Monthly Archives: March 2015

Fiberglass Batt Insulation

fiberglass-batt-insulation

What it is:

Fiberglass batt insulation is the fluffy, often pink but not always, insulation that usually comes in strips of different widths to fit between Advanced Framing, Standard Framing, or Metal Framing.  The purpose of insulation is to keep hot and cool areas separate.  It is equally important in hot climates as it is in cold climates.  It is also a sound barrier keeping your home quiet and private.  Most insulations do this by trapping air, batt insulation accomplishes this by having a thin fiber like materials trap air in pockets. Like other types of insulation it does not work as well when compressed.

Fiberglass-insulation-installation

Batt insulation is installed between studs, usually after sheathing is up, some have plastic backing that acts as an air/moisture barrier, some have a paper backing, some have a wax paper backing that also acts as a air/moisture barrier, some just sit between studs without any backing.  There is generally an additional flap of the backing material on either side of the strip that allows you to staple or tack the insulation to the studs on either side.   When installing fiberglass batt insulation you should wear gloves, safety glasses and a breathing mask as the fiberglass pieces can find their way into your skin and lungs and are uncomfortable/hazardous.

Pros:

Batt insulation is very affordable compared to other insulation types, it is very easy to DIY.  It is light weight and widely available at basically any home improvement store in various sizes and R-Values.

Cons:

You can get a fairly limited R-Value for thickness (space required) compared to other insulation types, a 3.5″ wall (standard 2×4) will get about an R-13.  It can be very irritating and hazardous to your skin, eyes and lungs if proper protection is not worn on install.  Sometimes formaldehyde (toxin) is used in the manufacturing process.  If the batt used doesn’t have a way to tack in place (and sometimes even when it does) it will settle over time and leave gaps in your wall where no insulation is present.   Water damage will completely undermine any insulation value of fiberglass batt insulation.  It is not suggested to use batt insulation in floor systems for this reason, if there were to be a flood/leak you would need to redo the entire floor insulation.

Tiny House Specific and Regional Considerations:

Often times when dealing with tiny houses space is a premium and most want more interior space, in order to get energy codes suggested R-Value in batt insulation alone you would need to increase your walls to 2×6 construction.  You are of course not required to follow energy codes for tiny homes but ‘code’ is typically the minimum level suggested for energy savings and comfort.  This all varies quite a bit by location but if you experience either high temperatures or very low temperatures you will notice a big impact from quality insulation and R-values.  Highly suggested that fiberglass batt insulation NOT be used in floor systems when they may receive moisture in the case of a flood or road damage.

For information on other types of insulation please click here.

This is a collaborative site, if you have something to add/correct leave a comment!  If you have some words of wisdom on any of the methods mentioned feel free to share in the comments!

For a list of definitions please visit the definitions page

Insulation

new-insulation-02

When it comes to insulating you’ve got a lot of options, each with their own pros and cons.  Insulation is very important in both hot and cold climates to regulate the temperature indoors and control sounds to keep your home feeling cozy and secure.  It can add structural integrity in some cases, can be extra ‘sustainable’ by using recycled and reclaimed materials, sometimes it can contain toxic materials and/or breakdown over time.  It’s important to know your options when it comes to insulation so you can consider all factors.

Insulation:

Batt (fiberglass)

Wool/Levi

Blow-In (Cellulous)

Rigid

Spray in

Thea’s Side-By-Side Insulation Comparison

Other

This is a collaborative site, if you have something to add/correct leave a comment!  If you have some words of wisdom on any of the methods mentioned feel free to share in the comments!

Framing Options

When it comes to tiny homes you’ve got a options on how to frame things!  Here is an overview of the methods:

There are pros and cons to each and what is right for you may be influenced by other choices along your path.  Stay tuned for more on each type shortly.

This is a collaborative site, if you have something to add/correct leave a comment!  If you have some words of wisdom on any of the methods mentioned feel free to share in the comments!

Definitions

Galvanized…I Beams…Loop Holes…Gussets…R-13…

Framing:

Framing

Bottom Plate – the bottom horizontal member of a wall or building to which vertical members are attached.

Top Plate (double or single) – The member or members on top of a stud wall which support the roof rafters.

Base Studs – Studs placed on a regular interval making up the main structure of the wall.

Cripple – A less than full height wall stud.

Header – Horizontal members at the top of a wall opening that transfer and distribute the weight above the opening down around the opening.

King Stud – stud to left or right of a window or door that is continuous from the bottom plate to the top plate.

Trimmer – Installed parallel to king studs to support opening headers.

Sill – A horizontal member forming a foundation.

Rafters – One of several framing members extending frome eave to peek making up the roof

Rough Opening – An opening in a wall or framework into which a door frame or window frame, is fitted.

Forces:

ad_earthquake-force-diagram

Shear:

Lateral:

Standard Framing Techniques

What is it:

Standard framing is what you typically see in wood framed structures across America.  Wood studs (Douglas Fir standard), usually 2×4 but sometimes 2×6, are spaced 16″ on center so that sheet goods like plywood sheathing, OSB sheathing and drywall (which come in 4’x8′-12′ sheets standard) can be fastened to the structure on the perimeter, these are the walls ‘base studs’.  If the spacing was any less or any more than 16″ on center this wouldn’t line up on the edges of your sheet goods and could lead to more cuts and compromising the integrity of the material (sheathing is structural and offers less structurally in small pieces).  These studs are spaced on top of a ‘bottom plate’ which is how the wall is fastened at the bottom.  There is a ‘double top plate’ which refers to the top portion of the wall consisting of two layers of studs which distribute the weight of the roof downward equally through the wall studs.  Generally standard framing is fastened with 16 penny (aka 16-d) framing nails which are 3.5″ long.

It has most commonly been recommended to use sheathing (either OSB or Plywood) that is at least 7/16″ thick in order to offer your structure enough shear strength.  There are alternatives to this such as additional strapping and T-111 siding.

Roof ‘rafters’ are generally 2×4 -2×8 lumber (Douglas Fir) placed 16″-24″ o.c. depending on dead and love loads to accommodate and length of span required as well as amount of insulation desired.  Various roof styles require different size rafters.

After you have all of your studs spaced out at the appropriate distances you can start to add your door and opening (window) locations.   Standard door and opening are framed like this:

Framing

Each opening has a ‘header’ which collects the weight that would otherwise be carried by the wall studs and distributes it downward through a trimmer and king stud.  A ‘king stud’ is a full length stud and may or may not be one of the studs you’ve got spaced 16″ on center.  A ‘trimmer stud’ directly fastens to the king stud but stops at the header which defines the rough opening height (generally 2″ taller than the height of the door being placed).   For windows you have an additional ‘sill’ which defines the bottom of the rough opening for the window.  The rough opening is generally 2″ bigger than the actual window being placed, dependent on the size of the window flanges on the window (you need enough room to level and plumb you window in case the opening is slightly out of square but not too much that you cannot fasten the window flanges on the entire perimeter).  The sill is supported by cripples which are aligned with the base studs that are placed 16″ o.c.

Generally a corner condition where two walls come together in a standard framed home looks like this:

Print

You’ll notice there is an extra stud that creates a nailing surface for the wall finish in the inside corner.  The 16″ dimension would start from the outside corner of  the structure to assure that you have a nailing surface every 4′ along the outside perimeter of the structure for your sheathing (which is structural)

Pros:

This is very commonly known, there is a lot of information out there on standard framing.  It is typically ‘over engineered’ for a tiny house and is safe so long as you follow the general rules.

Cons:

There is more lumber used than in ‘advanced framing‘ which can lead to greater amounts of thermal bridging and more weight.

Tiny House Specific and Regional Considerations:

Standard framing is itself not enough when considering the forces a tiny house is exposed to while in transit, you will need to use additional strapping to secure your roof components as well as hurricane ties to tie your rafters to the walls.  Additionally you will need to secure your walls solidly to your foundation using a minimum of 3/8″ lag bolts (recommended at 24″ o.c.).  It is also recommended to add Simpson Hold-downs at the front corners.

Wall, roof and floor thicknesses may vary based on the amount and type of insulation desired.  Typically they are 2×4 construction but in some cases more depth may be desired.

This is a collaborative site, if you have something to add/correct leave a comment!  If you have some words of wisdom on any of the methods mentioned feel free to share in the comments!

For a list of definitions please visit the definitions page