Category: First Floor Subfloor

Replacing the existing wonky plank floor with level OSB

Basement Stairwell Framing

March 28, 2014 / / 0 Comments

The subfloor is nearly done. I just have to put down a thin, 4″ strip along the North wall. However, before I can finish that up I needed to fix the stair opening to the basement along the outside wall. When Matt B and I framed it last year, we cut back the joist ends along the outside wall. Now, as with all of the other joists, they need to be at the right level. I took a look at it and decided it would be easier to pull out the joist ends and redo them.

Stair opening

Stair opening (also pictured: giant rack of old floor boards in basement)

I first tried cutting the joist ends down to the right size, but they were not in great shape, and a couple of them broke in half. I tried cutting some new pieces but nominal 2x10s are too loose in the rough sawn notches and I couldn’t position them as accurately as I wanted. In addition, I decided I wanted some sort of bracing down the length. A full 2×10 would close up the cavity and prevent it from being spray-foamed. Notching a 2×4 into the ends would work, but would be a real pain.

Instead I decided to just put new 2x4s (planed a few times) on top of the rim on the other side of the wall studs, screw a 2×4 onto the face, and then for good measure, shore it up with some support blocking glued and screwed underneath.

New framing, start of subfloor

New framing, start of subfloor

With the new structure built, I started working on covering it in subfloor. I wanted the OSB to span the opening, which required some fancy carpentry. The narrow section along the wall needed a groove because the rest of the subfloor is tongue and groove. I’ve been cutting my own grooves out of my leftovers on the table saw instead of wasting full panels. The problem here is that the piece is shaped like an ‘L’, so cutting the groove on the inside edge was complicated by the fact that I couldn’t slide it all the way across the table saw.

I started by cutting the groove as far as I could on the table saw, which left about a foot or so. Then I used my circular saw to get closer, leaving about 4″. Finally I used my oscillating tool to cut the sides of the groove and a wood chisel to finish it up. The piece slid in and fit like a glove, tying this section in with the rest of the subfloor. Once I finish this edge, I just need to plane and glue some seams and this project will finally be done!

Learning Lessons

March 21, 2014 / / 2 Comments

It goes without saying that in a project like this, having never done anything like it before, that we’re going to make mistakes. As they say, the important thing about making mistakes is what we learn from them. I’m trying to learn from what we’ve done so far, both to help inform us on how to do things in the future, but also just as advice to anyone thinking about doing the same types of things.

Fortunately, most of the things that I would do differently have been small: I would use the “Q” column caps with the “SDS” screws for the LVL beam so I didn’t have the stupid through-bolts sticking out. Drilling those bolt holes was an unbelievable pain and furring and drywalling over them will suck. I would have checked for square when re-framing the bay, and done the rigid foam around the bay differently, since I’m not thrilled with the angled corners. However, these are small enough things that I don’t worry about them too much.

The damn subfloor, though. No project has offered so much “learning” as this. If I could go back in time, the steel beam in the basement needed to be about ¾” higher than we put it. When I was jacking up the old beam, I ran into a lot of resistance trying to get it any higher so I made it level where it was. If we had gotten it up a bit higher, the whole joist leveling project would have been considerably easier. Failing that, I needed to shim under all of the joists at the beam (Method 3). I should have held off making the stair opening down to the basement until the leveling was done. I should have brought all of the OSB in right away instead of letting it sit outside under a tarp all winter.

OSB in the snow

OSB in the snow

I needed to plan out the subfloor courses first, since the joists aren’t exactly 16″ on center. I needed to put down chalk lines for each course instead of assuming the outside wall was reasonably straight, or at least use the laser. I should have taken up all of the old floor right away, instead of a section at a time. That way I could have repositioned the joists that were just a bit off in the middle by using blocking. I should have checked the joists for being out of square, so I could plane down high edges.

I should have ripped the tongue off the first course and left the groove exposed instead of putting the groove against the wall and leaving the tongue exposed. Jamming the groove over the tongue when it’s already screwed down is a bad way to do it.  I needed to put glue into the groove before putting the next panel in.

Slow progress

Subfloor

More than anything else, though, I should have hired it out. It would have cost thousands of dollars, but it would be finished by now, probably a couple of months ago. Instead the subfloor isn’t finished, it’s not done as well as it could have been, and most likely we won’t finish the first floor this year as a result. Well, lesson learned. I’ll definitely be hiring out some things going forward to try and get this project back on track.

Bay Electrical Outlet

March 4, 2014 / / 2 Comments

As I was leveling the bay, it occurred to me that before I put down the OSB subfloor, I needed to run the conduit for the electrical box. In Chicago we have to run EMT conduit for all electrical. No Romex wire, no BX armored cable, just hard pipe conduit. Looking at the, er, generous amount of framing I used when we installed the windows, there was no way to run the conduit sideways. The window itself meant I couldn’t go up, and the masonry below made it difficult to go down, but still less difficult than the other options. Regardless, resolving this now, before I put down the subfloor, would be vastly easier than doing so afterward.

Electrical box in bay

Electrical box in bay

Dean came over Saturday and we figured out how to run the conduit with the least damage to framing, brick, subfloor, and spray foam. The box is mounted in the center of the window and the conduit goes straight down before bending at an angle to the left. The shim I put down on top of the brick needed to be cut at an angle so the conduit could pass through, directly beneath the subfloor. Dean notched out the sole plate while I chiseled out a narrow channel in the brick behind the front joist with my rotary hammer and drilled a hole through the joist in the center of the bay.

Conduit bending around brick

Conduit bending around brick

With some careful bending (followed by some not so careful bending) we managed to get the first piece through the joist and the second piece around the channel and up into the wall next to the front door. That meant we could put down the OSB in the bay, which required just a little bit of notching on the underside to fit around the conduit where it curved up into the wall. Now when it comes time to do the rest of the electrical we won’t have to worry about how to put this in without damaging the brand new subfloor.

Bay Leveling

February 27, 2014 / / 3 Comments
Removing floor boards

Removing floor boards

The pre-subfloor leveling isn’t quite done yet, and the bay window on the front of the house brought its own set of challenges. For starters, the joist running across the very front of the house (and across the widest part of the bay) is embedded in brick, meaning I couldn’t jack it up the way I did most of the others. There’s also a gap of nearly two feet between that joist and the joist in the center of the bay, which is considerably wider than the 16″ that most of the joists are spaced. Finally, the old floorboards rested directly on top of the brick foundation and extended under the bay walls, whereas in most of the balloon-framed house, it only reaches the edge of the wall.

Level? ish?

Level? ish?

When we rebuilt the bay windows, I noticed the floorboard situation and debated replacing it then, but between doing only one window at a time and the corner studs not being replaced, I decided against it. That meant the first step was to use an oscillating multi tool to cut the floorboards back at the wall edge. Then I glued shims to the top of the existing joists and added some blocking joists to better support the gap between joists.

Shimmed, Reinforced, Re-mortared

Shimmed, Reinforced, Re-mortared

Questions sprang to mind of how to control air and vapor infiltration through the foundation and through the gaps in the wood, and how to insulate the bay properly. We’ll be spray-foaming the cavities in the wall, and on the sides of the house we’ll spray foam the top of the foundation wall to air seal it to the wood, but here that isn’t an option because the brick comes all the way up to the underside of the floor. The exterior rigid insulation doesn’t help either because it doesn’t extend over the brick.

Front shim and spray foam

Front shim and spray foam

I decided to attach an inch-thick shim to the inside edge of the brick wall (on top of sill gasket) that will support the subfloor. In front of the shim, and along the top of the brick on the sides of the bay, we’ll fill with spray foam. I’ll also glue the outside edges of the subfloor to the framing to further seal everything. Hopefully that will be sufficient, since it will be damn difficult to do anything about it with the subfloor in place.

When I initially test fit the shim I realized that the brick was —perhaps unsurprisingly— uneven. In order to properly support the shim I had to mix up some mortar and straighten out the top of the foundation. That meant waiting a couple of days for the mortar to set up, but then I was able to drill some holes into the brick and secure the shim with Tapcon screws.

First piece of OSB

First piece of OSB

I went through a few cans of “big gap” Great Stuff, since the real spray foam won’t be for a bit. Fortunately it’s so cold that it cures slowly, giving me ample time to even it out. I got the first of three pieces of OSB down that go into the bay. I took my time and worked out the dimensions exactly, accounting for all of the unevenness of the studs. There’s still a small gap along the edge of the angle, but I’ll fill that with caulk. The important part is it’s secure, level, and insulated. I’m considering whether I should exchange the one piece of blocking in the center with two, since that would be a more proper 16″ spacing, plus there’s a good chance I’ll wind up putting an electrical outlet in the floor there. One of the reasons to use screws instead of nails is you can change your mind without too much hassle.

Subfloor Frustrations

February 13, 2014 / / 0 Comments
Leveling joists

Leveling joists

I spent nearly all of this past weekend leveling the joists in the first floor. That effort was largely successful, with the nine remaining 12′ spans all adjusted to within a sixteenth of an inch using Method 3. I also leveled five other joists that required the tapered shimming method and got a few more sheets glued and screwed down. My hope, and in fact my expectation was that having done that I would then be able to start putting down full, 8′ sheets of OSB, allowing me to finally finish up this project.

Using the shimming method

Using the shimming method

Unfortunately, that hasn’t happened. In addition to not being level, the joists are not evenly spaced. They employ a generous “sixteen” inches on center alignment that means the 8′ sheets don’t line up in the middle of a joist at either end, sometimes coming short of one joist entirely. I tried planning ahead, measuring out to the next sheet and seeing if I could make one sheet stretch, but it just didn’t work. Instead I’m finding myself cutting sheets at roughly 32″, 48″, or 64″, plus or minus an inch or so.

Slow progress

Slow progress

On top of this, I’m finding that the walls aren’t exactly even either, so that I’m having difficulty getting the panels to align evenly down a joist and one panel to the next. After putting down an 8′ panel that left a gap at one corner and was snug at the other, I decided I needed to do better. As a result, instead of cutting my panels square at say 48″, I cut an edge that tapers back a ½” or so from the tongue to the groove, so that panels meet in the center of the joist and the tongues fits snugly into the grooves. This is precise and thus time consuming work. Tonight I spent two hours putting two small panels down, incrementally increasing the completed area by a whopping thirty-six square feet.

Cutting tapered ends

Cutting tapered ends

When I finished carefully scribing, cutting, and fitting the second of these panels I discovered that the joist was torqued and the shim I glued down was sticking up on the exposed side. Because of this, the second panel is raised up higher than the first. It’s a slight difference, but after the inordinate amount of time I’m spending to make everything level, it’s extremely frustrating. I’ll probably have to go back around with the power planer and even at least a few seams.

Argh! Not even!

Argh! Not even!

I keep reminding myself how I wanted to hire this project out, and thinking I really should have done that, high cost or no. At this point it’s starting to feel like it would have been worth it, assuming they would have done as good a job. It’s hard to even estimate at this point how long it will take me to finish. I’d like to think I’ve figured out my methods now and it should go faster, but who knows. The bay will bring its own set of challenges and I still have some of the shorter joist spans to level. After that I need to fill in the narrow, 5″ gap all along the North wall. Needless to say, I’m really looking forward to this project being done.