Lowering Ceiling for Better Insulation

[2canSAM]

Hi all,

I have a 1995 Fleetwood, 54x27 DW that has the peaked ceilings. While replacing a light fixture this summer I noticed there is only about 6 inches between the ceiling and the roof of my home. I also noticed how extremely hot it was in that area between the roof and ceiling. After looking at some newer mobile home I got to thinking about lowering the ceiling line. Right now at the exterior walls the ceiling starts at about 7 1/2 feet high and graduates to about 13 feet high where the home comes together. I was thinking of dropping the center peak to about 10 feet. So it would go from 7 1/2 feet on the outside walls to 10 feet in the middle. This would allow me to add extra insulation between the "old" ceiling and the "new" ceiling. Any thoughts on this?

[SpongeBob]

Greetings and Welcome to this great forum.
As I understand your question, you are concerned about the heat between the 6" space above your ceiling and below your roof. If no roof damage is resulting because of this, (I'm sure your roof is vented) I personally believe that most of us would give our eye teeth for those high ceilings. If your concern is to conserve indoor heat for the winter, then you might want to consider a ceiling fan instead of doing all that work! Again, welcome to the forums and keep watching as other will surely chip in with advice for you! Also, adding a profile helps all the great folks here answer your questions more presicely.

-Bob

[2canSAM]

Bob thanks for the welcome, and the fast and thorough response. I am mainly concerned about heat/cool air loss, We have fans in all rooms of the home right now. I really got concerned with energy efficiency this summer as our AC unit would never turn off and still would only cool to 78-80 degrees, in Central Alabama. I assumed a big reason for this was there only being 6" of insulation between the heat absorbing roof and my ceiling. I am updating my profile now, Thanks again.

[Dean2]

It sounds like You want to modify the rafters into trusses. Trusses *without* a flat cieling underneath.If You install truss plates at every joint I believe they add to strength quite a bit.

After the new attic area is created vent it well both high n low for air draw/expell by whatever means will work with Your place/budget.

There will be some tricky(sharp) angles when cutting the new truss materials but if You know the existing angles(pitch)then a formula or even a pattern can be used.

My standard question;;Is Your foundation designed for added weight? Have You had any recent settling probs?

Firecode sheetrock is required for cielings but I do'nt know if it would be needed if the old layer is somehow left mostly intact and the holes resealed,sort of a "sub-layer" fire protection..I think it would be easier to just use another layer and finish (tape,mud,texture) it normally,,maybe tear off all the old layer for weight reduction since You will be adding material.

I sure hope I'm making sense,there are so many things to consider it's impossible to list or forsee it all.

as a side note; I never thought the change to vaulted cielings as the norm was a good idea. Even with the better modern materials/methods considered an old-style flat cieling makes for less cubic feet to heat/cool. Essentially it is conservation over looks,,pretty important again these days and IMO always should have been. There are a ton of arguments to this but it comes down to simple numbers in the end. Less area should take less energy. Seems that folks(Home Buyers/Designers)just forgot the fuel shortages of the past during a time of plenty and helped to create another time of shortage concern sooner than it coulda been. Long side note huh? Sorry.

Dean

[JD]

Hi and welcome to the forum.

Adding insulation to the roof/ceiling would be very beneficial, but there are some considerations. For one, when dealing with warm air vs cold air, air will take the path of least resistance and flow like water. When adding insulation to a roof or ceiling it is important that it is consistent in R value across the entire surface. Right now with a consistent R19 insulation in your roof, you are losing or gaining heat evenly across the entire ceiling, which allows for better dissipation of water vapors. By adding a lot of insulation to the peak area and little to no insulation at the eave, the air escaping the room will flow to that eave area to escape. By taking away the even dissipation of the vapors and condensing them to the eaves, you could be creating a moisture build up problem.

Another consideration is by adding a second ceiling, while leaving the original ceiling intact, you could be creating a double vapor barrier/diffuser that can trap water vapor allowing it time to change from the gaseous state to actual moisture.

A proven method of adding insulation to your roof/ceiling is installing a fully engineered insulated roof-over product. You can see an example of an insulated roof product at www.centralvalleyrepair.com . Just click on the "New Roof" link. This roof product is currently only available in parts of California but you may be able to find a similar product in your area.

A half baked "off the top of the head" idea would be to add a 5.5" truss system under the entire ceiling to add additional insulation. Again, considerations of double vapor barriers and total roof weight would have to be figured out. You would be betting your carefully thought out plan would be as good or better than professional engineered and approved ceiling design you already have.

One HBOTTOTH idea would be to remove the existing ceiling and vapor barrier (visqueen) that is immediately behind the ceiling (not all ceilings are designed this way), and sister a 10" strip of CDX plywood to the existing rafter/truss. At the bottom of the plywood, you can attach a furring strip even with the bottom of the plywood which will act as a nailer for a 1x4 for flat surface to attach the new ceiling to. Maybe furring strip nailers on both sides of the plywood. Then you can add your vapor barrier and new ceiling. It is just my thinking that using minimal wood would keep the weight factor down. The plywood would have less flex than almost any other material you could use and CDX is cheap. Again, this is just thinking and not a proven plan. I can't say for sure whether you would have a water vapor problem regardless what you do. That would depend a lot on your local climate and your use of the home.

JMO
JD

[2canSAM]

Great points you all have made. The added weight would be a huge concern. Sounds like I would be better off using that money to plant some shade trees by the house, right now my house is directly exposed to the sun on the east side from morning till about 3pm. Also going to upgrade to some better windows. Thanks all.

[JD]

Both excellent choices!