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Thursday, August 22, 2013

Basement Framing Tips

I had a few people ask for some additional information on how we framed our basement bedroom and some of the good, bad and ugly things to look out for.

Disclaimer: This is only an account of our experience.  Check your local building code and city, county, state ordinances to make sure you are in compliance.


So what I've done below is try to illustrate both the existing basement construction make up and the partition framing we built.

The following illustration is a representation of what the basement looks like from the top down.  So if you took the flooring and sub-floor off, this is what you would see.  This is important to understand because due to the way we framed the walls, a lot of the strength for the partition walls comes from the ceiling (or the main floor joists).

Something of particular interest is how the wood on top of the foundation sticks out a few inches into the basement.  So if you go into the unfinished portion of the basement and look will see wood overhanging the concrete by a few inches.  When you frame the walls, it is easier to run the top plates of the new partition walls butted up against these plates and attached to the floor joists above.  This does leave a gap behind your new walls but allows for the insulation that RH installs.  The tricky part is to ensure the walls are plumb from the top to the bottom.  More on that below.


This graphic below is a side view of the same illustration above.  You can see in this illustration how the main floor sill plates stick out over the foundation.  Also note how the main floor joists sit on these sill plates and extend over the 2x4 nailers resting on the steel beams.  At certain points these floor joists will be doubled and sometimes at the beam junction will have a new joist extend out to the foundation wall on the other side of the room (See Main Floor System Illustration Below).  This is important to note when you are hanging your drywall because the nailing points will shift left or right 2.5".  Spoiler Alert!  When you can't figure out why your drew a straight line across the sheet rock and for some reason you aren't hitting anything.

In the illustration below you can see how the floor joists are overlapped to span the distance from one side of the room to the other.  In some RH models they used engineered joists that do not have to do this.  In mine they do.  Just note this anomaly before trying to hand drywall on your ceiling...or you will be sorry.  That stuff gets heavy and your arms get really tired when trying to locate nailing points.

On to the good stuff.  In the illustration below you can see the location of a newly built partition wall from a side view. 

NOTE: It is important to note the Pressure Treated wood used on the concrete floor.  Moisture is still going to wick up and gather around the bottom of your foundation and slabs.  RH uses a thin piece of a plastic based product.  I'm sure they sell it somewhere and in sheets larger than we had the time or energy to cut.  PT works great and lasts long time... reference the outdoor decks still standing despite harsh weather's best efforts. 

Building the wall:
In traditional framing you would build a wall on the floor and then stand it up.  There are two assumptions in this methodology.  1.) The floor is flat and level.  2.) There are no obstructions above the wall you are trying to stand up.  In the case of our basement...we did not meet either of these criteria.  So we opted to build the wall in place, piece by piece. 

I'll go into a bit more detail below but here was the sequence:
- So we located and attached the top plates
- Cut a few studs to approximate size to help locate the bottom plate
- Dry fit the bottom plates
- Attached the bottom plates
- Added all the studs

Locating the top plates:
Another spoiler alert!  Do not make the assumptions we did. 1.) That the main floor sill plates are straight and present an even reveal all the way down the foundation wall. 2.) That the floor joists are all at the same height and 3.) That the top plate you are attaching to the floor joists are all straight and not crowned, bowed or twisted in any way (See illustration below).

Ideally you would want to just snap a chock line across the bottom of the joists to ensure the top plate will be straight.  The problem with this is finding your chalk line in a garage full of a mountain of both full and empty boxes but not finding chalk.  So with a little Kentucky windage, some head scratching, various placement of a 4' level and here is where the plate is going to go.  Looking back I would have stopped the operation and got the chalk.  If you have a bowed top plate, it will be taken out by screwing it to the problem.  Likewise, if you have a crowned top plate, you can pull it straight to a reference line and then the wall will be straight and not curved.  Ahhh, but you need a reference line.  We lucked out because we tried not to use any of the crowned boards.

We screwed the top plates to the floor joists using 3" Coarse drywall screws.  DO NOT use Fine drywall screws.  They don't grip as well and tend to spin and strip out the wood.  You can use deck screws of stainless steel or galvanized too but they are more expensive and do not add any additional advantage to inside construction.

The best tool we I have ever owned.  Because I couldn't find my drill, I went and bought a new set.  Actually it was a bonus pack where a compact 12v drill/driver, just happened to come with the larger drill.  This was ideal for sinking both the 3" screws and the later the drywall screws.

Locating the bottom plates:
So now we had the top plates screwed to the floor joists above.  We just set the pressure treated bottom plates approximately where they would go.  Then we took a few measurements, starting at one corner and working out way out.  NOTE: There is a good chance the bottom plates will not be sitting flush on the floor due to the unevenness of the basement slab.  You can stand on the board to try to push it down but it probably will not budge.  Cut the first one a little tight...knock it into place to push the bottom plate down and then take your second measurement.  Keep doing this until you have reached the end of the bottom plate (2' on center...see illustration below).  If the studs are cut tight enough, friction will hold them in place.  Remember, the bottom plate will curve both up and down with the slope of the basement slab.  So you want to cut these a little tight and then trim a little at a time until you get the right fit.  This will help keep the bottom plate in place during a later step.

Tip: While the wall is assembled...scribe each stud and it's corresponding location onto the top and bottom plate.  It will make it easier to put them back in place later.

Now that the wall is rough cut and dry fit together, you will want to take a level and put it on the front of each stud.  You will kick out the bottom plate until it is plumb.  Work your way down the wall, checking each stud.  You may have to get some leverage between the bottom plate and the concrete wall behind it.  Once you get to the end, go back and check a few points to make sure things haven't moved.  A few gentle taps with the hammer should get it dialed in.  Once you are happy that the wall is straight and plumb.  Scribe lines on either side of the PT bottom plate onto the concrete slab.  You will need this reference line in a few minutes.

Things to think about at this point:
At this point, you also should start to think about how you are going to hang your drywall.  Depending on the sheets you buy (8', 10' and 12' lengths), you should start looking at where it is going to land.  Remember these walls aren't structural, so if you have to cheat over a 1/2' or so to get keep from cutting a full sheet and adding another butt joint to tape, then it is to your advantage.  We did add quite a bit of blocking in places to make it easier to hang the drywall but with good planning, you can minimize this.

Attaching the bottom plates:
There are a few options for attaching these bottom plates to the floor.  1.) You can drill holes in the concrete with a masonry bit and installed what are called Tap Cons (brand name). 2.) You can shoot concrete nails into the ground with a tool that uses .22 caliber shells or 3.) You can use a Heavy Duty water resistant Liquid Nails product.  I'll give you one guess which way we opted for.

If you remember, you're wall has been dry fit together.  So take the studs out of the wall keeping them in order that they will go back in (you can even number them if it helps).  Flip the pressure treated piece of wood over and make sure it doesn't have any dirt or debris on it.  Also note the lines you scribed on the floor.  Make sure it is clear and clean as well.  You don't have to wash it...and besides you don't want to lose those lines you drew.

Liquid nails (a brand name for a type of construction adhesive) comes in tubes that require a caulk gun.  Both of these items are inexpensive, easy to find and use.  Usually near the paint isle.  The PM will go over a laundry list of preventative maintenance you will have to do to your home to keep it in good shape.  On this list is putting various types of clear and white silicone caulking throughout.  So you will get lots of use out of it.

Once you have the caulk gun, and liquid nails in it...apply a bead of this glue onto the bottom plate in a "S" formation.  This will ensure you get even adhesion.  When you flip it over, line it up with the lines you drew and lightly slide the board back and forth an inch or so.  Not a lot just enough to get the glue to spread and grab.

Installing the studs:
Now that you have the bottom place glued in place, you are ready to start installing the studs.  Place the first stud in place, check the line on the floor and verify plumb.  You will attach each stud, one at a time until you reach the end.  See below for attaching the studs.

Attaching the Studs to the Top and Bottom Plates:
Again, there are a few options here. 1.) Use a hammer and nails.  This poses a bit of a problem because you are building in place and the hammering motion can move the studs off the mark.  The wall isn't structural but it helps if the wall is both plumb and level when you hang the drywall. 2.) Shoot it with a nail gun (if you have one) or 3.) Screw them in place with 3" drywall screws (or others, your choice).  We chose the later.

A note on how to toe nail:
We found it much easier to toe nail the studs to the top and bottom plates using screws and cordless drill/driver than trying to hammer them.  If you are using 3" screws and you angle the screw up through the stud into the top plate or bottom plate, you should be able to get about an 1" or so of grip in the other piece of wood.  Sink 2 screws in the top and 2 in the bottom.  These fasteners and the friction of the tight fit should give you a sturdy wall.   Also, note that you can toe nail the stud from the front but know that if you don't sink the screw all the way, it could interfere with hanging drywall.  When you sink all the screws into the drywall it will probably overcome this but it could create some issues.  We had to do this on a few occasions but it was because the stud was a bit loose and moved around a bit.  This was a quick way to get it set in place to come in from the side and finish toe nailing it. See the illustration below.

A note on the RH insulation:
My PM had mentioned to us during our pre-settlement walk-thru that the insulation they put on the unfinished side of the basement has a moisture barrier on the outside.  He also mentioned that with the waterproofing on the outside of the house, any moisture that gets back there is trapped and can't get out...leading to mold and potential foundation issues with he freeze and thaw cycles.  he recommended before we sheet rocked over the walls to cut slits in the barrier to allow the insulation to breath and exhaust the moisture.  Our dehumidifier will pull this moisture from behind the walls and down the problem.

We have taken a short break from drywall finishing and have been tackling other smaller projects.  We will get back in motion on finishing this project and depending on whether anyone sees value in this type of post, I may do something similar on our experience, wiring, drywalling, taping, mudding, texturing, etc.


  1. That was exactly what we need. Are your ceilings in the basement 8 or 9 feet?
    Thank you so much!!!

    1. We have 9' ceilings and used 10' studs, then cut them to fit.