Siga and Rockwool . . . worth the $?

[newbie_garage_brutha]

This is why I spray foamed (Great Stuff) the bottom 3 inches of my wall cavity. Fiberglass in after that.

Do you suggest using spray foam or a caulk/sealant where the concrete meets the skirt board?

 

[hefnerconstructionlc]

Elastomeric polyurethane caulk would be best as it will move with expansion and contraction.

 

[newbie_garage_brutha]

Elastomeric polyurethane caulk would be best as it will move with expansion and contraction.

Thank you!

 

[Mr onetwo]

In my area Comfortboard 80 costs as much as spray foam per sq ft. I priced the SEGA product last year and it would have added about $2500 extra to a 30x40x14 building. I love RR Buildings but he doesn't pay for anything in that shop.Sort of like most of the wildly expensive stuff they use on "This Old House"

 

[Wiz02]

Thank you NUTTSGT! Cost comparison just for the walls pretax:
Rockwool R23: $4,300
Fiberglass Batt Insulation R19: $2,900

@newbie_garage_brutha Where are you buying the Rockwool? Big box store, building supply?

I too am planning to add insulation to my garage piecemeal.

 

[newbie_garage_brutha]

It's finding the product data for the soffit and ridge vents and doing the math.

I found one Certainteed 12" vented vinyl soffit and it said 5.9 SQ IN per foot. Ridge vents I find are 18 SQ IN per foot You building is 30' wide. 1/150 is .2 SF, 1/300 is .1 Soffit both sides - 11.8 SQ IN is .082 SF Ridge vent is .125. Together over .2 or a touch more than 1/150. I wish the ridge vent was half the NFA, which would be near that 60% soffit and 40% ridge and 1/200.

My instinct is you definitely don't want more ridge than soffit and would be better off with less than 1/150.

Greetings again Mr. Conner:
My builder used vented vinyl soffit the entire eave and gable! I think they need to come back and redo this based on your assessment. You are saying that my ridge vent should be 1/2 the size?
Thanks in advance as always.

 

[kngelv]

How much air will get through this without a plastic barrier. I just built a garage with OSB, Tyvek and vinyl siding. I have R-23 rockwool to install in the 2" x 6" walls. I plan on 1" x 8" by 12' long pine carsiding panels for the walls and ceiling. Will adding a plastic or siga barrier make that much of a difference?

James

 

[newbie_garage_brutha]

Hi James. I am not sure, but I am going the Siga route per direction given directly by Rockwool and the Siga folks. The Rockwool folks also suggested CertainTeed Membrain or Pro Clima Intello. Do note I am in climate zone 5A.

My interior was put on hold for at least a year, but I have roughly 1/2 of my walls filled with R23 Rockwool in just under 3 days of work - cannot stress how easy this stuff is to work with - like giant pieces of cake!

Where did you purchase your "1" x 8" by 12' long pine carsiding panels"? I may have to steal your idea!

 

[Stuart in MN]

Coincidentally, RR Buildings just received a load of rock wool insulation for their current project.

 

[kngelv]

Here is how the first wall looked. Garage is done now.

James

 

[finn]

Rockwool was recommended when I built my free standing sauna last year, so I gave it a shot.. it’s supposedly mold resistant in a humid environment, rodent resistant, and a good product to control noise.

I can’t vouch for the rodent resistance (yet), or the mold resistance, but the building is very quiet.

The Rockwool was probably 50-100% more expensive, which didn’t really amount to much for such a small building.

There’s no integral moisture barrier, which adds a step to the installation process.

There’s stuff has poor structural integrity, and it’s heavy. I had problems with it disintegrating and collapsing under its own weight when insulating the ceiling. Once it falls, it breaks apart and has to be disguarded.

I wouldn’t use it on a ceiling again because of that. I had no issues on the walls, though.

My opinion: not worth it except if noise reduction is an important objective, like a house near a highway or airport.

 

[Mr onetwo]

I am going to use TimberHP for my wall insulation and Oskorp VARISMART DUO+ for the intelligent vapor barrier in my 40x30 shop. Based on 1440 sq ft the Timber HP is around $1000 less and the Oskorp 40% less. I talked directly to the factory and they stated that the smart vapor barrier is imperative to a proper installation. Poly is a no-no. Rockwool just had a fairly substantial price increase last week and I don't know if that is reflected in my comparison. There is no shipping as it is locally made.

https://oskorp.com/varismart-duo

TimberHP Insulation for Above-Grade Applications | TimberHP

TimberHP insulation: interior & exterior, vapor-open, hydrophobic, insect- & pest-repellent, durable, Class A fire-rated, & carbon-neutral.

www.timberhp.com

 

[Overboost44]

I am going to use TimberHP for my wall insulation and Oskorp VARISMART DUO+ for the intelligent vapor barrier in my 40x30 shop. Based on 1440 sq ft the Timber HP is around $1000 less and the Oskorp 40% less. I talked directly to the factory and they stated that the smart vapor barrier is imperative to a proper installation. Poly is a no-no. Rockwool just had a fairly substantial price increase last week and I don't know if that is reflected in my comparison. There is no shipping as it is locally made.

https://oskorp.com/varismart-duo

TimberHP Insulation for Above-Grade Applications | TimberHP

TimberHP insulation: interior & exterior, vapor-open, hydrophobic, insect- & pest-repellent, durable, Class A fire-rated, & carbon-neutral.

www.timberhp.com

Thanks for this. I am getting to that point where I will need to start checking prices on all of this. Was set on getting rockwool but it was expensive enough without a price increase. Will look into the varismart but don't think I will need a vapor barrier with radiant and mini-splits on the inside and zip sheathing on the outside.

 

[pcmeiners]

Attic venting is working against the ceiling insulation in sucking interior air through it.

Yes working against fiberglass but not cellulose, fiberglass loses r value as the temperature drops. A few inches of cellulose packs down allowing very little air/moisture movement through it; cellulose only gets better the thicker it is installed. The only major negative of cellulose is if it gets thoroughly wet over a water affected material such as Sheetreock. Poorly ventilated attics work against asphalt shingles due to the heat.