With the PEX in place, Bill Brown’s team was back on the critical path. 

They had to complete placing the reinforcing steel (rebar) over the PEX and form the perimeter where the concrete ends and the hardwood floor starts.

That said, the garage is complete and we’re pouring concrete tomorrow morning!

The first few pieces of rebar are over the PEX (and the 6-6-10-10 wire mesh).

The PEX is in place and pressurized to 100 psi.

Looking toward the North wall, you can see the layout of the PEX and how the first pieces of rebar are being placed.

The garage is completed and it will be poured tomorrow.

We got it done today – the PEX is in.

PEX and the Critical Path

Since we have radiant heating (and cooling) in the house, we need to put PEX into the concrete.  Our design was different in the ground floor as compared to the lower level.

On the main floor, we had to pour at least 3 inches of concrete over the hollow core concrete panels, as it forms a composite system (the concrete and the hollow core concrete panels).  In those areas where we have hardwood floor, we will have 3 inches of concrete and 2¼ inches of hardwood flooring.  Where concrete will be the finished floor, we will have 5¼ inches of concrete.  In the lower level, we will have 3 inches of concrete where the concrete is the finished floor.

The reinforcing steel (rebar) is placed in the middle of the slab and we want the PEX close to the surface of the concrete.  Thus, on the ground floor the rebar was put down first and then we attached the PEX on top of the rebar.  In the lower level, where we have a 3 inch slab, our design is to put down 6-6-10-10 wire mesh, then attached the PEX to that.  The rebar will go on top of the PEX.

Now that the concrete was poured on the ground floor, we cleaned up the debris that fell to the lower level and had to put in the PEX.  Then, Bill Brown’s team could put in the forms and rebar.

Thus, the PEX is on the critical path.

Installing the PEX

Matt Jung sent one of his top technicians, Tom Rutledge, to install the PEX.  Bryan was his helper.

Tom arrived at the job site on time and quickly assessed the situation.  Bryan had just picked up the sheets of 6-6-10-10 wire mesh and we started. 

We laid out the wire mesh evenly over the areas where the PEX would go, cutting it to shape and securing it with nylon ties.  Then, it was time to start ‘picking rice’.  This is the term used to describe the task of laying out the PEX and then securing it to the wire mesh with nylon ties.  Just like picking rice.

It took most of the afternoon but we finished on time.  It was satisfying to see the PEX in place, ready for the rebar.

There was light rain today, which is helping the concrete to cure slowly so it won't crack (we hope!).

The PEX is done! Note the neat layout of the PEX, on 12 inch centers. Next step is to put the rebar in and place the forms around the perimeter.

After a solid day of work, Tom had a big smile knowing we met the deadline to have the PEX in place so the rebar can go in..

After pouring the main floor yesterday, it was good to have some rain today.  Water helps concrete cure slowly and reduces the risk of cracking.

Relaxing After Pouring Concrete

It was a big day yesterday as we poured our Harvest Gold colored concrete over the hollow core concrete panels.  This was a major milestone for our project.  Now, we need to pour the remaining concrete on the lower level (basement) and the garage.  The ground floor is looking great!

Our plan is to complete the next two pours before Thanksgiving.  Although the rain is good, the schedule looks tight.

Saw Cuts to Attract Cracking

Concrete cracks.  This is a fact.  We don’t want our concrete floors to crack.

There are a number of elements that we planned to reduce the risk of cracking, including the concrete mix design, avoiding sharp edges on posts in the concrete, and handling the concrete as it was poured.  However, concrete still cracks.

There are a number of techniques to control cracking and limit the cracking to specific areas.  One of these techniques is to use a saw and cut grooves in the concrete.  The purpose of these saw cuts is not to stop the cracking but to create a weak area that will attract the cracks.

It is best to cut the concrete as soon as possible after a pour, so the cracks can develop and collect in the saw cuts as the concrete cures.  Thus, Bill Brown’s team were on site today to cut the concrete that was poured yesterday.  They used string lines to follow the planned saw cuts from our design.

At this point, the concrete was too soft to cut cleanly so they left the site.

String lines showing where the saw cuts will go to attract cracking.

The concrete on the corner by the bridge looked nice today. The silver cap is where an electrical outlet will be in the floor.

After Bill Brown's team left, it started to rain. It is good for the concrete to be wet so it will cure slowly (and not crack!). Note the string lines where the saw cuts will be made.

Reed Kingston and his two sons, Cole and Graham, came to the job site to see the new concrete. They thought it would be better in the sunshine.

Jo-Anne came to our job site this morning to evaluate the colored concrete alternatives. 

On Monday, 11/16/09, we poured two samples of colored concrete – Baja Red and Harvest Gold.  Bill Brown explained that, as the concrete cures, it will lighten thus it was good for a few days to go by before evaluating the samples.

We both preferred the Harvest Gold.

(The name ‘Harvest Gold’ reminds us of the appliance colors that General Electric introduced in the late 1960s, ‘Harvest Gold’ and ‘Avacado Green.’  (We’re hoping that the Harvest Gold concrete will be more timeless than the appliances.)

Jo-Anne arrives at the job site to evaluate the colored concrete samples.

Harvest Gold with the color chart.

Baja Red ...

Jo-Anne evaluating the colored concrete - we chose the Harvest Gold.

We decided that we wanted to have an integral color in our concrete, and not have it stained after being poured.  We prefer to have a homogeneous color and not a ‘mottled’ look, which staining often yields.  The concrete will then be ground lightly into the ‘cream’ and then polished to a high grit count.

After reviewing the Grace color chart, we narrowed the choices to either Harvest Gold or Baja Red.  We were looking for a color to match with the Madrone hardwood flooring and trim, and Jo-Anne wanted to see what a ‘brick’ color would be like.

Granite Rock was very accomodating to our request and agreed to send us two trucks, each with two cubic yards of colored concrete.  We planned to pour the concrete at the front of the house over the hollow core concrete panels under the Master Suite where the concrete will be covered with hardwood flooring.  This allowed us to test the mix design of the concrete and see how it would be with the two colors.  Then, we could make a decision on the color for the larger pour that is scheduled for Thursday.

The hollow core concrete panels are soaked thoroughly with water prior to pouring the concrete. This helps the 3 inch topping bond to the hollow core concrete panels.

The first truck from Graniterock arrives with 2 yards of Baja Red. We are going to 'tailgate' the pour, since it is within reach of the truck.

It was another beautiful blue-sky California day today.  Our goal is to complete pouring concrete inside the house before Thanksgiving so that means we need to have the radiant heating/cooling PEX loops inside the concrete before each pour.

We need to pour concrete over the hollow core concrete panels in the living area and the garage on the main level, and then pour three inches of concrete in the lower level.  On the main floor, there will be 3 inches of concrete everywhere and 5.25 inches of concrete where we are having exposed concrete.  The other areas will have hardwood flooring in a 2.25 inch system (3/4 inch subfloor, 3/4 inch PEX layer, and 3/4 inch hardwood flooring).

Bill Brown was confident that his team wouldn’t be on the ‘critical path’ and that the radiant heating/cooling (PEX) would cause delays in meeting the Thanksgiving deadline.

The gauntlet was thrown …

Silicon Valley Mechanical Improves on Our Initial Radiant Design

Several month ago we started working with Ken Martin of Silicon Valley Mechanical to design the radiant heating and cooling, and the displacement air ventilation.  Ken is a Professional Engineer and has extensive experience with innovative projects, including David Kineda’s Z-squared building in San Jose, which David won a USGBC Northern California chapter award for (and was presented at the USGBC NorCal Gala on 10/30/09).

We had engaged Monterey Energy Group for the initial design of the radiant layout, which they did.  After meeting with Ken and reviewing the preliminary design with him, Ken identified a number of innovative improvements that could be made in a cost-effective manner that would allow for simultaneous radiant heating and cooling across zones as well as heating the swimming pool and cooling the wine cellar.

The highlights of Ken’s design changes included:

• Enabling radiant cooling by controlling humidity inside the house (to control the dew point and resulting condensation).
• Increasing the diameter of the PEX from 1/2 inch to 5/8 inch, which reduces the pressure drop in a loop.
• Placing the PEX on 9 inch centers (vs 12 inch).
• Using a loop layout so the average temperature differential between the supply and return PEX yields the same differential.

Placing Our First PEX Loops

Matt Jung from 88HVAC met Bryan at the project site and showed him how to take the PEX off the spool and lay out the PEX.  Matt has extensive experience with radiant heating and this will be his first radiant heating and cooling project.

We are tying the PEX to the #3 reinforcing steel (rebar), which is placed 18 inches on center each way.  Bill Brown cautioned us to ensure that no PEX loop should be able to ‘float’ upward as he will be doing saw cuts to control the cracking in the slab.  With the PEX loops pressurized to 100 PSI, Ken Martin believes that we should be OK.  Bill would have preferred to have the PEX under the rebar; for performance purposes, we will be placing the PEX on top of the rebar so it is closer to the surface (but safe from the saw cuts).

A perfect beautiful blue-sky California day to start laying out our PEX.

Before Matt arrived, Bryan used our shop vacuum to clean the debris from the perimeter voids around the hollow core concrete panels.

Matt working with Bryan to lay out our first PEX loops and zip tie the PEX securely to the rebar.