures:
https://drive.google.com/open?id=1Fl...EtvT-ZvAgNHbMw
https://drive.google.com/open?id=1UY...nTflc3hrc2s-Xl

The house is shaped like a T and there are 2 separate areas of attic. The top part of the T is where the stairs come up from and it's gable vented, no soffit on that side. I want to seal that area and leave it unfinished for storage. The area in the pictures is what I want to finish and it's soffit and ridge vented. The previous owner has insulation stuffed down on the soffit so it can't breathe. I think that's why the ice dams are happening, from heat rising into the attic and meeting the frigid roof. For the ceiling below, it is double reinforced so its 12 on center with 2x8s with a large beam down the center of the room (4 2x6's bolted together). I made sure that was done in case I tried to finish the attic.

No matter what I want to avoid mold like the plague that it is. This house had mold issues in the basement when I purchased it, which has been remedied. I don't want to go there again.

 

I am in Ohio FYI, forgot to mention that.

 

Sure looks like there's no where near enough head room to even make a room up there.
https://www.revisor.mn.gov/rules/?id...305&format=pdf

 

Well, you definitely get some cold weather there so the limited space for insulation will create problems. Ventilation serves two purposes, remove the heat that is causing the ice dams and removing any moisture vapor that seeps up right through the drywall as well as leaks. That moisture vapor will lead to mold.

Head room as Joe mentioned and a host of other limitations and basically that space needs to remain as an attic and be insulated and air sealed at the floor level to prevent those ice dams. At least that work will have a positive benefit and be an asset to the house. Converting to a non-permitted makeshift living space just won't work well and it becomes a liability that future buyers and inspectors will not like.

Bud

 

I've looked up my state codes and they're saying 7 ft wide floor space minimum, which mine is over 11 ft wide if knee walls were installed. The ceiling height on the ridge would be right on the limit of 7.5' after sheet rock. The code doesn't specify what % of the floor needs to meet that 7.5' height. But I will say every contractor that has went through the attic said it would be a cool space to finish, and I've had at least a dozen up there. I'll need to dig through more fire code to see what's possible and maybe have a licensed contractor come take a look.

Thanks for the help folks.