Do Over: Floor, Mark 2

Since part of my goal is to document the process of construction, it’s time to declare my first major oops.  Maybe this will save someone else from doing something pointless and wasting time and money.  Sigh.

I am not happy with my floor implementation.  It feels solid and well insulated, but there are numerous issues with it that have led me to decide to start over.  In the end I expect I’ll waste about $600 and maybe a week worth of labor, but I think the end result will be better.

First, I wanted to nominate Terry S. for the “you called it” award on water.  Even with one layer of house wrap, fully taped, and not one but two 30×30′ tarps tented up and covering the floor, it is still basically raining inside every time the weather turns warm or launches into a downpour that melts the snow.  While I’ve had builders assure me that the water will just run through, and it will dry out, and it will all be fine, I’m not certain enough to trust putting the rest of the house on it without checking.  And checking means starting to peel up the subfloor so I can look inside, and once I start that if it looks bad, I’m going to need to redo things anyway.

But that by itself could just be a bit of maintenance in the spring.  No, there are a lot of other problems that have combined to make we want to start over on the flooring.

  • Elevation: because of the additional 6″ of height added by the flooring (which would of course have been there with SIPs as well) making the home accessible is turning out to be a lot more difficult that I would have liked.
  • Structural: the bottom inlet nailers for the wall SIPs would have been mounted to the floor stack, which itself is not really a tested structural element.  (SIPs would have been better, but not ideal.)
  • Levelness: in my rush to get the floor in place before the winter, I didn’t do a great job of shimming around the I-beams to bring the rim joist level up to the I-beam level.
  • Mechanicals: with the insulation sandwiched between the two layers, any mechanicals (plumbing and electric) going through to the basement would have to be cut through both layers of board plus insulation.
  • Water damage: may or may not have occurred.

So, I’ve come up with a new plan, and by choosing to go forward despite the possibility that the current floor is “sound” (with respect to the water – all the other issues would still stand), I have the opportunity to implement a good fraction of it (the first three steps) from inside the basement during the winter, so there will be less of a scramble to do the added work when spring comes.

  1. Cut 2×8 joists to fit between (and perpendicular to) the I-beams.  Notch these at each to a depth closely matched to the flange thickness of the I-beam, so that when assembled the top of the joist and I-beam will be flush.  (This addresses the elevation issue: subfloor will eventually sit 6″ lower.)
  2. Remove screws from bottom of current assembly.
  3. Insulate rim joists.  (May need to wait depending on other steps.)
  4. Strip off and stack the subfloor boards.  (If the subfloor was water damaged, then it would have needed to be replaced anyway, but if it’s OK I hope to be able to reuse it since I’ll be screwing back down to identically aligned joists.)
  5. Pull out and stack the rockwool for reuse.
  6. Strip off the 2×6 and 2×4 joists and the PIR.  (We’ll have to see what order of operations works best for this.)  Stack PIR for reuse.
  7. Strip off and stack the PT plywood.  (Need to determine if it can be reused elsewhere in the project; otherwise perhaps it will show up on Craigslist.)
  8. Correct the shims on the rim joists to as near flush with I-beams as practical.  (This addresses the levelness issue.)
  9. Finish mounting east and west joists with joist hangars from rim joists.
  10. Reinstall subfloor.
  11. Put off reinstalling insulation until after mechanical work is done.  (This addresses mechanicals issue.)
  12. Install inlet nailers with structural screws to rim joists.  (This addresses structural issue, and is the first step of the work I would have started in the spring anyway.)

It seems like a lot of steps, but it feels like I should be able to do most of them in less than a day.  So far I’ve completed the first eight of the 7′ joists and eight of the 4′ joists, and about 20% of the screw removal.  While I was at it, I also restacked some of the stored lumber in the basement so that it’s not directly under the drip edges.  The time spent has been about 3 hours so far.

Sorry, no photos yet but maybe I can add one retroactively.

Wow, I’m Floored!

For the last couple of weeks it has been “damn the winter weather, full speed ahead!”  And somewhat to my surprise, I managed to get the floor panels I designed (and wrote about here) completed.  Apparently after repeated exposures, my hands finally got used to working in 37°F (2.8°C) weather, and I didn’t feel cold any longer.  My ears were protected by 3M™ WorkTunes™ headphones, which may have been the single best tool investment I have yet made on this project.  Certainly the most consistently utilized, particularly with Spotify keeping my ears happy and not merely warm.

A big ($3000) order of materials was delivered in late October, and I immediately started trying to get the flooring in place.  Zephyr was intrigued.

Curious cat is curious

At first things went pretty quickly.

However, my birthday party happened just a day or two into getting the materials, so it was almost November before I really got going.  Below you can see the bracing ready for the 2x4s to come in above the PIR foam board, and the 2×6’s used for every third span (west side) and for all of the 7′ spans (east side).

Here is some of the PIR foam board in place, 2×4’s across the top and on the braces, spray foamed along edges of PIR, as well as the first batt of rockwool.

And finally here is what it looks like with all the rockwool in place.

Then I started to get the actual subfloor laid on top.  Unfortunately, not very long into this we had our first 4″ snowfall, and thereafter I was spending a lot of time with the shop-vac removing the snow and water that was stuck inside various cavities (either on top of the PIR board, or on the PT plywood bottom layer where the PIR board was not yet laid).  Furthermore, laying the tongue-and-groove subflooring with the appropriate staggered (and thus, diagonal) pattern turned out to be extremely time consuming.

It’s probably worth sharing that the necessary tools for this are one (or more) sacrificial 2×4’s and a sledgehammer.  You lay the 2×4 against the edge of the subfloor plywood (best if it’s the groove side) and whack the crap out of it to get the plywood to move across the glue and into place.  I shattered one 2×4 along the way and beat another one beyond the point of further usefulness.  Also, on occasion, you may want wood shims (used to force the tongue up into the groove) or a wonderbar weighted down with a heavy piece of PT lumber (used to force the groove plywood down onto the tongue).  Or, you could do this with more than one person, in which case, you get someone to stand on the edge to keep it aligned while you whack the 2×4.  This is definitely one of those “better done with a team” jobs.

But, in the end, I managed to get it all in place.  I still want to come back and add the house-wrap to the remaining 2/3 of the floor, to keep water out over the winter, but at least the main job is now complete!

 

Was it worth it to do all that extra complex framing for the 10% improvement in insulation?  I’m not sure – maybe not.  I’m estimating that adds up to maybe 85 BTU/hr or 25W of heating saved, whereas the remaining total loss through the floor is perhaps 875 BTU/hr or 256W.  The R-41 SIPs would have been closer to 553 BTU/hr for a savings of 94W.  (All these numbers may be lower if the equilibrium temperature in the basement is higher.)  But I learned a lot of interesting things along the way.

Time to Build, Less to Write

We’re having a big thunderstorm this afternoon.  Before this, the weather had been good enough for the past few weeks that much of the free time I might have spent blogging about the Little Rental House was instead spent building it.  This is one of the reasons things have been so quiet here lately.  The other is that I sank a whole lot of time into a long, detailed post about rainwater collection, which still isn’t finished, and so what writing I have done hasn’t gotten published.  I promise, I’ll get that one out soon.

In the mean time, a little status update:

  • The basement slab was poured on Aug 5th.
  • I now have all five of the I-beam floor supports in place and bolted down (the photo below only shows the first two).
  • The 1″ insulation around the basement walls is about 60% finished, but has slowed down because I’ve found I need to clamp the boards in place while gluing, and I only built one clamp apparatus.
  • I’ve measured, cut, and started mounting the stringers for the basement stairs.

Finishing up the slab

Staking My Claim

The phrase “staking a claim” started out as a literal description of an activity: marking a piece of land with stakes.  Today, the figurative returned back to its literal roots.  This post is now at the northeast corner of my building lot.

The surveyors went further and put in marks for the corners of the house – actually, offset by 5 feet from each corner to allow room for excavation.  These days, surveying is mostly done with differential GPS (DGPS) which has such remarkable precision that the surveying team was able to determine which of several marks on a nearby manhole (within an inch of each other) was their previous measurement reference.  Taking advantage of this, they put in large (2″x2″) stakes for the house corner offsets, and then repositioned the point of the GPS on top of the stake so they could mark a specific point within that 2″ square and put in a nail at the point.

This then allowed me to run strings (which unfortunately are barely visible in the photo) to mark the actual location of the house.

Today I also received a new excavation quote which is $5,600 lower than the previous one and includes all the materials, which is a huge improvement.

Just as exciting, my friend an neighbor Steve took delivery today of his new tractor, with which he’ll be starting a farm on the east end of our community’s land.

There’s other exciting news on the horizon, but for today I want to get this posted.  Pun, as usual, intended.