Our steel piling just arrived for our new project on Lake Austin. According to our geotechnical report, these pilings should average 53′ in depth before they finally come to rest on stable limestone bedrock.
Most people don’t know that Austin sits on a natural fault line (I learned that while on a geology field trip as an Architecture student at Texas A&M University), which is why one side of the river is +/- 50′ taller than the other side.
Proper engineering is critical when building on the lake.
Foundations
The Lake Austin build is progressing very nicely. Here is an update on our progress.
One of the most critical parts of any new construction project is the foundation.
A total of 83 pilings were driven for the foundation of our Lake Austin home last week. All structural parts of the house will be supported by the pilings from the front water feature to the pool.
This video is about a minute long. As you watch you’ll see the crew place the pile driver on top of the piling. A diesel-powered piston drives the piling down until it hits a solid bearing. Listen to the video, it starts off very loose and hollow sounding. When the piling reaches solid rock the sound changes to a hard solid echo of steel. This sound lets the installers know that the piling has reached the correct depth and is resting on solid ground.
Next, we’ll cut the pilings to fit inside the foundation.
Rebar is installed inside the top of the piling to connect it to the rebar in the foundation. Finally the pilings are filled with concrete.
Foundation Pour
Our Lake Austin build is progressing nicely and its foundation was recently poured. Adrian, our construction manager, was kind enough to write the following blog entry and share his photographs from the pour.
The foundation pour is one of the most exciting days on the project. It starts early, about 6 amor sooner depending on the neighborhood restrictions. Our superintendent meets the concrete truck at the job and gets him positioned in the best location.
We’ll specify where the trucks will wash out their drums after they unload. Thought should be paid to this so that trucks can be efficiently moved around the job and so that the spoils from the wash out are not driven through and are easy to dispose of after the pour. About 30 minutes after the pump truck is scheduled to start, the concrete trucks should start arriving. Spacing the concrete truck’s deliveries is a critical element of the pour. If the spacing is too short, the trucks will get backed up and concrete may start hardening in the drum before they can get it to the pump hopper.
If the spacing is too long, there will be down time between trucks, and the crew will be waiting on concrete. Spacing should be such that 1 truck is waiting so that as one empties another can move in and keep the flow of concrete smooth and consistent.
The first thing we do when the pour starts is to fill all of the interior and exterior beams. Passes are made down each beam to fill them to the top.
On the following pass, the top of the foundation is filled. The whole time the crew is moving the pump boom around, there will be a crew member following with an immersion vibrator to vibrate the concrete as it is poured. This vibrating is critical to make sure the concrete flowing into and fills the forms completely. It helps remove air pockets and allows the concrete to flow into all the nooks and crannies. Over vibrating is bad, for most concrete mixes, over-vibration creates the problem of segregation in which the denser aggregates settle to the bottom while the lighter cement paste tends to move upwards.
Estimating the volume of concrete which will be needed is a skill that is honed through experience. A volume estimate is calculated and an order placed with the concrete plant. However, after every truck has emptied it is wise to recalculate the quantity needed and fine tune the amount until the foundation is full. You do not want to be short, but you also don’t want 4 trucks waiting after you finish.
Once all of the concrete has been placed in the forms then it is time to start finishing. First a pass is made with a tamper (sometimes called a Jitterbug) to push the coarse aggregate below the concrete surface and consolidate the concrete. Most tamping is done with the finisher standing in the wet concrete, although there are roller tampers that can be used from outside the forms. Tamping should only be performed on low slump concrete. With high slump concrete, the coarse aggregates sink naturally and tamping can cause segregation of the aggregates.
A large metal or wood board is used to screed the top of the concrete. This screeding process helps compact and consolidate the concrete, and begins the smoothing and leveling of the top of the concrete. Once the surface has been screeded, the concrete is floated. This involves using a special trowel called a float. Floats can be a small hand held trowel for edges and detail work, or a large trowel called a bull float for working large areas of the concrete surface. The surface is floated to further compact the concrete, even out any depressions or high areas, and create a smooth finish on the surface. At the same time early finishing takes place, joints and edges are worked into the concrete with special hand tools.
The concrete will be left to rest until the surface begins to firm up. Once firm, steel troweling is performed to create a smooth, hard and uniform finish across the concrete surface. Steel troweling can take place by having contractors “skate” across the surface on knee boards troweling small areas at a time, or with larger trowels on poles. Then larger gas trowel machines, or whirlybirds, are used to give the top of the foundation a nice polished finish.
While the finishing is taking place, a crew member should place all of the frame anchor bolts around the perimeter of the foundation for the exterior walls to be attached to.
The form boards will be removed as the concrete starts to set. This allows the vertical planes of these areas to be finished and the holes left from the forms to be filled and finished.
After all of the finishing has been completed the slab can be left for 12-24 hours and then all of the forms can be removed. After all of the forms have been removed and the site graded and cleaned of all foundation work, frame stage can begin.
Framing the home
Our Lake Austin project is well into the framing stage and the house is really beginning to take shape. The home has come a long way since our last blog entry, which covered the foundation pour. Now that framing is well underway, the home is really taking shape and a progress update is due. This photo shows just how far this home has come since our last build along blog.
You can see that the second story framing is complete, the roof decking is in place, wall sheathing is up and windows and doors are being installed now.
Our project manager Adrian was kind enough to take a few minutes out of a busy day in the field to talk about what’s happening at the house and demonstrate some important waterproofing techniques we employ. Here’s a quick video from the field.
The next step in this build will be mechanical, plumbing, electrical and low voltage installation. We hope you’ll check back in on this build soon.
Thanks for visiting this build along. Please visit our site If you want to read more about how we design and build homes, see completed projects or get in touch with us.
Mechanical Systems
Our Lake Austin build along is really making progress since our last visit and we’ve begun installing the mechanical systems.
Because we are a Design + Build firm, we have a very close relationship with how things are built and installed. In other words, we like to make sure all project work is being carried out as our design and experience dictate they should. Today’s blog is about mechanical systems install.
Our project manager Adrian put together this walk through on how the mechanical installation phase should go.
There is an ideal sequence to installing mechanical systems
The framing is almost completed and the windows and doors have been installed. The heating, ventilation and air conditioning (HVAC) hardware is being installed along with plumbing, electrical, and other critical home systems. It’s a good idea to install the mechanical systems in order of piping priority. HVAC ducting should have the highest priority followed by plumbing and then wiring. You cannot sacrifice the efficient distribution of air conditioning because a wire was in the way when a wire can be run any number of ways without effecting it’s efficiency.
First the air handler and plenums are placed. Then the duct work is run to and from each location. Ducting should be installed with smooth sweeping curves and provide the shortest run possible to each location. There should be no pinch points or crimped duct work as these reduce efficiency and ultimately prevent the system from operating properly. Returns and supplies should be placed across the room from each other to create a good flow through the space.
After the HVAC is in, the plumbing drains and vents pipes should be installed followed by the supply lines for hot and cold water. All drain and waste plumbing should be schedule 40 PVC pipe. All of these pipes should be filled to the roof with water to test for leaks when completed. The supply lines should be pressurized then connected to the permanent water supply as soon as possible. If a water line is cut in the wall it is identified immediately.
After the HVAC and plumbing have been installed the electrical, central vacuum, and low voltage should go in. Prior to any wiring being run, we like to set all of the electrical boxes and then walk through the house with the client and discuss all of the locations. It gives us a final opportunity to make changes and confirm locations prior to running wire. Moving a blue box is easy compared to rewiring later. Electrical and low voltage lines should not run together or closely parallel. This creates interference in the low voltage lines and should be avoided.
Modifications will be needed along the way during mechanical installation. The framer will need to modify some areas to allow the plumbing or HVAC to be run as they should. All modifications must maintain the structural integrity of the structure.
We will be installing these systems over the next couple of weeks. Next time we’ll look at stucco, which will be starting soon.
Inspections
Our Lake Austin Build Along is ready for the City of Austin to perform inspections. The City will inspect the home to certify it meets all required codes. All plumbing, electrical and other mechanical systems will be covered with drywall soon after the inspections are passed and completed.
Pre-inspection Inspection
When the city inspects our build, they’ll check for code compliance. Their inspection will not ensure that we are building to plan. It’s our job to ensure all of our plumbing, electrical, life safety, low voltage and other mechanical items have been placed properly. When an electrical box is in the wrong place or a plumbing supply is out of line, it can cause a lot of problems down the line. We monitor our work to avoid going back into the walls after drywall installation to make costly, time consuming repairs.
Do it right, do it once
Adrian, our project manager, made this short video about our pre-inspection examinations. He explains why our superintendents are careful to follow the plans. Several sets of trained eyes regularly inspect our builds. As
Foam Insulation
Our Lake Austin build passed its city inspection this week and had open cell foam insulation blown in yesterday. Stone masons were busy working on the home all week and a large group of workmen were on site. By the time the Best Insulation crew had their trailer set up on site, the home was a beehive of activity. Because all windows were covered with plastic sheeting, the house got hot quickly.
What is Open Cell Foam
The type of spray Polyurethane foam (SPF) used in the build distinctly impacts project costs, application methods, and building performance. When foam is installed in a home a cellular plastic is being made on site. For simplicity, think of it as bubbles in a bubble bath. The insulation cures very quickly and of course is dry once cured, unlike the bubbles in a bubble bath.
Open vs. Closed Cell Structure
Open-cell foam consists of tiny bubbles or cells that aren’t fully encapsulated; they are broken, torn or ripped. Because they’re broken, air fills the open space inside the bubble, which results in a soft, spongy material.
Closed-cell foam differs in that every bubble or cell that makes up the foam is completely encapsulated and packed tightly together. The bubbles aren’t filled with air, but rather a gas that aids foam expansion and insulation properties. This results in an altogether harder material than open-cell foam.
The blowing agent, which aids in forming the bubbles or cells that make up foam structure, is usually water for open-cell and high-R-value chemicals for closed-cell. Closed-cell foam is roughly four times as dense as open-cell for insulation applications.
Why Open Cell Foam?
Open cell foam insulation is a high performance building material that offers advantages over traditional fiberglass insulation.
Here are a few advantages:
- Reduced labor and waste
- Sound proofing qualities
- Easy application over curved and irregular surfaces
- Resistance to water damage
- All-in-one insulator and air barrier
- Improved indoor air quality
- Savings on heating and cooling cost
The Install
We sprayed a two-component open cell foam in the lake house. First, two chemical ingredients were mixed together on-site using special trailer mounted equipment. Then, heated hoses conveyed the components to a mixing gun that sprayed the chemicals on the surfaces to be insulated. A chemical reaction began as soon as the chemicals were mixed. The liquid spray mixture foamed, expanded, and eventually hardened to fill all the void spaces.
Adrian, our project manager, cut this video of spray day. Notice the installers wearing Tyvek™ suits and respirators for protection from chemicals and noxious fumes.
Drywall Install
Our Lake Austin build passed its insulation inspection and drywall board has been fastened to the frame of the house. Let’s take a look at the current state of the walls and see what is next for our project.
What is Drywall anyway?
Drywall, (also known as Sheetrock, Wallboard, Plasterboard or Gyp Board) is a panel made of Gypsum Plaster pressed between two sheets of thick paper. It is mostly used as part of interior walls and ceiling construction. Gypsum board’s noncombustible core gives it a passive fire protection advantage over plywood, hardboard, and fiberboard.
Natural Gypsum occurs in sedimentary rock formations, and is found in over 85 countries. The United States, Canada and Mexico have some of the largest reserves of high-quality gypsum. Gypsum is a non-toxic mineral mined in 17 states. Iowa, Texas, Utah, and New Mexico are particularly important producers.
Large Gypsum Crystal Formation Underground
While most gypsum produced in North America is used to manufacture sheetrock panels or building plasters, it can also be used as a soil additive, a primary ingredient in toothpaste and medical casts.
Did you know? Gypsum has been used in construction since the days of ancient Egypt, where it was used in building the Pyramids. Some of this construction is still visible over 5,000 years later.
Today, Gypsum Board is used in over 97% of all new homes constructed and our Lake Austin build is no exception.
State of the build
Our Project Manager Adrian took a few moments to make this video to fill us in on the homes progress and talk about the process of installing drywall.
Cabinets and Trim
Cabinets and trim! Our Lake Austin build is proceeding on schedule. The extra effort our superintendent spent making sure mechanical systems were installed correctly and according to plan is paying of nowf.
The most important aspect of cabinet installation is performed long before cabinets are brought into the house. Precise, careful measurements should be taken by the custom cabinet manufacturer after the mechanical systems are installed during framing. These measurements of the home will provide a road map to the cabinet builders back at their shop.
Since the topic of cabinetry has been breached, let’s talk a bit about them and why ours are built custom.
About Custom Cabinets
Cabinets are boxes with shelves, doors and drawers. They are also furniture for your kitchen and a focal point of your home. They should be built to last and express the personality of their owner. Cabinets from a big box store are cheaper, but they are never a better value than those that are custom made.
Built to last
Custom cabinets come from the hands of skilled craftsman – not from assembly lines. Our cabinet makers take pride in their work and use quality materials to ensure that their finished product is a work of art. Quality cabinets are durable and built to last.
Built to fit
Stock cabinetry is built for stock kitchen and bathroom sizes. If you have an unusual space, fillers will be used to cover the extra space. When you install custom cabinetry, almost every inch of space will be usable.
Built for you
Custom cabinets provide you with a personal, customized selection of wood, style, finish, and hardware options. Stock cabinetry is made on an assembly line in batches at different times and often results in non-matching materials and finishes. Custom cabinetry is made per order with hand selected woods and is all finished at the same time.
This build has quite a few special lighting features that had to be accounted for during cabinet design and installation. That is part of the reason our superintendent had to pay close attention to the details of this install.
Despite a wet, rainy week we were able to find a break in the weather to film a short video.
Life Safety Systems
Mechanical installations are nearly finished at our Lake Austin build and life safety systems are the focus of this weeks blog.
A life safety system is a part of any building’s infrastructure that monitors the environment for changes in state that indicate the presence of fire or smoke. It then reacts to this change of state in a manner that reduces or eliminates the risk of injury or damage.
Why Install Sprinklers?
The decision to install fire sprinklers at our Lake Austin build was made during design. Our client’s home is located in an area with no fire hydrants because its water is sourced directly from Lake Austin.
The fire sprinklers we’ve installed in the Lake Austin home are primarily designed to help save lives in the case of a fire. They can slow the spread of a fire and allow the occupants to escape the home.
They are not pure fire extinguishers that can be relied on as the sole protective measure in a home, but they are an important part of a well designed and robust life safety system.
Fire sprinklers are a reliable and simple way to protect your home and family from fire danger.
The movies have shown us that triggering one sprinkler will set off the whole system. This is not true. Only the sprinkler heads that are exposed to extreme heat from a fire will release water. 90% of home fires are stopped by a single sprinkler.
Hidden in plain sight
The orange sprinkler piping is visible throughout every room of the home now. The temporary blue caps cover all the sprinkler heads to protect them from damage until the drywall and wood will conceal them from sight.
These heads act as a plug to hold the water back until extreme heat triggers their activation.
Sprinkler Fact
Smoke will not trigger your fire sprinklers.
Don’t worry about a sprinkler system affecting your homes finished looks, the sprinkler heads will be fitted with a different cover plate as the home is finished. This cap will be painted or textured to match the walls they are concealed behind. Cover plates can be made to match any finish or paint color.
Sprinkler Fact
If one sprinkler head is activated, the whole system is not automatically triggered. \
The sprinkler system is meant to function even if electricity service is lost in the home. A tank can be installed to holds a reserve supply of water for the sprinkler system.
Here you can see the master valve assembly for the sprinkler system.
Here is a short video that explains exactly how our sprinkler system should work. If you’d like to talk about building in Austin, please visit our site. We’d love to talk.
Thanks for following our Lake Austin build. If you have an idea for a home project, we’d love to hear about it.
