Building the Momplex with ICF Presentation

Submitted by Ana White on Fri, 03/22/2013 - 12:07

A few months back, we got asked to talk about building wiht ICF/ARXX blocks for the Momplex at our local home show. It's hard to believe today is the day! Time really does fly when you are building, doesn't it?

The presentation will be held at the Fairbanks Home Show at 5:45PM tonight (Friday, March 22, 2013). We'll be there to answer questions and chat afterwards, and we plan on checking things out on Saturday as well, so if you are local to the Fairbanks Alaska area, we'd love to meet you!

And since I'm guessing most of you aren't local to the Fairbanks area, I wanted to share our Momplex Presentation with you as well! I know some of you have been following (cheering!) along from the beginning (thanks!) and will recognize the steps and photos.

And for those of you new to the Momplex, I hope you enjoy this quick recap of the last two years of building with ICFs!

Step 1 Diagram
Step 1

That's us! With your encouragement, we went from a crazy dream (ok maybe not as crazy as your mom and mother-in-law living in the same building) to a reality!

Step 2 Diagram
Step 2 Instructions

We really are just another Alaskan family. We eat moose and salmon and when we can't find a babysitter, well, the baby helps too. Life is pretty much DIY all the time.

Step 3 Diagram
Step 3 Instructions

And like most everyone up here in Interior Alaska, we are always building something! This is our house being built way back in 2005. We live in this house right now.

Step 4 Diagram
Step 4 Instructions

After our house was done, we started getting the building itch (I call it the "buildies") again. The Ram and I had a conversation about where we wanted to go next with our lives. He mentioned a lifelong dream of becoming a private pilot and investing in an airplane. I wanted a bigger house with work space and closets. Our little DIY house is just 1124 square feet. We love small, but now working from home has turned small into tiny.

But there was one thing I wanted more than a dream home, or any personal dream I may have. I told my husband that before we did anything, I wanted to build my mom a nice, modern, low maintenance, energy efficient home.

And guess what he said?

The Ram said, "I guess we are building a duplex, because I want the same thing for my mom."

And that's how the Momplex dream came about.

Step 5 Diagram
Step 5 Instructions

For our moms, we purchased a hillside lot with a view of the Alaska range. But up on the hillside, there can be hurricane level winds. Neighbors tell stories of BBQ grills being blown through french doors and roofs being ratchet strapped down in fierce windstorms.

So we decided to look beyond traditional stick framing.

We ultimately chose - with your help - ICF construction. ICF stands for Insulating Concrete Forms. You stack up foam blocks that look like giant legos, and then fill the centers with concrete. We loved the solid concrete core to prevent windchilss, the higher insulation value, and that building with ICFs was four steps in one.

But most of all, we loved how DIY friendly the ICFs are. Even our little preschooler could (and did!) help out!

Step 6 Diagram
Step 6 Instructions

If I can say anything in hindsight, it's this: Plan. Plan everything. When you build with concrete, forgetting a gas line or a exterior box is an all-day ordeal of drilling through concrete. Plan everything. And then double check your plans.

The other thing is to build WITH your materials, instead of fighting everything. We did modify the dimensions of the Momplex so it's exactly 11 blocks by 11 blocks. Why cut every single block?

Step 7 Diagram
Step 7 Instructions

We broke ground Summer of 2011. The Ram rented an excavator and we just went for it!

Step 8 Diagram
Step 8 Instructions

Then it was time for footers. We opted to pour the basement slab later on inside the ICF blocks so we would not have to go back and insulate the slab. Also, the foam ICF blocks act as an expansion joint, so if the concrete expands, it just pushes into the foam.

The boards used for these footers are later used for the scaffolding, and then cut up and made into stair stringers.

Step 9 Diagram
Step 9 Instructions

We went with ARXX blocks because of the support system that comes with it. Yes, I do mean support as in a bracing system to hold the foam blocks in place when you pour concrete, but I also mean the friendly support of real people. The ARXX blocks were actually delivered right to the build site!

Step 10 Diagram
Step 10 Instructions

For the first course, we snapped lines on the footers and just started stacking the blocks. Where two blocks join, we zip tied together the webbing on the insides.

Step 11 Diagram
Step 11

And then we placed the second course on top. Once you have the first and second course done, interlocked together, you then just use it as a pattern as you go up. All odd courses match, all even courses match.

Step 12 Diagram
Step 12

For windows, we ripped 1 1/8" plywood into strips and built window bucks. The bottom of the window buck is 2 treated 2x4s with a space in between for concrete placement.

Step 13 Diagram
Step 13

Doors are done the same. See the blue foam? It's ripped to the width of the hollow interal part of the ICF block. This prevents concrete from escaping and adds insulation around the door.

Step 14 Diagram
Step 14

Since the Momplex is actually two stories, we need to put anchors in the wall for attaching the second story floor to the concrete core. We made up a pattern and traced it on the walls and then cut out the foam.

Step 15 Diagram
Step 15

Then we attached J Bolts to wood blocks and screwed the wood blocks to the walls over the cut out foam pieces.  

The wood blocks get removed and replaced by a ledger board later on.  This way we've got the ledger boards anchored into the heart of the concrete.

The decks are done the same way.  Then we can just bolt the ledger boards on.

I lost track of how much rebar we put in the Momplex.  Rebar is placed in corners, horizontally, vertically, and then extra around openings and over openings.  There is literally tons of rebar in the Momplex.  Tons.

We chose to work with ARXX because of this bracing system.  It holds the walls level during the pour and also provides a scaffolding system for placing the concrete.  

The day before the pour, we were so stressed making sure everything was  in order and we were fully prepared.  Now we are just waiting on mud!

We've poured concrete, but not like this.  Not 11 feet of concrete.  I was definitely feeling apprehensive!

If you do ICFs, a pump truck is pretty much a must.  

We had three people on the scaffolding.  The Ram on the hose, Grandpa Tim using the concrete vibrator to make sure there are no hollow spots, and Grandpa Tim's friend Nick helping with hoses and wires.

Everything went smoothly!

Right after the walls were poured, we poured the basement slab.  

And then it was time to start stacking blocks upstairs.  A little experience under our tool belts now, things did go faster ... until the weather changed it's mind.

As the last blocks went up, we battled snow and freezing temperatures.  

Finally, the last concrete pour upstairs!  This was a huge relief.  Although at this point we are still hopeful to get a roof on before winter, getting the blocks poured was do or watch the blocks get blown off or deteriorate in the elements.

Even the littlest members of our family helped out.  

On top of the final row of blocks, we anchored top plates into the concrete.  We were hopeful to start stacking trusses on them .... but that would have to wait until next spring.

We waited the winter out, and come spring, we put the roof on.  The trusses are tied directly into the top plates, which are anchored to the concrete poured inside the walls. 

It was always a comfort to know after the doors and windows are in and the ceiling insulated, the Momplex will hold heat.  The ICFs are four steps in one!

Knowing we could always work inside, we spent last summer working outside on the Momplex.  Siding is pretty easy because there's a fastening strip every 8".  But the Momplex is big, and our little family DIY crew small, so it did take a long time!

And then it's time to move inside.

Putting electrical boxes in the walls was super easy.  A hot knife just melts out the foam and the box itself is anchored to concrete through the back.

The Ram made a special chain saw for cutting out the channel for the electrical to run in.  What a mess it made, but it sure was quick!

Since the walls are foam, hanging stuff is a little different than stud walls.  So we put metal shingles up above the windows to support curtain rods.

Finally, drywall time!  We've been doing drywall for the last couple of weeks.  

When a room is done, you'd never know the difference between a stud wall or an ICF wall!

Expect hopefully when we get the heat bill!

We are very pleased with the entire experience, and would definitely recommend the blocks for exterior walls.  

And if you are in the Fairbanks area, we'll be taking your questions directly - but feel free to ask questions here too - we'll be doing our best to help you make your best building decision too!