Insulation suggestions

[mnwebb]

Hey all,

I have a foamed in garage, 2 stories, in MN. The upper room has a peak that needs 3' of insulation (see photos) as well as some of the joists spaces (2-3'). I would like the building to be as tight as possible in order save on heat and cooling later.

What are your suggestions for such large spaces, blown in cellulose...fiberglass? Do I fill it as much as possible?

Thanks,
Wilson

 

[yeldogt]

confused: It's all foamed ? you are done.

 

[The Cobbler]

what r value is the foam?

 

[mnwebb]

R value of the current foam is between R16-19. Why not add to that?

Super insulated buildings theses days go for a roof that is R70+!

Is it a waste of $ considering what I add won't be as good as the foam?

THX!
Wilson

 

[yeldogt]

what type of foam and how thick?

Typically I do 4+ of closed and that's it ... I have done one flash and batt with 2+ inches and fiberglass in a 6x wall.

4+ inches of closed gets you in the 30 range

 

[mnwebb]

yeldogt Closed Foam is 3-3.5" in the walls and 4" inn the roof. Why do you typically just stick with the 4+?

 

[yeldogt]

In my experience 4+ of foam is all you need ...maybe in Alaska or Death Valley more may be beneficial.

I can stand in my attic on a 100 degree day and feel no heat gain from the roof .. same with my current project under both slate and standing seam. We have had single digit weeks -- again the inside walls are room temp.

Fiberglass batt insulation allows air movement --- I wish there were some better "real world" R comparisons. Because there is no comparison between even 2+" of foam and 6" of fiberglass. I have done rehabs where the addition was foam and the original house was typical construction -- the difference is dramatic.

You may have to add batt if your location mandates a particular "R" rating. It's a shame you did not go that tiny bit more .... if your location wants higher R. Even 3" is above any 6" wall fiberglass.

 

[Slowgsr]

I hate R values.

4" of closed cell out performs, tradition r45 blown in with vapor barrier etc. Air tight and air sealed is one of the most important aspects.

 

[mnwebb]

Slowgsr...What about the heat the rises to the peak of the roof, isn't that a waste of energy if its hotter up there than below, in the room?

Thanks,
W

 

[Randy in Maine]

Side question...how are you heating? My radiant floor heat is warmer than the ceiling is in my 12' tall garage.

If you are heating the air put a fan or a series of fans up there to direct the heat air down to where you are. It really doesn't take much heat to maintain Xº in a well insulated and air tight building.

 

[yeldogt]

Slowgsr...What about the heat the rises to the peak of the roof, isn't that a waste of energy if its hotter up there than below, in the room?

Thanks,
W

If you heat with radiant -- the floor will be hotter. That's the great thing about radiant

... with forced air .. yes there will be a bit of hot air up there .. if your unit is oversized . It's the reverse in the summer .. the height is your friend.

 

[yeldogt]

I hate R values.

4" of closed cell out performs, tradition r45 blown in with vapor barrier etc. Air tight and air sealed is one of the most important aspects.

Yep -- but, try and tell an inspector. they want what they want

 

[mnwebb]

Heat is combination of mini-split and in-floor heat - staple up through a wooden engineered floor.

My main question, why not take advantage of all the room for insulation that you can?

Thanks,
W

 

[TTTTTT]

In our 24x44 Gabriel style loft above the 3 bay garage, we close cell spray foamed 2-3 inches providing r13-14, and vapour barrier,then stuffed as much fiberglass insulation in as possible.maybe r60 in the upper area and r40 in other areas. The efficiency that 1000 sqft is heated and stays warm and keeps it cooler in hotter summers is amazing. We heat it with a smallish wood stove and supplement with am 18000 BTU Mini split. The setup works great. The more insulation the better.

Sent from my ASUS_Z01HD using Tapatalk

 

[yeldogt]

Heat is combination of mini-split and in-floor heat - staple up through a wooden engineered floor.

My main question, why not take advantage of all the room for insulation that you can?

Thanks,
W

Diminishing returns -- it's a question of overall temps. Delta T

 

[mike93lx]

you can throw as much money at it as you want, but at a point, it won't return any meaningful value.

How much do you spend heating and cooling? where is your heat loss?

I spend about $1200/year on natural gas for my house. i would be willing to bet that adding another $1k in insulation might save me $100/year. that's a terrible ROI and I'd be much better off putting upgrades elsewhere.

 

[yeldogt]

In our 24x44 Gabriel style loft above the 3 bay garage, we close cell spray foamed 2-3 inches providing r13-14, and vapour barrier,then stuffed as much fiberglass insulation in as possible.maybe r60 in the upper area and r40 in other areas. The efficiency that 1000 sqft is heated and stays warm and keeps it cooler in hotter summers is amazing. We heat it with a smallish wood stove and supplement with am 18000 BTU Mini split. The setup works great. The more insulation the better.

Sent from my ASUS_Z01HD using Tapatalk

That's why I go with 4 heavy .. I'm trying to get up to around 30 in the walls and go a tad deeper on the ceiling ..... if I can. Many times I'm working with old buildings and I don't have the room. I don't think the batts add very much.

I don't think it will make much difference .... but you don't place any VB in the wall. VB is still placed on the inside to protect the fiberglass. The foam does not need a VB

 

[Nivekdodge]

My new saying is "Fiberglass is for boats and Corvettes"