Insulation tips wanted - Building a garage with 2x6 studs

[gsebast1]

I am having a garage built with 2x6 studs in the walls. It will have brick and Hardi Board siding on the outside with Sheetrock on the inside.
I live in Texas where it gets really hot and I eventually want to HVAC the shop.

What insulation tips do you have?
Would OSB then Tyvek be a good way to sheet the building under the
Hardi Board and brick areas?
Spray foam?
Other ideas?

I don't have an unlimited budget but I really want the best bang for the buck.
Any tips appreciated.

Thanks.

 

[Firebrick43]

Please look up tyvek failures. Many pros are suggesting going back to d226 roofing felt and a rainscreen especially under hardi, wood, and brick. The rainscreen allows airflow between the OSB and siding.

Best value for the ceiling is cellulose, hands down, do r60. Doing a flash layer of foam then batt is good, flash and wet spray cellulose would be better. To save money over spray foam you could cut xps foam and use a foam gun to install between studs but it more labor intensive. Another option is to skip the OSB and use metal strapping for shear strength. Put 2" xps foam exterior of studs and your rainscreen furing strips with headlock screws

 

[ddawg16]

You don't say what part of Texas.....If Houston....it's hot and humid....or not so hot and humid. If DFW area, you only have 2 seasons....Summer and Winter.

I'd do tar paper (felt) on the outside. It's a proven and reliable material.

R19 bats in the walls. If you can go R30 in the ceiling, great. Just make sure you have the proper ventilation in the attic.

If you really want to control the temp in the garage....look at getting insulated panels for your garage door. It doesn't make sense to insulate the **** out of your garage and use an un-insulted roll up garage door.

BTW...I'm a native Texan.....Go Cowboys

 

[gtae07]

R19 bats in the walls. If you can go R30 in the ceiling, great. Just make sure you have the proper ventilation in the attic.

If you really want to control the temp in the garage....look at getting insulated panels for your garage door. It doesn't make sense to insulate the **** out of your garage and use an un-insulted roll up garage door.

I did this (R19/R30 and insulated doors). Make sure your doors are fitted well and have some kind of weatherstripping. They'll still probably be your biggest source of losses but insulation and sealing will help.

It's amazing how much the insulation helps even before the HVAC goes in.

 

[6768rogues]

Personally, I like rock wool insulation. It fits very well and is easy to install, and it has a higher R value than fiberglass.

 

[Voi]

Other ideas?

Is it too late in the process to use raised heel trusses?

 

[Firebrick43]

Is it too late in the process to use raised heel trusses?

Good point that many miss!

 

[ddawg16]

Personally, I like rock wool insulation. It fits very well and is easy to install, and it has a higher R value than fiberglass.

It's a garage....open the main door one time and any savings from using rock wool are gone.....

 

[ForceFed70]

I used the raised heel trusses to facilitate an attic room. It's a good idea, but also adds significant cost to the overall build.

Spray foam is the gold standard, but expensive. I'm not sure it's worth it for a garage that you're likely not heating/cooling 24/7 like a house but you may want to get some quotes. Otherwise, rockwool is the way to go (it's got more advantages than just a higher R value). A small price premium over fiberglass but worth it.

 

[kwschumm]

Personally, I like rock wool insulation. It fits very well and is easy to install, and it has a higher R value than fiberglass.

This. Rock wool also doesn't propagate fire like fiberglass does. Look up Roxul. Installs in batts just like the pink stuff.

 

[kwschumm]

Personally, I like rock wool insulation. It fits very well and is easy to install, and it has a higher R value than fiberglass.

This. Rock wool also doesn't burn like fiberglass does. Look up Roxul. Installs in batts just like the pink stuff.

 

[ForceFed70]

Rockwool has the following advantages over fiberglass:
- Slightly higher R value
- Critters and mold don't like it (ever moreso than fiberglass)
- Batts fit tighter resulting in less air gaps.
- Batts are firmer and less prone to sagging in the walls.
- Higher fire resistance and will improve burn ratings.
- Better sound deadening/insulation.
- Less irritating to skin/humans during install.

Rockwool has the following disadvantages over fiberglass:
- Heavier
- Doesn't compress as much when packaged meaning it takes more room in truck/trailer to transport to building site
- Cannot be purchased with a paper backing

 

[rburke65]

Well if ya got the Bucks, spray foam.

 

[DC73]

Personally, I like rock wool insulation. It fits very well and is easy to install, and it has a higher R value than fiberglass.

I agree. I used mineral wool in my shop and have been very pleased with it.

It's a garage....open the main door one time and any savings from using rock wool are gone.....

Not true at all. Using your logic, we shouldn't even be insulating our workshops.

DC

 

[MushCreek]

There are a couple things that really affect building performance. Air infiltration (leaks) has been found to be nearly as critical as insulation, so seal it up tight. Heat transfer through framing reduces the performance of the insulation by about 25%. That's why they now put a layer of rigid foam, usually on the outside, over the sheathing; under the siding.

It seems like a lot of the heat in warm climates comes through the roof, so heavy roof or attic insulation is important.

 

[matt_i]

I am also a big fan of the Roxul/stone wool. Of equal importance is air-sealing gaps in the framing/sheathing.

 

[kwschumm]

I am also a big fan of the Roxul/stone wool. Of equal importance is air-sealing gaps in the framing/sheathing.

And a great benefit of sealing every little stinking gap you can find is it helps keeps the bugs out. They will find a way but don't make it easy for 'em.

 

[gsebast1]

Some awesome tips and things to think about. I should have mentioned the garage will have an upstairs room the entire length of the garage that will be sheetrocked and and insulated.

On the outside walls it sounds like OSB, then Tyvek or tar paper?
I think I've seen the rigid foam sheathing mentioned above, will definitely look into it.