[bcemail]

’m working on a two rooms that were added on to the end of our house (included a diagram of 1 of 2, they are basically mirror images). We have a gambrel roof, and the rooms go all the way up to the rafters (there is drywall, not sure about insulation) and then near the side part of the roof there are vertical walls. The ceiling at the highest is about 12’ and from the side to side it’s also about 12’. The first room has the gable vent still there on the interior wall.

In order to get this first room to be usable, conditioned space I’m considering putting in a new ceiling to match the rest of the rooms on this level. I would just leave the drywall up on the rafters, wasn't sure if insulation there would matter. This would also leave the gable vent up in unconditioned space, and I could eventually duct that to the outside, if needed.

I was considering attaching a rim joist to the walls running around the perimeter of the room (I don’t know if rim joist is the right term here). Then I would be running joists across the room. In between the joists I would put batt insulation, recessed lighting or an overhead fixture etc., and maybe even rigid insulation on the bottom of the joists (saw this suggested on another site). Then attaching my drywall to the joists or furring strips underneath. This would mean I only have to put drywall on the ceiling (or maybe even a drop ceiling), not ripping off any walls. I'm going to check the exterior wall for insulation, and if there's none I was going to cut some holes and use blown in.

So, finally for my questions…

Does this make sense? What would be recommended lumber size? From what I found in code tables, I was thinking 2x6 for the 12' long joists, but wasn’t sure what size the rim joist should be. Couldn’t figure out how to look this up, since I don’t really know how to refer to it. Would 2x4 be enough? I would use lag screws to attach to the studs.

Should the joists sit on top of the rim joist or attach to the face? If I put the joists on top of the rim joist, I’m trying to figure out how to cover up the rim joist. Should I try and drop the level of the ceiling the height of the rim joist so that the drywall can run all the way to the wall? If I attach to the face, I’m guessing I would use joist hangers, but wasn’t sure if the drywall could just butt up against the bottom of the hangers.

Please let me know any other thoughts or suggestions! Thanks!

 

[ClarenceBauer]

You could use a metal grid system like USG Grid system for sheet rock ceilings.
It would be less weight & maybe faster than wood.

 

[bcemail]

You could use a metal grid system like USG Grid system for sheet rock ceilings.
It would be less weight & maybe faster than wood.

Didn't know about those but I bet it would be easier. Trying to find a site that has actual costs so I can figure out what it would cost. Armstrong also has a system and some really nice TnG planks that look nice but are probably too much $$. Thanks!

 

[Marson]

The USG suspended ceiling would probably be easier, but if you want to add insulation that may be a problem.



If you go with wood, what you are calling a "rim joist" is what most carpenters would call a "ledger". You would make it the same size as your ceiling joists, and butt the joists into the ledger. Use some joist hangers and you will be good to go.

 

[Nealtw]

Ledger is the word you are looking for.
There are a few things.

Are the rooms back to back on the same wall?

If you are making the attic cold space good ventilation will have to be figured out some of the upper dry and maybe all of it should be removed.

The new ceiling would have to be air tight from the house and light fixtures want to be IR rated. You would do blown in above the ceiling Or batts above the ceiling.

Have you opened the wall to see how it is constructed? The one you are thinking about the ledger.

 

[bcemail]

Ledger is the word you are looking for.
There are a few things.

Are the rooms back to back on the same wall?

If you are making the attic cold space good ventilation will have to be figured out some of the upper dry and maybe all of it should be removed.

The new ceiling would have to be air tight from the house and light fixtures want to be IR rated. You would do blown in above the ceiling Or batts above the ceiling.

Have you opened the wall to see how it is constructed? The one you are thinking about the ledger.

Ah, ledger, thanks!

Yes, the rooms are back to back. In my diagram the second room is through the wall on the right. Is it OK to put a ledger on both sides of the wall?

I guess it would be attic space, which it sort of is now. I wasn't sure if I could insulate the new ceiling and then have drywall and possibly insulation above, or if it would trap air or moisture or something. I'm fine with pulling down the drywall on the ceiling, was mostly dreading having to try and put new drywall up there.

Once I have drywall in, it would be airtight from the above space, right? I could also add foam around any gaps, if that would help (I'm assuming no other area of the house has this, as an air pressure test we had before insulating the attic showed plenty of leaks). I guess a drop ceiling might not provide that, never thought about that.

Did you mean IC lights, not IR? I can then just blow insulation or lay batts right on top of them?

I would be running the ledger around all 4 walls to get a surface to attach joists to, unless there's a better way. I will open up the walls in order to see how they are built, but wanted to have a plan first so I could just cut some holes to look in, and not trash the drywall completely.

Thanks!!

 

[Nealtw]

Ah, ledger, thanks!

Yes, the rooms are back to back. In my diagram the second room is through the wall on the right. Is it OK to put a ledger on both sides of the wall?

I guess it would be attic space, which it sort of is now. I wasn't sure if I could insulate the new ceiling and then have drywall and possibly insulation above, or if it would trap air or moisture or something. I'm fine with pulling down the drywall on the ceiling, was mostly dreading having to try and put new drywall up there.

Once I have drywall in, it would be airtight from the above space, right? I could also add foam around any gaps, if that would help (I'm assuming no other area of the house has this, as an air pressure test we had before insulating the attic showed plenty of leaks). I guess a drop ceiling might not provide that, never thought about that.

Did you mean IC lights, not IR? I can then just blow insulation or lay batts right on top of them?

I would be running the ledger around all 4 walls to get a surface to attach joists to, unless there's a better way. I will open up the walls in order to see how they are built, but wanted to have a plan first so I could just cut some holes to look in, and not trash the drywall completely.

Thanks!!

I don't have any experience with this roof so my questions are real and I don't have the answers
So first I looked at insulation and venting.

If the red arrows are room heat ( warn moist and dirty ) if allowed to get to the attic, the air cools the moisture condenses and deposits dirt and moisture which is food for mold.

Pink is the heat that does get passed insulation and can cause ice damming
Blue is the path of cool air from low to high in an uninsulated space.
Black would be where you want solid blocking for air flow.
So beside adding a ledger you would want to open walls and add what is called fire stop (Air Stop) in the walls between room and attic. This is normally the double top plate of the wall on a normal house.

 

[Nealtw]

Then the big question is how much weight can you put on non bearing walls.

The outside gable end would be bearing and the outside roof line would be bearing, what else have foundation under it?

 

[bcemail]

I don't have any experience with this roof so my questions are real and I don't have the answers
So first I looked at insulation and venting.

If the red arrows are room heat ( warn moist and dirty ) if allowed to get to the attic, the air cools the moisture condenses and deposits dirt and moisture which is food for mold.

Pink is the heat that does get passed insulation and can cause ice damming
Blue is the path of cool air from low to high in an uninsulated space.
Black would be where you want solid blocking for air flow.
So beside adding a ledger you would want to open walls and add what is called fire stop (Air Stop) in the walls between room and attic. This is normally the double top plate of the wall on a normal house.

Thanks for the diagram. I'm guessing that if the top is drywalled or insulated it would trap the air I want to be able to vent out? I will do everything to make the living area air tight. There are some gaps on the side wall that need to be sealed up as well.

For putting a fire block in, is there a reason the top plate isn't enough? I see people putting a secund 2x4 in below the top plate but I thought a 2x is enough to seal? I'm guessing my 2x studs go all the way up 12' so I would just fire block around the area of my ledger? Then adding some fire foam or cash if needed to fill the gaps. Thanks!

 

[bcemail]

Then the big question is how much weight can you put on non bearing walls.

The outside gable end would be bearing and the outside roof line would be bearing, what else have foundation under it?

Would interior walls normally be able to hold a ceiling? I was assuming it would be too much

We are going to have an engineer come and look at the foundation under the first floor. The secund story used to be a deck that was then enclosed. And I'm sure it was done poorly. And I'm guessing the foundation isn't enough. But it hasn't fallen off yet which is something. Trying to do most of this as diy so that we can afford any structural fixes needed.

Thanks!

 

[Nealtw]

Thanks for the diagram. I'm guessing that if the top is drywalled or insulated it would trap the air I want to be able to vent out? I will do everything to make the living area air tight. There are some gaps on the side wall that need to be sealed up as well.

For putting a fire block in, is there a reason the top plate isn't enough? I see people putting a secund 2x4 in below the top plate but I thought a 2x is enough to seal? I'm guessing my 2x studs go all the way up 12' so I would just fire block around the area of my ledger? Then adding some fire foam or cash if needed to fill the gaps. Thanks!

Yes a sealed 2x block between the studs would do that.

If there is no insulation behind the upper drywall, you might just remove a lower and higher strip so air can flow in and out. But it would be bad news if you ever have a mold problem

The space between your outer wall and the roof might be an insulation problem. If the house was built with out insulation then you won't have the blocking there either.

See the solid block between the joists under the wall.

 

[Nealtw]

Would interior walls normally be able to hold a ceiling? I was assuming it would be too much

We are going to have an engineer come and look at the foundation under the first floor. The secund story used to be a deck that was then enclosed. And I'm sure it was done poorly. And I'm guessing the foundation isn't enough. But it hasn't fallen off yet which is something. Trying to do most of this as diy so that we can afford any structural fixes needed.

Thanks!

Normally the ceiling is sitting on a load bearing wall. We see some house that don't but we don't know that some engineer type didn't do a load calculation to say it will work. So just because we see some doesn't make it right.

What are the dimensions of these rooms