Floor framing home construction plan

Now we’re cruising in our home construction plan that we’ve designed.

The framing and rough work are a lot of fun and you will see the house starting to take shape. It’s at this point where you will see great results with a small amount of effort. This is also the point where you will start gaining valuable knowledge and experience about carpentry.
Now that the foundation is complete, it’s time to put on the sill plate. Remember the sill plate is what attaches the house to the foundation. It is a board that covers the top of the foundation so you have something to nail the floor joists to. This is typically a 2×6 for cement foundations and a 2×8 for block foundations.

The trick is to get a good fit over the anchor bolts. You can make the anchor bolt holes larger than they need to be to get a good fit. Once the holes are drilled and the sill plate is resting on the foundation with the anchor bolts sticking through it, you will fasten them down with heavy washers and nuts.

Tighten them down really well while at the same time making sure that the plate is in square with the foundation wall. Also, the plate needs to be level.

sill plate

Tighten down the anchor bolts evenly all the way around the foundation to prevent binding which will make an uneven surface.

Once the sill plate is on you can start to put on the rim joist. By the way, if you live in an area where there are termites, you’ll probably want to use arsenic-treated lumber for the sill plate. Most pressure-treated lumber is injected with arsenic. Sounds kinda cool, huh? ARSENIC! It’s really no big deal though unless you’re a termite.

Now, you will make the Rim joist using 2×10’s. They will rest on the sill plate.

rim joist

The rim joist is the outside perimeter that the floor joists are attached to. The floor joists are easy to fasten down because you can nail them through the outside of the rim joist. You can use either 2×10’s or I-joists for the floor joists in your construction plan for your house.

rim joists

Because most foundations are wider than boards are long, you will probably have to run a girder or girders up the middle to help support the joists.

It helps to offset the joists over the girder. You also need to add bridging between the joists for stability as well as fire blocking.

floor joists


The girders can be made by nailing 2×10’s together, just be sure to straddle the joints.

The post holding the girder can be a 4×4 on a cement pier or even a deck block. The post or block needs to be on a concrete footing though, so you will need to plan ahead when doing the foundation work in your construction plan.


floor joist

Sometimes the 2X10’s look a little ratty after they’ve been used for forms, but they work just fine.

While you have the floor open, now is a real good time to run some plumbing. Your home construction plan waste lines are 2 and 3-inch ABS pipes that are really difficult to put in once the floor is covered. You can put pipes through joists, but be careful not to weaken the joist. A reinforcement block should be put in.

As a final touch, you might want to brace the joists for more stability. It also helps reduce the chance of squeaky floors.

Now is also a good time to run water lines and even electrical wires under the floor along the joists. Remember, it’s much easier to do it at this point than to be crawling around dragging your tools along with you in the dark.

Now the floor joists are ready for the sub-floor. This is where you find out why it’s so important to have the foundation in square. You can use plywood or wafer-board (OSB) for the sub-floor. Many Carpenters like to use tongue-in-groove sheets because it has a better fit and the floor is less likely to squeak.

The thickness of the plywood or wafer-board needs to be at least 5/8” thick. Start at any corner and lay the sheet down so it fits tightly into the corner. It will extend to the floor joists in even measurements if you use 16” centers or 24” centers. You can use 8d nails to fasten the sub-floor to the joists. Offset the plywood joints or straddle them for extra strength.



You will also need to cut a vent hole in the rim joist about every 15’ or so to increase airflow and prevent the joists and floor from rotting. Proper ventilation is essential in any when you are planning to build your new home.

Now we can move on to framing the walls.

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