How to frame a floor

How to frame a floor

Engineered floor joists are straighter, faster, and flatter, but they aren’t installed the same way as dimensional lumber.

Synopsis: When Rhode Island builder John Spier is getting ready to frame a floor, he doesn’t place an order for dimensional lumber. He calls in an order for I-joists. These engineered floors joists are pricier than regular lumber, but because they are straighter and flatter, they can be installed more quickly. That means big savings in labor costs. I-joists are a component of an engineered floor system, and they require a specific installation process and hardware, including joist hangers. After the joists are in place, a subfloor locks together the layout.

Manufactured I-joists are used in about 45% of new wood-frame construction, and that amount is expected to rise. I can’t remember the last time I framed a new floor with dimensional lumber. To me, I-joists make more sense. They are straighter, stronger, and lighter, and they span longer distances than ordinary 2xs. They are also a more-efficient use of resources because they can be manufactured using lesser-quality trees. Of course, I-joists cost a bit more, but they also are much easier to install, meaning I get a big savings in labor.

Then again, nothing is perfect, and I-joists have a few disadvantages compared to standard dimensional lumber. They don’t cope well with careless handling, they are more sensitive to moisture, and they shouldn’t carry any load until they are fully sheathed. They also aren’t as amenable to job-site change orders, and many lumberyards don’t stock them.

I-joists are part of a carefully planned floor system

With I-joists, system is the operative word. A floor framed with I-joists is designed as a package with all its components specifically located in the overall structure. This is different from conventional framing, where joist size is selected based on maximum span and then is used for an entire floor. In an I-joist floor, components have the same depth, but flange widths, joist spacing, and attachment details can vary throughout the system to make the most-efficient use of materials.

The first step in building an I-joist floor is having it designed. I provide lumber suppliers with complete sets of building plans, which they pass along to one or more engineered-lumber vendors. In a week or two, each vendor sends me floor-framing plans and quotes for the I-joists, beams, blocking, hardware, and other material.

How to frame a floor

It’s important to review the engineer’s floor-framing plans carefully, especially to make sure that they work with the builder’s plans. Sometimes the engineers miss a key element and design a framing plan that doesn’t accommodate the plumbing or the ductwork, or they might specify some details that experience has taught me to avoid. On the other hand, an engineer sometimes simplifies and improves the structure by coming up with a framing plan that I hadn’t envisioned.

I also review the attached materials list carefully. If the engineer has specified a lot of mixed, short-length pieces, I often combine them into longer lengths that can be cut to length on site. The longer lengths are easier to handle, reduce waste, and give me a margin for error if I make a cutting mistake later or find a damaged piece in the pile. Blocking panels, which are short lengths of joist used to transfer loads over bearing walls, are often listed as a pile of separate 2-ft.-long I-joists, but I can save myself some money by getting these short pieces out of cutoffs instead.

I also always buy one extra of the longest joist just in case; if I don’t use it, I can return it. I check the beams, too, because I often can combine them into continuous lengths that are stronger and can be installed faster. Finally, I check the hardware list. If the engineer has specified hardware items that I’m unfamiliar with, I look them up in the catalog to see how they are installed.

How to frame a floor

From Fine Homebuilding #197

For more photos and information on how to frame a floor using I-joists, click the View PDF button below.

Sign up for eletters today and get the latest how-to from Fine Homebuilding, plus special offers.

How to frame a floor

This step by step diy project is about how to build a 8×10 shed floor. Building a shed floor is the first step if you want to make a shed by yourself, but it has an essential role for the durability of your project. Therefore, we recommend you to work with attention and to adjust the size of floor to your needs. Use quality lumber when building the joists, as they need to support significant weight.

Building a small shed is a must-have project for any family, as there many things that should be stored and protected from bad weather. The first step of the woodworking project is to build the floor structure. As you will see in project, you need to make a proper planning and to invest in the best quality materials you could use. Make sure you study the building codes, as to get accustomed with the local building codes.

Place 4×4 skids under the floor frame, as to distribute the weight of the construction in a professional manner. In addition, choose a proper location and level the surface until it is perfectly horizontal. Place a few concrete slabs under the skids, as to protect the wooden components from moisture and water damage. Check if the corners are right-angled after adding each component. See all my Premium Plans in the Shop.

Made from this plan

Building a shed floor

How to frame a floor

Building a shed floor


  • A – 3 pieces of 4×4 lumber – 120″ long SKIDS
  • B – 9 pieces of 2×6 lumber – 93″ long, 2 pieces – 120″ long JOISTS
  • C – 1 piece of 3/4″ plywood – 48″x96″, 1 piece – 24″x48″, 1 piece – 48″x48″, 1 piece – 48×72″ FLOORING
  • 3 pieces of 4×4 lumber – 10 ft
  • 9 pieces of 2×6 lumber – 8 ft
  • 2 pieces of 2×6 lumber – 10 ft
  • 3 pieces of 3/4″ plywood – 4’x8′
  • 2 1/2″ screws
  • 1 1/4″ screws
  • glue, stain
  • wood filler


  • Use a good miter saw to make the angle cuts
  • Drill pilot holes before inserting the screws
  • One Week


  • Part 1: How to build a shed floor
  • Part 2: How to build a small shed
  • Part 3: How to build a roof for a shed
  • Part 4: How to build a door for a shed

How to build a shed floor

How to frame a floor

Building the floor frame

The first step of the project is to build the joists for the floor frame. As you can notice in the image, we recommend you to use 2×6 lumber, as the floor should support a lot of weight. Take accurate measurements and get the job done with a good circular saw.

How to frame a floor

Spacing the joists

It is essential to place the components on a level surface, if you want to get a professional result. Drill pilot holes trough the rim components and insert 3 1/2″ screws into the joists, after making sure the corners are perfectly square. Follow the information shown in the diagram, as you need to leave a certain distance between the joists (16″ on center).

How to frame a floor

Attaching the frame to the skids

After building the frame for the shed floor, we recommend you to place them on top of several 4×4 skids. As you can see in the image, you need to align the skids before placing the frame on top of them, as to distribute the weight efficiently.

How to frame a floor

Attaching the plywood flooring

One of the last steps of the project is to attach the plywood sheets to the flooring. As you can easily see in the image, we recommend you to use 3/4″ tongue and groove plywood and to follow the pattern shown in the image.

How to frame a floor

How to build a shed floor

Last but not least, we recommend you to take care of the finishing touches. In order to get a professional result, fill the holes and the gaps with wood filler and let it dry out for a few hours. Check if there are protruding screws and fix this issue, if necessary.

Thank you for reading our project about how to build a shed floor and we recommend you to check out the rest of the projects. Don’t forget to share our projects with your friends, by using the social media widgets.

How to frame a floor

How to build a shed foor

Having a sturdy shed floor is crucial to maximizing the life of your shed.  If the construction is not done properly, a multitude of problems will and can occur over the life of your shed.  Here are just a few:

  • Initial construction will be harder for the rest of your shed if you don’t build the floor right.
  • Door can become warped.
  • Windows can leak.
  • Roofs can leak.
  • Dangerous conditions can continue to crop up.

How to frame a floor

Wooden Shed Floors Should Be Anchored Down

How to frame a floor

Proper Shed Floor Construction is Crucial!

There is more than one way to build a shed floor and this is how I build my wooden shed floors.

The following instructions refer to different terms like band boards, rim joists, floor joists, and skids. If you are unsure of what those terms are please have a look a my shed floors page.

1. Check your local building codes if you haven’t already to determine what type of anchoring you need to do for your shed.

When building your shed floor its a great idea to check your local building codes.

Chances are if you have applied for a permit you’ll know the answer to this question already. Usually, there are two types of anchoring if you are not building on top of a concrete slab. One way is to anchor your shed to the ground using cable tie-downs, or anchoring it with your floor being fastened securely to posts which are sunk into the ground at a pre-determined depth in concrete.

Make sure whatever is required by your county that you follow their guidelines.

2. Gather the proper lumber to cut your floor joists, rim joists, and 2 two band boards and 4×4 skids. Cut all floor joists to proper length along with your 2 rim joists and two band boards and skids. Also, cut your 4″x 4″ skids to length.

3. After cutting all lumber, mark off your two band boards for joist layout at 12″ on center. Assemble the frame using 16d galvanized common nails, making sure to check each joist for crowning and install it with the crowned edge up. 

Building your shed floor on skids.

How to frame a floor

Taking Diagonal Measurements

4. Lay out your 4″ x 4″ skids properly spaced and lined up on your foundation, making sure they are level. Set the floor frame on top of the skids and measure the diagonals from one set of opposing corners then the other set of opposing corners to make sure it’s square.

At this point, toe nail all joists to your skids using 16d common nails. The joists which fall at the 4′, 8′, and 12′ ( joists that are on the 4′ increments) lengths along your skids should be measured before nailing to make sure they are nailed exactly on center at those distances. This way, when laying your decking (or flooring) down, your edges will fall right in the middle of your joists for easy nailing. 

5. Whichever method you need to use for anchoring your shed,  it should be done at this step before laying down and nailing your floor sheeting. 

Stagger your floor sheeting when building your shed floor.

How to frame a floor

Stagger Your Floor Sheeting

How to frame a floor

Shed Floor Sheeting with Treated Plywood

6. Now lay out your floor sheeting starting with one of the front corners first. The reason for this is that you want the front part of your floor looking nice.  It’s the first thing visitors will see when stepping into your beautiful new shed. Use 8d galvanized box nails driven every 6″ along the edges and every 12″ in the field. 

7. It’s best to nail the shorter 4′ side first.  This way you will be able to pull the longer side over to align up with the outside edge of the floor framing.  This will ensure that your floor sheeting will be squared up properly.  Of course, if your floor framing is not perfectly square then your floor sheeting is not going to line up properly.

Here’s an example of laying floor sheeting on an 8×10 shed floor.

How to frame a floor

Steps For Laying Shed Floor Sheeting

Adding a ramp to your shed floor.

alt=”Adding a shed ramp to your shed floor” width=”500″ height=”281″ />Building a ramp to your shed floor

It’s easy to add a ramp to your shed floor. Many sheds will serve the purpose of having a place to store riding mowers, 4 wheelers, outdoor equipment, etc.  You’ll want to build a ramp to make it easier to move these items in and out of your shed.

How to build a shed ramp.


Do You Have a Question about Building Shed Floors?

Enter your question below

What Other Visitors Have asked.

Click below to see questions about building shed floors from other visitors to this page.

Floor Joist Spacing
I have 16′ x 16′ footer in my back yard with 6″ block walls on it. The northern wall is 16′ outside measure long. The eastern/western walls are only 7′ …

Depth of anchors
Here in Florida freezing is not an issue. How deep should I place 4×4 posts and 12” concrete cylinders to ensure solid foundation and anchorage in our …

What are the two common footing problems with Piers?

Sagging, sloping, and buckling floors are common issues with pier and beam foundations. The type of repair for pier and beam foundations depends on what exactly the problem is. Repairing a pier and beam foundation may require replacing rotten wood or installing new beams and joists or even re-shimming the foundation.

Where is the rim joist located?

Rim joists are located at the top of your basement walls. They usually look like wooden squares going around the perimeter of your basement. The main purpose of a rim joist is to support the weight of the floor resting on the joists.

What do floor joists sit on?

At the foundation level, floor joists rest directly on a sill that is treated with preservative so that contact with the foundation will not promote termites or rot. Their exact construction and connection with the wall studs depend on the method of framing that is utilized.

What size lumber is used for floor joists?

There are several different sizes and types of floor joists. The most common sizes are 2×8, 2×10, and 2×12.

How do you nail floor joists to sill plate?

Start an 8-penny nail as a toenail, 1 inch from the end of the joist and 1 inch from the bottom of the joist. Drive the toenail into the sill plate at a 45-degree angle, but do not drive it fully at this time or you will move the joist off of the layout mark.

Do you install subfloor before framing?

If you use a product like DriCore for the subfloor, they even explicitly recommend you frame on top of their subfloor product. They do, however, recommend you screw the framing through the subfloor into the concrete with something like 3″ Tapcons spaced every 4 ft through the bottom sill of the framing.

Do I need a subfloor over concrete?

If you don’t plan to use the space, there is no need for a subfloor or floor covering. Concrete or tile-over-concrete are acceptable floors for uninhabited basements. But to install any kind of floor covering—engineered wood, laminate, carpeting—basement subflooring is highly required.

How do you install floor joists on a concrete slab?

Install it flat on the slab surface, with the outside edge aligned against the side wall or the edge of the floor line. Secure each length to the slab with concrete nails spaced approximately 32 inches apart and 8 to 12 inches from each end. These will be the end “sill plates” that support the ends of the floor joists.

What raised foundation?

A raised foundation is the physical structure of the footings and walls or piers that support the home to create the crawl space.

Is it cheaper to build on a slab or piers?

Concrete slabs can be constructed very easily and are cheaper than pier and beam foundations. However, you should know that repairing and maintaining a concrete slab can be more expensive in the long run than taking care of a pier and beam foundation.

How far apart should foundation piers be?

While 8 to 10 feet apart is a sufficient distance for foundation piers to support most structures that would sit atop a post and pier foundation, if the building is particularly tall or made of heavier materials such as brick or metal, it’s not uncommon to place the foundation piers even closer together.

Is post and pier a permanent foundation?

Post and pier homes, manufactured homes, modular homes, and mobile homes are just a few homes supported by piers. Furthermore, piers can be made from stacking concrete blocks. So, often you will find piers considered a permanent foundation.

What is the purpose of rim joist?

In the framing of a deck or floor system, a rim joist is attached perpendicular to the joists, and provides lateral support for the ends of the joists while capping off the end of the floor or deck system.

Why is a rim joist necessary?

The main job of a rim joist, also called a band joist, is to provide lateral support for the joists, to prevent the joists from leaning under the weight of the load-bearing walls resting on them.

Is rim joist necessary?

Yes, if your framing a house or a deck you’ll need a rim joist. They create the edge of your floor framing and close off the open edges. For example, if your framing a 10×10 deck off the back of your house, you’ll probably be using 2×8 or 2×10 joists spaced 16 inches on center.

Does Sistering floor joists work?

Sistering joists means beefing them up with additional material. Doing so strengthens weak joists and can help straighten sagging joists. Framing lumber is the typical choice for sistering material, but engineered lumber products actually add more stiffness than dimensional lumber.

What is nailed to the top of the floor frame?

The subfloor, also known as rough flooring, is nailed to the top of the floor frame. It strengthens the entire floor unit and serves as a base for the finish floor. The walls of the building are laid out, framed, and raised into place on top of the subfloor. Panel products, such as plywood, are used for subflooring.

How long can floor joists be without support?

With 16” spacing, a floor joist can span up to 14′ as long as it is not cantilevered and terminates with support on either end. If the joists are 24” apart, then one 2×10 joist can span up to 11′ 5”. These lengths are for SYP lumber.

Are 2×6 OK for floor joists?

2 Answers. 2×6 joists at the span that you are talking about (16′ and 18′) are not strong enough to support a floor as a living space. With a span like that the timber size that you sister in would have to be at least 2×10’s.

Can 2×4 be used for floor joist?

It should be OK, but I’d go closer than 16″ OC. 2x4s are cheap. another option might be to put plywood below the joist as well as above. This would make the plywood the stressed member and the 2x4s would be acting more like the webbing of an I beam.

Do floor joists need cross bracing?

For a new home, you’ll want to install cross braces during the construction of the floor frame, to avoid the aforementioned floor problem in futures. Basically, cross-bracing your floor joists makes your wood frame floor system stiffer, consequently preventing twisting, deflection, squeaking, sagging, and bouncing.

Can you build your own floor trusses?

Do not build a floor truss without understanding how to build it to fit your specific needs. Floor trusses are custom built to meet specific construction needs. One of the most common support systems for floors in houses and commercial buildings is the open-web truss system.

What is the typical size of floor joists?

Typical Floor Joist Size In Residential Construction Floor joists range from 2×8 to 2×12. It is less common to see joists that are 2×6, even though they are included in joist span tables. Older homes are more likely to use 2×6 for joist framing.

Type your search KEYWORDS In the Box Above. For Example: Foundation Drain, Framing, Cracking, etc.

    Browse Categories:

TJI Framing

TJI Floor Joist Framing

How to frame a floor

Engineered lumber continues to become more and more popular in today’s construction industry. TJI’s (engineered wood I joists) are my preferred framing members for floor systems. TJI’s offer many benefits compared to traditional dimensional lumber joists including: almost no twisting or warping, very little dimensional shrinkage, stiffness and strength.

Framing a floor with TJI’s is really no different than framing with dimensional lumber. The one big difference is the hardness of the material which makes nailing into it a bit more difficult. Engineered joists are also a little less stable (can’t walk on them) until the sub-floor is installed.

TJI’s are available in many different sizes ranging from 9-1/2″ to 16″ deep and flanges 1-3/4″ to 3-1/2″ wide. The wide range of sizes allow for framing many structures from residential houses to commercial buildings. Check out one of our other articles on How To Size TJI Floor Joists.

Engineered Lumber Beams

How to frame a floor

In addition to the TJI joists, we also use TimberStrand LSL Rim Boards and Parallam PSL Beams. The rim boards come in the same depths as the TJI joists. Parallam PSL Beams are the workhorse of beams for most buildings that we construct. Occasionally we’ll use the Microlams (LVL Beam) but PSL beams have great capacity and available sizes. Most lumber yards can help you size the beams to meet local and State building codes, otherwise you should consult with an engineer. You can read more about Engineered Lumber and why I think it’s a good investment.

Dropped Vs Flush Joist Framing

This particular floor system has two framing approaches. For the framing shown in the photo, the beams are framed “flush” meaning they are in the same plane as the joists. This type of “flush” framing allows for more head room below. At the other end of this house there is a beam that is framed “dropped” which means the beam is framed below the joists such that the joists rest on top of the beam.

How to frame a floor

In order to frame in a “flush” beam you’ll need appropriate hangers. As you can see in the photo hangers have been installed along the face of the carrying beam in order to carry the TJI joists. Anyone that’s ever nailed into a PSL beam will tell you it’s like trying to nail into rock.

That’s why I recommend you buy a Bostitch MCN-150 StrapShot Metal Connector Nailer. This pneumatic nail gun is specifically designed to allow you to shoot 1-1/2″ hanger nails directly into the pre-drilled hanger nail holes. This gun is an absolute necessity if you have any significant amount of hangers that need to be attached to PSL or Microlam beams. Metal Hanger Nail guns are specially designed to allow you to see the nail tip in the hole prior to shooting it in. This allows you to get each nail into the correct hole.

Installing Sub-Floor Over I-Joists

Once all the framing is in place we install 3/4″ Advantec sheathing on the deck. I highly recommend that you use a significant amount of PL Polyurethane Construction Adhesive between the Advantec and the TJI’s. Then make sure to either nail it down with ring shank nails or even better with screws. If you skimp on this step you’ll forever be haunted with floor squeaks. So don’t say I didn’t warn you, trust me, I’ve seen this happen far too many times.

How to frame a floor

How to frame a floor Want to know more about floor structure? Check out this new BOOK!

Floor is a structure supported by the building foundation directly. In small houses where no deep concrete foundation along the entire perimeter is considered, the floor will have to resist fluctuating temperatures as it is in direct contact with the exterior environment. Therefore, include sufficient thermal insulation in your calculations, primarily in cool weather conditions.

The floor structure distributes the load from the walls, upper storeys and roof straight to the building foundations. In the positions of planned load-bearing walls and partitions, the floor structure should be designed to avoid too much of a deflection. It can be achieved by appropriate location of load-bearing components in the floor structure with the right size of spans between them reflecting on the future users’ demands and estimated load it will create. This information should be included in all good project documents.

There are more different parts, which have direct influence on stability and load-bearing capacity of the floor structure. For example: sizes and types of the beams and joists used, way of their connections, how they are combined or what kind of blocking is chosen, which acts as a bracing. Base board of the top floor layers has also an important role in bracing the entire structure.

How to frame a floor

Small cabin Cheryl, construction of floor layers

Individual floor layers and functions thereof

From the point of view of humidity and heat transfer, this is identical to the structure of walls and roofs; therefore, the cluster of layers is encountered here as well. Asphalt sheet often used for protecting wood from other materials separates foundations of the building from floor joists. They act as load-bearing elements together with another set of wood floor joists, which are placed on top of them in perpendicular direction. In-between these is an insulation. It is protected by vapour-permeable air barrier material letting the moisture out of structure while preventing the exterior moisture in, and wire lath underneath, protecting the insulation from outdoors environment.

This can be replaced with different material such as OSB or plywood, but holes must be drilled in the boards in order to facilitate vapor elimination. Their surfaces can also be coated with bitumen, together with parts of foundations, because it further improves the floor structure protection. From the other side of insulation, on top of it, is a vapor barrier separating the insulation and indoor environment. Base board is placed on top of this helping to distribute the loads and supporting the final interior floor finish. Material for this top floor layers needs to be carefully chosen to be easy to repair and renovate, as frequent floor usage may make it worn after a while, and also have good acoustic and thermal insulation properties. Therefore solid wood is better option than sandwich-structured composites

How to frame a floor

DIY construction guide

For more information about simple timber frames, floor structure, how to build a floor and other parts of DIY construction, check out the How to build a tiny house book with step by step guides, illustrations and descriptions.

Wood Framing Floor makes wood framing of floors fast and easy with real-time full project updates in Autodesk® Revit®. Plus, it generates views with automatic dimensions for floor panels or segments as well as accurate bills of materials and shop drawings. So quality production and accurate assembly on site are ensured.

Connectors, cuts, supports, and other details can be distributed based on predefined rules or connection types. They can then be modified or updated to suit the project design stage and the level of detail required. Floor frames and the layout of frame elements and details can be modified and updated whenever the project is changed. Dynamic update functionality can make changes to all floor frames of the same type at once.

Floor frame elements in the project can be easily marked based on their properties and locations in the floor structure layer. And information for fabrication can be automatically generated with all desired views, schedules, and drawings for each floor segment or panel.

The trial version and full version are both included in the Wood Framing Floor App. After downloading the app, you will have the option to take a free 14-day trial or to purchase. Activation codes are sent via email.

By downloading the Wood Framing Floor App, you will also receive our TOOLS4BIM Dock. The Dock gives you the option to install additional Revit add-ons developed by AGACAD. These other Revit extensions cover a range of industries, including Metal & Wood Framing, Ventilated Facades, Curtain Walls & Panels, Precast Concrete, MEP, and more.

Activation codes are sent automatically by email for trials and purchases of Tools 4 Revit add-ons. Codes are sent manually by email for purchases of BIM Solutions.

Note: This app uses a custom installer (and not the standard App Store installer).

How to frame a floor

Proper joist sizes can easily be figured out from the IRC (International Residential Building Code) using a table in the same way you calculate header sizes. For me, that meant looking at the part of the table that dealt with 24 inch joist spacing since that is what I’m using. Then figure out what the greatest distance the joists will span is, which for me is just slightly over 14 feet. Last, select a lumber option that supports a minimum span greater than this distance. I decided to go with #2 2×12 Douglas Fir, which supports a span of up to 16’6″. Going with an option suitable for a span larger than what I need will hopefully give me a less bouncy, less squeaky floor.

How to frame a floor

Lifting 16 foot 2×12’s 10 feet up in the air solo is a great workout. After cutting each joist to length. I lifted one side up in the air and rested it on the top of an exterior wall. Next I moved a ladder near the interior bearing wall and lifted the other end of the joist up so I could rest it on the top of the ladder. After climbing up a few rungs on the ladder, I had enough height where I could lift the joist from the top of the ladder to rest on the interior wall. Just as with the wall framing, it was important to ensure that the crown of the lumber faced the sky.

How to frame a floor

The first joists I installed are called the rim joists. These run on the top of the exterior walls perpendicular to the rest of the joists. Above you can see the rim joist on the left side of the corner and the outermost floor joist on the right side. Using rim joists ensures that there is a perimeter of joists all the way around the house even though the majority of the joists run in the same direction. The rim joists are “toe-nailed” to the top plate, meaning that they are nailed diagonally. Once the rim joists are up, the other joists are placed perpendicular between them and nailed to the rim joists, as well as toe-nailed to the exterior walls.

The opening for the stairway required a little bit of detail. The code requires joists to be doubled all around the opening. In addition, any time you are unable to rest a joist on a bearing wall, you must use steel joist hangers to carry the weight around to where it can reach a bearing wall. The manufacturer of the hangers (in this case Simpson Strong-Tie) tells you what kind of nails you must use and what amount of weight the hanger is capable of carrying.

How to frame a floor

Except for a very brief stint on the scaffolding system, we’ve been working in a giant hole in the ground all summer.

How to frame a floor

How to frame a floor

How to frame a floor

You can click this diagram for a larger view.  Only one half of the floor joists are shown in the diagram.  Both sides are to be completed the same.

We did quite a bit of planning and figuring for this floor.  Although, it’s really a simple floor, with floor joists being hung on the hangers on the ledger boards, and resting on top of the center load bearing wall.  I guess it’s the tons of planning that makes things really simple!
I’ll cover in a second post the stair openings – for those of you interested in the easy way I could come up with for framing a split level entry.
The joist need to span 20 feet 9 inches long and with everything else on 16″ centers, we knew the floor joists should be 16″ on center.

How to frame a floor

Using span tables, these from the TGI joist manufacturer’s website, we knew we would need at minimum 14″ TGIs.  TGIs are basically engineered floor joists that tend to be straighter and stronger than tradditional 2x boards.  You’ll see lots of pictures of them in this post and beyond, I promise.

One of the downfalls of living in Alaska is you can’t always get what you need, unless you special order it.  With winter fast approaching, we do not have seven weeks to wait for 14″ TGIs.
So we went ahead with what was stocked locally, the 16″ TGIs.  Thus the matching 16″ LVLs and Rim Boards in this post.

How to frame a floor

Good thing they deliver! The Joists arrived in 60′ lengths.

Note to other builders – we really wish we had spanned less than 20 feet, because under 20 feet we could have used 12″ TGIs for major savings. And because the cutoff for not having to buy all 60 feet of the joist is 40 feet, we are left with a pile of 18′ scraps and quite a bit of money wasted . so consider building under 40 feet overall as well. Lessons learned . oh well, Mom get’s a wider hallway out of the deal!

PS – The 18′ scraps won’t go to waste, we just have no use for them on this jobsite.

How to frame a floor

First we take a measurement of the length needed for the joist, and then mark a joist to this measurement.

How to frame a floor

Then “stickers” are put under the joist on either side of the cut to elevate the joist at the cut. Then the joists are cut to size.

How to frame a floor
Later we would get smart (Thanks Uncle Bill!) and add a piece of plywood over the OSB part of the joist so cutting with a saw isn’t such a bumpy ride. Think of it like trying to ride your bike down one sidewalk curb, across the road, and up another sidewalk curb . much smoother if everything is the same height!

How to frame a floor

I really miss this guy, cause now it’s my head holding up the other end. That, and he’s remarkably optimistic and just in general makes work more fun and funny.

Anyway, the center end of the joists are lifted up on to the center load bearing wall.

How to frame a floor

And then the other end is lifted up and snapped in to the preinstalled joist hangers.

I tell you, this system is slick. Everything just works together so smoothly!

How to frame a floor

Of course anytime work is going smoothly, you are either headed for a not so nice surprise, or you’ve done your homework. 

In our case, we’ve put in quite a bit of time planning, and you can see, we even placed the anchor bolts so they would not hit on a joist. We did this by simply marking all joists on the foam blocks before putting the anchor bolts in.

How to frame a floor

Once all the joists are in, it’s almost like we are upstairs . almost.

Boards are layed over the joists, and marked 16″ on center. Then the boards are screwed to the tops of the joists to the marks to keep the joists in the right position until plywood is installed on top.

How to frame a floor

Then scraps are used to create blocking over the center load bearing wall. You see, with a wall on top and bottom, the joists could get “squished” and the blocking will help out tremendously here. If you are installing TGIs, consult your manual or the manufacturer’s website on blocking and web stiffener requirements.

How to frame a floor

So all we need now is plywood on top of these joists and we’ll be upstairs!