Wrapping my head around garage insulation

[Anarius]

Ok, so I'm starting the process of getting the [detached] garage of my home into shape, and want to start with insulation. The garage is 2x4 built, currently no interior finish except some hodge-podge shelving units someone built that I will rip out.

The garage has regular trusses and apparently soffit vents. I should just be stapling insulation between the studs (kraft in) and between the horizontal roof trusses (kraft down), right? Not following the contour of the roof.

I shouldn't need to add baffles or any other type of ventilation, if I am not blocking the soffits?

 

[LB-1911]

Give this a look -

AccuVent Roof Ventilation System

Good Luck

 

[Anarius]

Interesting. So I will still need some type of baffle system, then?

 

[Charles (in GA)]

It would help greatly to know what kind of climate you are in. Go to the black menu bar at the top of the page, and select the left most item, USER CP, then select the top most item on the page that comes up, on the left hand menu, EDIT YOUR DETAILS, then scroll down to location and plug in something, state, city, general area such as South Illinois, or North Georgia, or OZ, something, it will appear under your member name and avitar, so we will know how to best make recommendations.

Charles

 

[Anarius]

Will do, in the meantime I'm in SE Michigan

 

[theoldwizard1]

The garage has regular trusses and apparently soffit vents. I should just be stapling insulation between the studs (kraft in) and between the horizontal roof trusses (kraft down), right? Not following the contour of the roof.

You have to get your teminology straight so we know what you are trying to communicate. First this is a common roof truss.

f you do NOT have the pieces in the middle (braces or also called webbing) then it is NOT a truss. (Truss are designed so that smaller/lighter pieces of wood can be used to carry the same load. Because they are pre-assembled, they install quicker.)

Around SE MI, trusses were not commonly used until the 70s or 80s (?) becase they usually require a small crane to lift them in place (garage trusses can be installed without a crane, but it is slower.)

This is a typical gable roof structure.

Similar pieces have different names. Ceiling joist could also be called a floor joist (if you are standing on it !). Not all designs have a collar tie. If the collar ties is located 2/3 of the way down (instead of the 1/3 shown), it is usually called a rafter tie.


Most heat loss is through your ceiling. If you do not plan on using the "attic" area for storage, you are much further ahead, nailing dry wall to the under side of the ceiling joists and then adding 12" of blown in fiberglass or cellulose insulation (most big box stores will rent you the blower for free or very low cost.)

I shouldn't need to add baffles or any other type of ventilation, if I am not blocking the soffits?

True. If you do go blown in, you WILL need those baffles.

 

[p_mori7]

The garage has regular trusses and apparently soffit vents. I should just be stapling insulation between the studs (kraft in) and between the horizontal roof trusses (kraft down), right?

I shouldn't need to add baffles or any other type of ventilation, if I am not blocking the soffits?

CORRECT on both counts.

The walls should be R12 or 13, made to fit in the cavity formed by the 2x4 studs.

Your ceiling should be R20+ and will stick up above the bottom chord. If the portion of the batt that sticks up above the bottom chord will touch the underside of the roof in the eaves, you need to staple a baffle there so as not to impede airflow.

 

[mustangmike6996]

That accuvent looks pretty neat.

 

[CNGsaves]

Possible that OP has normal rafters . . . . not trusses.

Post up several PIC's as they will tell a lot . . . ie a thousand words !!


Also, what is planned heater for garage?? Btu ?? Type of fuel ??

What is expected temperature trying to maintain in garage in Michigan ??

New insulation standard for walls is R20 so it will take more effort than just R13 in 2x4 wall cavities. If outside will be re-sided, then you could put a layer of rigid foam on exterior which would get your R13 closer to R20. Also could put layer of rigid foam on inside once bat insulation put in cavities, then sheetrock over the top of rigid foam using long screws.

Ceiling should have R50 or more insulation, and blown cellulose would work up there if OP does the soffet baffles properly.

 

[LB-1911]

Interesting. So I will still need some type of baffle system, then?

If the portion of the batt that sticks up above the bottom chord will touch the underside of the roof in the eaves, you need to staple a baffle there so as not to impede airflow.

That accuvent looks pretty neat.

Readily available as well.

41 in. x 22 in. Accuvent Vinyl Attic Airway and Soffit Vent in Black
http://www.homedepot.com/p/Amerimax...gclid=CMbs87XimMQCFYNDaQodzLsAgg&gclsrc=aw.ds

In addition to the soffit vents do you have continuous ridge - gable end vents or roof vents?