question for the contractors out there, R11 vs R13 insulation

[keakar]

I might just get it to add in the attic on top of the R19 as an extra layer in the attic, its only 3 1/2 more inches but the price makes it hard to pass up and im thinking that should bring the attic up to R30. just have to peel the facing off it first.

thanks for the advice guys and I wasn't aware they had R15 so i'll look into finding some of that. after all, if your going to do it, do it once and do it the right way.

[keakar]

Originally Posted by keakar

I wasn't aware they had R15 so i'll look into finding some of that. after all, if your going to do it, do it once and do it the right way.

so is there something the same thickness as r19 but with a higher r value?

I have a decked attic space so I am limited to 6" thick ceiling insulation but I do want the get the best r value there is for it. is there an r21 or something like that?

[marty f]

Originally Posted by keakar

so is there something the same thickness as r19 but with a higher r value?

I have a decked attic space so I am limited to 6" thick ceiling insulation but I do want the get the best r value there is for it. is there an r21 or something like that?

If you want the best R go with spray foam, there are do it your self kits out there. Ill be doing my own.

[fishinpox]

Originally Posted by marty f

If you want the best R go with spray foam, there are do it your self kits out there. Ill be doing my own.

Not true
Open cell spray foam @ 3.5" ( 2x4) wall is r-13 . You can achieve r15 with blown fiberglass product called "assure-r" @ 3.5" thick

But

You will get a better seal with the spray foam than you will with the blown fiberglass


Another thing with spray foam is the majority of installers and the majority of Hvac contractors don't know how to properly install / mix product or properly design a Hvac system that works with a sealed envelope

[marty f]

Originally Posted by fishinpox

Not true
Open cell spray foam @ 3.5" ( 2x4) wall is r-13 . You can achieve r15 with blown fiberglass product called "assure-r" @ 3.5" thick

But

You will get a better seal with the spray foam than you will with the blown fiberglass


Another thing with spray foam is the majority of installers and the majority of Hvac contractors don't know how to properly install / mix product or properly design a Hvac system that works with a sealed envelope

You are correct on the open cell, I should have specified closed cell. Closed Cell at 1" offers an R14 value, you have to be careful with closed cell if you are doing an attic, you have to calculate your air flow envelop and have proper ventilation. Closed cell will SEAL you roof to a point that it can be a bad thing and cause a mold situation, thus the Air flow envelop calculation, I assumed K was asking about walls.

Originally Posted by keakar

I have a decked attic space so I am limited to 6" thick ceiling insulation but I do want the get the best r value there is for it. is there an r21 or something like that?

guess I should have paid attention better

[Renegade]

Originally Posted by keakar

so is there something the same thickness as r19 but with a higher r value?

I have a decked attic space so I am limited to 6" thick ceiling insulation but I do want the get the best r value there is for it. is there an r21 or something like that?

Spray foam?

[fishinpox]

Originally Posted by keakar

so is there something the same thickness as r19 but with a higher r value?

I have a decked attic space so I am limited to 6" thick ceiling insulation but I do want the get the best r value there is for it. is there an r21 or something like that?

You should consider some powered attic vents . I don't use 2x6 ceiling joists over decked attics for that reason , ideally you want r38 in your attic