# Insulating Gambrel Roof (ceiling)



## Victoria-nola (Aug 17, 2015)

Hello, and thank you for being here. We created a cabin on our property for my ailing mother by purchasing (mom is making payments on) a 14'x32' premade portable shed from a Derksen seller, then customizing it by installing a (double-paned) picture window and building out the interior (a friend of ours did the work for friendly pay, we assisted). It's very cute but low budget. We insulated the walls during construction, which are then panelled with a textured 3/8" plywood (looks like beadboard). The roof is Gambrel, with metal sheathing on the exterior and felt underlayment, OSB sheathing. The interior was primered and painted. The interior members are 2x4. There is a loft that is 12' deep.

We live in Southwest Mississippi and the cabin gets sun from 9am to 5pm, so it's very hot in the afternoons and the a/c units (there are 2 window-type units) are not keeping it cool. Being the gambrel style, it has a lovely open, high-ceiling feel, but there's lots of hot air up there. We know we should insulate the ceiling, but money is scarce. We are considering all options. (pics attached)

1) Install fiberglass batts and leave exposed. This is cheapest since we can do the labor ourselves. However, I am worried about potential health effects of this. My mom lives with COPD so lung issues are nontrivial. Is this a health risk or not?

2) Do #1 and follow with some type of (plastic?) covering/sheeting that is not horribly expensive, that would contain the fiberglas fibers, and that we could install ourselves. What possible coverings could we use? In researching I see there are issues about insulation and which sheeting types, so we'd want to make a good choice.

3) Do #1 and then have our handyfriend come and install more of the 3/8" plywood panelling. The Gambrel ceiling seems challenging to cover. The panelling is not cheap (~$23 per 4x8 sheet) and we'd still be paying some labor, so would have to put stuff on a ccard. Would rather wait on #3 till money is easier.

Any feedback and help on this would be most appreciated, and any options we haven't considered most welcome. Willing to live with ugly in the interest of doing something this year. The cost of adding another a/c and then paying the electric bill will be covered easily this year if we do the insulation, or so we believe. Thoughts?

Thank you,
--Victoria


----------



## SeniorSitizen (Sep 10, 2012)

I can't help you Victoria but there are several members here that I suspect can.

But what I can do is commend you on the best write-up I've ever seen by a member of any forum I've ever been a member of.

And bless you for helping your Mother to be as comfortable as possible.


----------



## Victoria-nola (Aug 17, 2015)

I just thought of something else relevant: We have no building codes here.

Also, the ceiling trusses (not sure if trusses, but not joists) are on 24" centers, there are 16 voids total, each about 18-ft from side to side.


----------



## Nealtw (Jun 22, 2017)

You will need air movement from the area just above the wall to the peak to help the roof keep it's cool.
To make it safe for mom I would do insulation and finishing at the same time and call it done. 
I would use 5/8 drywall, it is fire rated, it will span 24" on center and you can tape the seams, and even if you make it ugly it is usually fixable and it is cheap.


----------



## Windows on Wash (Aug 30, 2011)

1. Not an option for the reason you mentioned. 

2 & 3 are options but I would go more towards #3 and perhaps with drywall as Neal mentioned vs. plywood. 

You don't need any more chemicals circulating in there with Mom's heath difficulties. 

3.5" of fiberglass will not make the place that much more insulated, but it will help and is the most budget friendly option. 

Look at the HD (High Density) versions of the insulation or look at Roxul as an option.


----------



## Victoria-nola (Aug 17, 2015)

Okay, folks, thank you for your thoughts on this. I appreciate your time. --Victoria


----------



## Nealtw (Jun 22, 2017)

Victoria-nola said:


> Okay, folks, thank you for your thoughts on this. I appreciate your time. --Victoria


code or not, it is all about healthy house healthy mom.:smile:


----------



## Victoria-nola (Aug 17, 2015)

Nealtw said:


> You will need air movement from the area just above the wall to the peak to help the roof keep it's cool.
> To make it safe for mom I would do insulation and finishing at the same time and call it done.
> I would use 5/8 drywall, it is fire rated, it will span 24" on center and you can tape the seams, and even if you make it ugly it is usually fixable and it is cheap.


Actually I realize, I could use some clarification on this. About the air movement statement? What do you mean there? Right now she has fans on that cross the room at head level or below, but we have been afraid to have a fan going that mixes the air from top of wall to the top of the ceiling because we thought it would make the whole room hotter to do so.


----------



## Nealtw (Jun 22, 2017)

You are talking about two different things.
Living space air, maybe you need a high window that can be opened to allow heat out.
If you are dong things that add moisture to the air like showers or cooking or just living in a small space you may want an exhaust fan.

The other I was taking about was after the walls and ceilings are closed up with insulation.
The walls and ceilings want to be sealed so any moisture inside the home can not get to the structure behind. To help keep the house healthy we want air to be able to enter above the insulation where the roof meets the wall and to escape out the top of the roof. That air flow prevents mold growing in the structure.


----------



## Victoria-nola (Aug 17, 2015)

Nealtw said:


> You are talking about two different things.
> Living space air, maybe you need a high window that can be opened to allow heat out.
> If you are dong things that add moisture to the air like showers or cooking or just living in a small space you may want an exhaust fan.
> 
> ...


Ah ok. So we are talking about some kind of vent, like soffit vents on a different kind of structure? I'm just trying to imagine what that looks like on this building, with a very thin roof shell and "cathedral" ceiling.


----------



## Nealtw (Jun 22, 2017)

Victoria-nola said:


> Ah ok. So we are talking about some kind of vent, like soffit vents on a different kind of structure? I'm just trying to imagine what that looks like on this building, with a very thin roof shell and "cathedral" ceiling.


And now I do not know how that would be done and look good too. It should have been part of the plan when the metal was put on.

But hopefully you have enough info to ask the right questions pf people who might know.


----------



## Nealtw (Jun 22, 2017)

Victoria-nola said:


> Ah ok. So we are talking about some kind of vent, like soffit vents on a different kind of structure? I'm just trying to imagine what that looks like on this building, with a very thin roof shell and "cathedral" ceiling.


----------



## Victoria-nola (Aug 17, 2015)

Thank you so much, now I understand. This was exactly why I wanted to ask this question here, was to ensure that if there were anything we needed to know about this installation that we have that info.


----------

