# Bonus room r-values?



## BlakeJ (Aug 5, 2016)

I'm building bonus room in the attic above a garage in central Texas. Does anyone know what r values I should be shooting for on the floor, walls, and ceiling? The roof has a ridge vent, no radiant barrier on the roof decking, and it will be cooled and heated with a mini split. 

Here's my game plan so far, tell me if I'm screwing up-

Floor: do a layer of closed cell foam on the top of the sheetrock from above, then fill the rest of the space with blown in rockwool. 

Walls: radiant barrier osb with batts. There's going to be a small section of cathedral ceiling on one side, I was going to install baffles and batts for that. 

Ceiling: blown in rockwool on top of the sheetrock. 

Any advice is appreciated!


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## Bud9051 (Nov 11, 2015)

Code requirements are considered minimum but local authorities can choose their own version for guidance. A frequently quoted one is the 2009 IECC.
https://energycode.pnl.gov/EnergyCodeReqs/
That will give you a started but you need to talk to your local code office to see if they are at 2012, 2015, or now 2018. 

Creating living space over a garage will have other requirements that they can answer along with what permits/inspections are needed. Hurricane areas also have additional specifics which (knock on wood) I don't run into up here.

Bud


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## joecaption (Nov 30, 2011)

Here's another source.
https://www.energystar.gov/index.cfm?c=home_sealing.hm_improvement_insulation_table
Hope your is different but I've never once seen where they used wide enough ceiling rafters in new constrution to allow for enough room for proper baffles and insulation.
Everyone had to be built out to make room. 
Most used 2 X 4's for the knee walls where it should have been 2 X 6's.


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## user_12345a (Nov 23, 2014)

spray foam for floor, possibly for ceiling if cathedral and non-vented.

High r-value and makes good seal to stop monoxide from getting into the bonus room.

For ceiling, prevents moisture from getting into insulated assembly. Shingles don't allow for any drying so whatever gets in there gets trapped.

Something to look into is how you're going to heat and cool this addition.

Running a duct from a central hvac system won't cut it - bonus rooms have very different heat loss/gain compared to rest of the house, much more exposed surface area.

If you need heating and cooling, look into mini-split heatpumps.

I bring this up because it should be dealt with in the planning stages, not be an after-thought.


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