As I mentioned in a previous post, we said to hell with Trex and decided to make the decks attached to the back of the house and our master bedroom a little more stout.

Each deck is supported by a total of six concrete columns, each with steel reinforcement at the base (’L’ shaped pieces that extend into the slab below) and vertical rebar through the center of each column.  Doug got several lengths of 6 and 8 inch steel in various shapes - C metal, Z metal, and receiver channel.  The C’s and Z’s look just like they sound, and the receiver channel is the same shape as the C but with a flat flange and just a bit larger, designed to fit over the C metal.

We measured and cut a large square out of the steel, with one piece of steel on each edge of the square.  It took a bit of coordination and ladder prowess, but before long we had the elevated square held in place with some small welds - the corners welded together as well as a few welds to hold the steel to the rebar sticking out of the top of the columns.

Each piece of steel got another beam attached to it for reinforcement, and we cut four lengths of the Z metal to run perpendicular to the house and provide additional support.  Each of the welds were cleaned and painted, and before long we had an impressive frame.

To cover the surface we cut sheets of metal decking to length, and laid them on top of the frame with a short overlap in each one.  This decking will hold the concrete when it is poured, and will comprise the temporary ceiling of the patio below.

We had been planning this for a while, but wanted to give the framers a surface on which to stand so they could build the roof over the deck.  To support the outer corners of the deck, we screwed some angle brackets that ran about 24″ out from each front corner, and they used stout 20′ boards as braces supported by the angle brackets.  We will build an outside edge for the deck, pour the concrete, and replace their temporary roof supports with the permanent columns on each corner of the deck.

I had originally planned to run some Pex tubing through the slab to be able to warm it to melt ice and snow, but I’m not crazy about having to drain the loop every winter. I’m going to look into the electric heaters that they use in bathroom floors, and see if it would be cost feasible to use those instead.

Here are a few pictures of the structure….

After a fairly long pause in major construction, Mike’s crew arrived and started slinging lumber.  In about a week and half they completed all the interior walls on the upper level, and made it most of the way through the ceiling joists and rafters.

The amount of precision in their measurements and cuts is pretty amazing considering the speed at which they go.  I’ll go into more detail on some of the more interesting bits in a later post, but wanted to get some pictures up.  Having the roof line established really defines the shape of the house.

They will finish up the roof deck hopefully Monday, and then Jeff and his crew will come out and put the tar paper and underlayment down in advance of the actual roof being put up.  Having it dry inside will be a huge step forward.

Not long ago we pulled the stair treads out of their forms.  They didn’t look too bad for the first official try, but the concrete was too dry and as a result there are a lot of voids in the surface of the treads.  We sealed a couple of them and it darkened the color quite a bit - they turned out to be a light brown color.

We’ll give it another go with a slightly richer mix (by adding some additional portland cement to the bagged concrete) and a little more water to see if we can get the faces smoother.

The foam that the ICF blocks are made of is fairly vulnerable to damage from impact (e.g. getting hit by a board or rock) as well as from UV damage.  Nearly all of it will be covered by the siding on the outside or drywall on the inside, but there is a small strip just above the grade that will be left exposed.  This is by design, as even though we are using cement fiber siding it is not advisable to fill up onto the siding and thereby bury the bottom edge of the siding.

In order to protect this strip, we started applying a product called Dryvit. I’m not sure about the chemical makeup of Dryvit, but you mix together a half of a bucket of Dryvit with 1/3 of a bag of Type I/II Portland Cement.  This creates a fairly workable mix that can be spread with a trowel.

To apply it, we spread strips of it vertically every 18 inches or so along the surface to be covered.  Then a strip of fiberglass mesh 24″ high is stretched out along the wall just above the ground and embedded in the strips of wet Dryvit.  Pressing the mesh into the surface with a trowel serves to hold it in place, and then you go back and cover the whole area with Dryvit, smoothing with a trowel as you go.

It sounds a bit easier than it is, and since it is a cement-based product, the length of time since it has been mixed and the temperature makes a big difference in how difficult it is to apply and smooth out.

One very important step is to remove the top layer of foam to make sure there is a clean surface to adhere to.  This can be done with a long handled broom or something similar.  The reason I know this is important is that I forgot to do it on the first wall that I did unsupervised by Doug, and he was able to easily peel it off a few days later as a result.

This is not terribly difficult to do, but is fairly difficult to do well so that the surface is smooth.  I can’t remember too many house projects that I’ve done so far that have made my arms quite so tired.  We still have quite a bit left to go, and it will need to be completed before the house is wrapped with Tyvek and the siding is put up.

One of the constant background projects we have is extending the concrete driveway toward the house. We try to keep roughly sixty feet of forms set up at any given time so when the opportunity comes up we can extend it. Forming a driveway is about as simple as it gets, but it takes a little practice.

The first thing we did was stretch a string line down the North side of the driveway. One stake was driven at the top, and another down the hill with a string stretched tightly between them. This provides a visual reference for keeping the side of the driveway straight. Then another metal stake is driven so that the center of the board will line up with the string, and a 2×4 is nailed to the stake at the desired height. Each 20 ft. board has three or four stakes to support it, and to connect two together you just hold the ends together and toenail them.

Once one side is straight, we take a spacer board whose length is the desired width of the driveway, and stake and attach the boards on the opposing side in the same way, making sure that the distance between them matches the length of the spacer board.

The distance of driveway poured is determined by the amount of concrete as well as the thickness of the slab (the higher the form boards are raised, the thicker the driveway will be). The spacer board becomes a floating end which is dropped in where the concrete runs out.

Doug has a magnesium screed board that is rested on top of the forms and dragged along to create a level surface. Having the right amount of concrete is a bit of an art, as trying to drag too much wet concrete with the screed board will wear you out quickly.

Once the surface is relatively flat, a bull float is run over the surface to smooth it out. This also reduces the surface area of the driveway, which will slow down the drying time and give you a bit more time to work with it. When it is still a little wet, we run an edging tool around the top of the forms to soften the top edges of the driveway, and cut joints every 10 or so feet with a handheld jointer. The joints give the driveway a natural surface to crack as it cures and shrinks, in order to prevent ‘unplanned’ cracks in the surface.

The final step is to broom the surface with a large flat broom head. This adds some texture to the surface to keep it from being too slippery. Once the concrete sets up (generally by the next day) you strip the forms, pull the stakes, and extend the string line if needed and set everything up again at the end of the slab.

The degree of difficulty is influenced quite a bit by the consistency of the concrete, and concrete that is too dry can be really hard to move around.

So far we have done about 150 feet with several hundred to go. Here are some pics of what we have so far.

On Tuesday my friend Grant came by to say hello and check in on the progress at The Casa. He made a comment along the lines of ‘that doesn’t look like any framed house I’ve ever seen…’ Since I have heard that several times since starting the project I thought I would take a minute to explain what Insulating Concrete Forms (ICF) are and how they work.

Although it is not yet widespread in our area, ICF represents a whole new set of options for new buildings, including residential construction. ‘Stick built’ or wood framed construction is still the prevailing choice, and it seems that most of the subcontractors are so accustomed to working with wood framed walls (read: they can do their work very quickly without a steep learning curve) that they don’t want to do anything but that. There have been some very welcome exceptions to that to be sure, and I’m sure in time more of the trades will continue to focus on this new building trend.

Even construction with brick or stone, like my father’s house, is essentially a facade applied over walls constructed out of (mostly new growth) timber. This is necessitated by the relatively low insulating value of brick or stone on their own. They are all fairly good thermal conductors, meaning that temperature changes on one side of the wall will be relatively quickly transmitted to the other side. The use of fiberglass or foam in the stud cavities of wood construction allowed houses with masonry construction to improve their insulation factor.

Decades ago a primary limiting factor for the use of concrete was aesthetics. While construction with concrete reinforced with steel was fairly cost effective and enjoyed more longevity than the average wood framed house, overcoming the ‘ugly’ factor was an issue. More common in commercial construction, penetrating the residential market was difficult when the primary option was to paint the concrete walls (or leave them bare). Couple this with the fact that concrete alone is also a very good thermal conductor, and it is no surprise that there remained relatively few concrete houses.

These insulation and aesthetic issues are both soundly addressed through the use of ICF construction. There are a number of different manufacturers of the blocks (Logix, Fox, Nudura) but all employ an elegantly simple approach. Instead of a single-layer concrete wall, or a layer of wood frame covered with a brick or stone veneer, Insulating Concrete Forms consist of three layers. A standard steel-reinforced concrete wall is sandwiched in between two layers of rigid foam insulation. The materials themselves are cost competitive with standard construction, and the systems are arguably more simple to construct than standard stick-built homes.

The standard building block (in our house at least, built with Nudura) is shown above. It is 8′ long and 18″ high. The inside and outside is made of rigid foam between 1 1/2″ to 2″ thick. The top and bottom of each form has teeth (like Legos) that allow them to easily fit together to build up the wall. In the space between the two sheets of foam are rigid plastic webs that space the forms apart in addition to providing an easy place to snap in the steel reinforcement (rebar). At the top and bottom of each plastic web are small plastic teeth that click together when you assemble the forms. These teeth keep the forms from ‘floating’ apart when they are filled with liquid concrete. These straight pieces are combined with corners and t’s (all with the same interlocking components) to essentially form the negative wall space. Once the forms are assembled (an incredible variety of shapes and configurations are possible by combining different forms) you literally pour in concrete from the top to form the core of the wall. The foam remains in place and becomes a permanent component of the structure of the building, providing a huge insulation boost among other benefits.

Concrete construction that doesn’t use ICF involves building the forms, pouring the concrete, and removing the forms once the concrete has cured - which adds labor to the process and takes away from the r-value of the finished product. So regardless of the system you choose, you wind up with a simple mechanism to build the forms (anyone who can assemble legos can put blocks together), great insulation for the walls, a good vapor barrier to prevent moisture from coming into the house, as well as ideal surfaces on the interior and exterior to attach siding or drywall. I can’t speak for the other systems, but Nudura has a nailing strip that runs vertically every few inches, and acts just like a stud in a wood framed house - allows for trades to drive nails or screws.

There is a great deal of information about and discussion on the benefits of ICF construction just a Google search away, but there are a few that helped us make the decision, including the low cost of heating and cooling, sound insulation provided by the thick walls, and best of all no wood to decay and need replacing down the road. Additionally, while the expansive pale green walls may look a bit odd to folks like Grant right now, by the time the construction is complete and the siding is applied the house will be virtually indistinguishable from a traditionally constructed home.

Hopefully that is helpful in understanding ICF construction, please don’t hesitate to ask if you have any questions or I can clarify anything.

Monday overnight there was a bit of rain, and it raised some concerns in Doug’s mind regarding the newly poured and sealed front porch.  He sprayed some water on the surface, and the amount of fall from the part of the porch closest to the house to the outside edge was not enough to keep water from running back toward the house.

We spent about a half an hour staring and thinking and reviewing options.  We could have the surface polished down, with more taken off the front edge than the back.  This could work, but it would be very expensive and would cause a significant difference in appearance as you moved away from the house due to the amount of aggregate that would be exposed by the grinding off of layer after layer on the front of the porch.  Alternatively, we could try to minimize the amount of water that would fall on the slab by carefully arranging the roof overhang, and caulking around the front door.

In the end, we decided that a fight against the elements (especially water) was not one the house would win in the long run.  Enter the sledgehammer.

I cringed a little bit upon the first swing, and even more when I realized that the blows from the huge hammer did little but make small dimples in the surface of the porch.  The ’state mix’ did indeed set up and get very hard very fast.  We tried for perhaps another 30 minutes with little progress before the next load of concrete was on the way.

We took a break from demolition and filled the holes adjacent to the master bedroom with concrete, and dumped out enough on the ground to fill the four additional short columns there that will support the master bedroom deck, and more around the back of the house to fill the three columns on the back patio.  I thought filling a bucket with concrete and hoisting it up to pour into the front porch columns was difficult, but adding eight steps up a ladder to the mix to reach the top of the 10′ tubes was yet another level of complexity.  A few hours later brute force prevailed, and all the columns were filled, leveled, and plumb with the house.

We then returned to demo, and made a little more progress when we raised the front edge of the porch with a hydraulic jack.  Raising the slab (as much as 7″ thick in spots) off of the gravel bed put a lot more stress on the slab and kept the force of the hammer blows from being diffused.  Bit by bit we chipped away, with the progress getting easier and easier the more of the slab we removed.  I got a good lesson in the power of steel reinforcement, as the rebar and remesh that was added made the removal of the slab nearly impossible in spots - the concrete literally had to be pulverized before it could be removed.

We didn’t finish until Wednesday morning, and not long after we had another load of concrete (this was ’shot-crete’ with fibers, designed for spraying on walls) arrive.  Doug had set up some forms at the beginning of the driveway, and we poured a slab about 40 feet long of varying thickness.  The driveway pour was relatively un-complicated, but allowed me to practice my burgeoning skills a bit.

A little rain at the end of the week was not unwelcome, all the hard work tearing out the porch left me feeling like I had been hit by a truck.  The framers should be here early next week with any luck, and the latest word from Micah is that we should go ahead without him.  He can polish around the walls if they are there - this will be more effort for his crew, but he didn’t want to hold us up any more.  The other benefit is any scuffs or minor damage inflicted by the framers or roofers can likely be polished out closer to the end of the construction.

We moved from our house in Kansas City on Saturday after a fairly brutal week of packing, cleaning, and little sleep. My advice to anyone considering moving ever again in their lives is start throwing or giving away things immediately.

Sunday we completed a few more miscellaneous tasks to get ready for some more concrete on the front porch and for the deck off of our master bedroom. We placed some 2×6’s to make the face of the front porch, and re-chalked all the lines to mark the eventual top of the surface. Once that was set up Jill and I caulked the inside of the form to patch up a few rough spots as well as to soften the lower edge where the lip of the top level will hang over the facing wall.

Additionally, we marked the location of the three more pillars on the back patio so that when we get another load of concrete we will be ready to fill them up to the right level. There will be six short pillars under the master bedroom deck, so we also dug four more holes that will eventually be filled with slugs of concrete to provide a footing for the columns.

It was fairly slow this morning, we started by getting the driveway forms started and standing by for a load of concrete. Sure enough later in the morning, we got word that three yards of ’state mix’ (a very rich mix used for the construction of roads by the state) was on the way. The only bad news is that we would need more than three yards if the entire remaining void of the front porch was to be filled with concrete. Doug got his tractor, and we leveled out a few loads of gravel so we would need about six inches to reach the top.

In an a great stroke of good fortune, the creamy, incredibly strong concrete proved to be just enough to complete the slab, we only had about a quart left over.

A few hours later we came back to seal the slab, and stripped off the forms so we could seal the face as well. The top portion which will be exposed looks fantastic (and just like our current bathroom concrete countertop), and the rougher face below will be covered by a step and some tile to match the surface of the flagstone patio.

I finally got in touch with Micah, and as expected he had been consumed by another job. He suggested that we go ahead and frame the walls and that he would compensate us for the extra expense of having to hand-finish the areas in the smaller spaces (closets, etc) once the walls were framed. I’m not entirely certain how we will proceed there, we are currently weighing the pros and cons of waiting against the somewhat unpredictable schedule of his crew and some of the other subs.

I’m in arrears for a few pictures, please enjoy…

We had planned for a relatively slow weekend to catch up on some paperwork, but got a lot more than we bargained for. On Saturday we spent a lot of time discussing the front porch and how we wanted everything configured. The original specification provided by B&G on the blueprints was (as we requested) closer to a Colorado ranch style, with a lot of stone and square timbers.

The more we talked about it, the less sense it seemed to make to have that kind of an entrance, especially the exposed wood beams given the other design decisions we’ve made over the past few weeks. So, given Doug’s proclivity toward portland cement and how much we loved the way the concrete columns at the back of the house turned out, we opted for a more…ahem…permanent solution.

I headed to Lowe’s and got two 12″ sonotubes (these were the Quikrete brand, colored bright yellow), and we measured the correct distance from the front door and from the walls on either side of the entrance. Soon enough we had big spray painted rings marking the eventual location of the columns. They will stand 7′ from the front wall of the house, and the top of them will be about 30″ off the height of the patio. As a means of paying homage to our current house, we will top each one with a stainless steel column to support the overhang of the roof. You can barely make out the column on the front porch here:

There will be one step down from there onto a flagstone patio of some type.

From there we started talking about the deck on the back of the house, and in case you’ve not noticed the trend just yet, wood is very much the exception at this point. We were planning to go with Trex to keep the need for maintenance as low as possible, but having wooden beams as the infrastructure means we would still be prone to all the cracking, warping, and other issues with lumber.

So a few hours later we had fully baked a design change that involved pouring three more concrete pillars (8″) in closer to the house, and framing the rectangular part of the back deck in steel. The deck will essentially float on the six columns, potentially with some small anchors to hold it to the house. Once the steel is framed in, we will run a short loop of pex tubing and pour probably 4″ of concrete to comprise the surface of the deck. I doubt that we will heat it much, but probably just enough in the winter to keep the snow and ice melted.

The deck off of our master suite will be essentially the same, and we will have a catwalk of some sort in an “L” shape to connect the two together. I doubt that the catwalk will be concrete, and I’m not even sure if we will do that part in the short term.

These changes required us to provide a little more infrastructure for the framers than we originally planned, so we went ahead and built the forms for the back patio (out of the walkout basement) as well as the front porch. The back patio was pretty simple, just a big square with the right level of slope away from the house and a little bit of steel remesh dropped in for support. I also wrapped each of the existing three columns with one turn of sill sealer, which is a thin layer of foam. This will give the concrete a little room to expand and contract without the columns and the patio putting too much direct pressure on one another. After that I wrapped each column with Glad Press n’ Seal wrap to prevent any splatter from getting on them. Holla for new uses of kitchen products!

With the back patio poured, the framers will be able to work on scaffolding and attach temporary roof supports to the existing concrete columns, and they can do the same on the front porch.

Tuesday morning we ordered about 5 yards of concrete, and first dumped just a little bit inside the forms on the front porch. Using string lines running between the front walls on either side of the entryway, and from the front of the forms to the front wall of the house, we positioned the tubes in and put just a few inches of concrete in them to hold them in place.

We then directed JP around to the back and proceeded to pour the back patio. As usual, my role was mostly handing Doug things, but I did get in and help him pull the wet concrete into place for him to finish it. Once the patio was basically flat and he was ready to do the final finishing, JP came back up to the front and dumped the last of the wet concrete inside the form on the front porch. I then spent the next hour filling up a kitty litter bucket with wet concrete, hoisting it up on my shoulder, and pouring it inside the tubes. Fairly exhausting, but very rewarding when it was all done. When the tubes got close to being full, I stirred each one around with a fencepost and slapped on the sides of them to get all the air bubbles out. The viscosity of wet concrete is pretty amazing, especially when you have five feet of it filled up in a narrow tube.

By this time the back patio was very close to being finished, so we marked the spots for the three new columns closest to the house, and inserted three short “L” shaped pieces of rebar (about 2 feet long) for support, as well as one longer one (about 10 feet long) with a similar bend at the bottom. This steel has the tube slipped over it before the concrete is poured, and provide reinforcement to keep it from leaning either way.

Once things settled down a little bit I drove into town to get the last three 8″ cardboard tubes that will be placed up against the house. When I got back, Doug was back in the (still mostly unfilled) front porch forms, shoveling and sweating like mad. It turns out Citywide delivered a few extra yards of scrap concrete, and he was working on distributing it inside the forms. It was fairly ‘hot’ (ready to set up) so pretty tough to work with, but we brought it up level with the top of the forms sloping slightly back toward the house. The top of that concrete is still about 5 inches below the final surface of the patio, so we will next fill up with gravel, level it off, and then pour a final slab on top that will make up the finished patio surface.

I tried in vain to take some pictures, but the camera battery did not cooperate. I’ll have some more when I get back this weekend.

The only other point of interest is that we haven’t heard yet from Micah, he was tentatively scheduled to polish the floor on the main level on Tuesday (three weeks from the original pour). We’re now in the middle of a rain out courtesy Gustav, so everything will be pushed back several days at least.

If you don’t hear from me soon it is because I’ve been kidnapped by a lumberjack for threatening his livelihood…

It has been something of a slow week at our Concrete Casa while we waited for the main level floor to cure before being polished.  We arrived at the site yesterday and met briefly with the HVAC guy to strategize on the location of returns, etc. and checked out the floor in the master bedroom.

It is incredibly flat and has no visible defects after curing for just under two weeks.  The floor over the basement is much thinner (2″ vs. 5″) so is a little more prone to cracking - there are two that have appeared so far.  That is very much par for the course, they will just be filled with epoxy before polishing.  If all goes according to plan Micah and his crew will be there early next week.

I also checked out my concrete stair treads - Doug popped them out of the forms and they looked a lot better than I anticipated.  As I thought, the corners are a little rough and the shape isn’t quite perfect given the hastily constructed forms.  I don’t think they will make the cut for the stairs, but would be great to make a walkway outside somewhere.  I’m planning to build some new forms as I mentioned, I just need to get some materials and carve off a little time.  I’ve also been reading up on another technique called GFRC - Glass Fiber Reinforced Concrete - that allows for the construction of much thinner panels for concrete countertops, etc., without the need for steel reinforcement.

We are going to work on some admin tasks this weekend and perhaps start building some forms for the driveway so the next time Citywide calls with some scrap concrete we will be able to put it to use.  I spent some time last week looking into cabinets (Ikea entered the race) so we will probably mask off areas on the floor for the cabinets and kitchen island to get a sense of the flow through that area.

The only other news is I think we killed the idea of using stone on the exterior of the house.  The panels and the silver roof lean much more to the modern while the faux stone is a lot more traditional.  We are going to replace the stone around the entryway with cedal planks, similar to the look you see here courtesy of ‘hotfunk.’