Insulating a stairway

[FSNut01]

I'm not sure if this is the right place for this or not but here goes.

We have built a 30x40 gambrel style barn. The main floor has radiant heat and will be used for 2 cars, lawn equipment & a small shop area. The attic space will be used for storage and a game room. The main floor has a 10' ceiling and the attic has an 8' ceiling. I am trying to finish up the framing at the stairs so that I can start insulating. The attic will not be insulated at this point so I need to isolate it from the main floor. I framed the opening around the top of the stairs in the attic and made provisions for a door at the top of the stairs. My original plan was to hang OSB around the inside of the framing, insulate the stud walls and then skin the outside of the framing in the attic. I am now having second thoughts and think it might be better if I frame out a sloped ceiling over the stairs instead. My only reservation on this idea is that we may be carrying large bulky things up the stairs and the big open area would provide more room to maneuver.

Does anyone have any thoughts or suggestions? Leaving it the way it is seems like a lot of wasted space above the stairs. How much heat loss will I have up into the 2 story opening?

Here are some photos to help visualize what I'm talking about.

This is looking at the stairs from the main floor:

Looking up the stairs from the landing:

Looking at the area I need to insulate from the top of the stairs:

In case anyone is wondering why the side walls are split into 2 sections, the builder built a low wall on each side of the stair opening and I just continued it to the joists rather than rip out the low walls.

 

[Tim The Tool Man]

I would just go ahead with your initial plan. Yes some heat will migrate up the stairwell but it will have no place to go. You won't notice much if any loss but if you are concerned about that warm air just hovering up there then throw a ceiling fan up there to blow it back down...

I think I would value the ability to move large objects up the stairwell more than knowing there is a bubble of warm air in that open space.

Now if you don't put a door up there then that's a different story...

 

[green.bubbly]

If your question is whether or not to leave the stair ceiling flat or sloped then either way would be fine as far as heating goes. Leaving it flat will only add a few extra cubic feet of space. Bulky items will at some point have to fit through the stair opening so whether your ceiling is high and flat or sloped does not matter.

I like your stair design by the way. You have any pics from under the stairs? I would like to see how it was framed to attach the risers and steps.

 

[NUTTSGT]

I don't think you'll notice much heat loss as it'll only be a small area. If you do decide to close it in, you could add some storage space into the area above the stairs that you close off.

Basically make a cabinet into the wall, I'd start it at the wall split and reframe that area in to form a box. You could run a couple of 2x across to make floor joist and some 3/4" OSB for the floor. This was brought up in a stairway thread from Bull.

 

[FSNut01]

I like your stair design by the way. You have any pics from under the stairs? I would like to see how it was framed to attach the risers and steps.

I don't have any pictures of under the stairs but I'll take a couple tonight and post them up. The stairs are pre-built from the building materials supplier the builder used. They are built like interior finished stairs would be, routed grooves in the sides with wedges and glue to hold them in place. They are good quality, solid and will get stained and sealed eventually.

If you do decide to close it in, you could add some storage space into the area above the stairs that you close off.

Basically make a cabinet into the wall, I'd start it at the wall split and reframe that area in to form a box. You could run a couple of 2x across to make floor joist and some 3/4" OSB for the floor.

Hmm... I like that idea. I hate the thought of wasting so much space. And it would end up easier to reach as well. I have a piece of 3/4" OSB left over that would fit perfectly too.

 

[green.bubbly]

I don't have any pictures of under the stairs but I'll take a couple tonight and post them up. The stairs are pre-built from the building materials supplier the builder used. They are built like interior finished stairs would be, routed grooves in the sides with wedges and glue to hold them in place. They are good quality, solid and will get stained and sealed eventually.

Thanks, that is kind of what I was wanting to see. I never thought about routing grooves in the stringers.

 

[FSNut01]

green.bubbly, here's a couple shots of under the stairs. Let me know if you want to see anything else.

 

[FSNut01]

I ended up framing a sloped ceiling partway up the stairs, about halfway. I feel better gaining the additional storage space above it and it will make it much easier to attach the OSB to the walls and ceiling. Here's what I did:

 

[green.bubbly]

That looks good. Having a flat ceiling would have served no purpose other than to waste space. Thanks for the pics of the bottom of the stairs. That is what I wanted to see. Gave me some ideas for the stairs I am about to build.