How to Frame a Floor Inside ICF Walls - Part 1

Submitted by Ana White on Thu, 10/06/2011 - 10:46

Now that the walls are all up in the Momplex, we can work on putting the upstairs floor (and downstairs ceiling!) in. 

I've had my doubts about how this whole thing is going to work out ... since back when we put the anchor bolts in the walls. Just to refresh ...
We cut out a pattern to use to cut pieces of the foam blocks out.  We don't want any foam to be between the floor and the walls - a concrete to wood joint will have the least wiggle room.
Then we made a bunch of these up - the wood parts hold the two bolts in, and get screwed to the black fastening strips.  
Here the anchor bolts are ready for the pour.
And then after the pour the wood pieces are removed, and all that's left is an anchor bolt poured in concrete, sticking out.  That's all we get to put the floor on.
Step 1 Diagram
Step 1

First things first, we chalked a line around the entire inside of the Momplex at the height of the first floor. Concrete slabs are notoriously not perfectly level, but the <a href="http://ana-white.com/2011/07/new-boss&quot; title="" target="_blank">boss is always right.</a>&nbsp; You can see this line at the bottom of the photo. &nbsp;This will be the bottom of the floor joists.<div><br></div><div>Are you doubting just how we are going to line boards up with those bolts? &nbsp;</div><div><br></div><div>Me too.</div>

Step 2 Diagram
Step 2 Instructions

A little surgery was performed on a tape measure.

Step 3 Diagram
Step 3 Instructions

Stanley really should come with a few predrilled holes for applications like this!

Step 4 Diagram
Step 4 Instructions

For consistency and accuracy over all the bolts, Stanley is screwed right to the end wall. That way we can get an accurate measurement of the placement of all bolts horizontally.

Step 5 Diagram
Step 5 Instructions

The bolt placement is measured on the tape very precisely and called out.

Step 6 Diagram
Step 6 Instructions

We will be hanging this massive board - called an LVL for Laminated Veneer Lumber and weighing hundreds of pounds - on the anchor bolts. So holes need to be drilled to match the anchor bolts placed in the wall.

<div><br></div><div><img src="http://ana-white.com/sites/default/files/floor-inside-icf-wall-7.jpg " alt="" align="none"></div><div><br></div><div>The horizontal&nbsp;measurements&nbsp;are marked on the LVL. &nbsp;This is then followed by vertical&nbsp;measurements&nbsp;taken off of the string line to find the precise location of all anchor bolts, transferred to the LVL.</div>

Step 7 Diagram
Step 7 Instructions

A spade bit with a precise point is used to start the holes. We finished drilling the holes with a Forstner bit - much easier on both me and the drill. The main thing here is to keep your drill level and plumb as you drill so the holes line up just right with the anchor bolts.

<div><br></div><div><img src="http://ana-white.com/sites/default/files/floor-inside-icf-wall-10.jpg " width="470px" alt="" align="none"></div><div><br></div><div>And just keep on drillin'!!!</div><div><br></div>

Step 8 Diagram
Step 8 Instructions

Before we hang the LVLs, we decided to hang the hangers. Because pounding nails on a flat surface at work height is WAAAAAAAAY easier than pounding nails on a ladder over your head. So the joists are marked at 16" on center, starting on the inside corner, and we nailed the hangers on.<div><br></div><div><img src="http://ana-white.com/sites/default/files/floor-inside-icf-wall-12.jpg " alt="" align="none"></div><div><br></div><div>If you are ever in a funk or just need to clear your mind of stress, grab a hammer - not a nailer, a real hammer - and start pounding. &nbsp;There is something intensely&nbsp;satisfying&nbsp;about using a hammer and nails. &nbsp;</div><div><br></div><div><br></div>

Step 9 Diagram
Step 9 Instructions

Justin and I built supports that are just below the height of the chalk line. That way, we have something to rest this monster on while getting the bolts and drilled holes lined up.

The supports are just screwed to the black fastening strips, and run to the concrete, so the weight of the beam is transferred directly to the slab. We can easily move these supports for hanging all the LVLs.

Step 10 Diagram
Step 10 Instructions

Instead of just hauling the hole beam up, we got one side on the support and then slid it down, pivoted it and got the other side on the support. We are all about working smart.

Step 11 Diagram
Step 11

And the bolts slide right through the holes!

Step 12 Diagram
Step 12

And of course we dig out an impact driver normally used for changing tires and other mechanical needs to tighten up nuts on the ends of the bolts.

Step 13 Diagram
Step 13

Once the LVLs are up, we put the rim boards up on the sides that only have single bolts. Rim boards take the place of your first and last floor joist and are part of the flooring system.

The excitement over another step - and a big heavy one! - being completed is short lived. Because now of course I can't wait to see floor joists being dropped into those already set hangers!

Happy Building!

Ana

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