Silt Fences

Before I had any experience working in the field, I thought silt fences were just to keep top soil and other types of soil and aggregate from leaving the perimeter of the site. One day on the job site I asked the superintendent what exactly a silt fence was used for and he explained that silt fences weren't for containing soil on the site, but that was a side effect. Silt fences are predominantly used for protecting streams and other bodies of water. The synthetic liner(in black pictured above) guards from loose soil leaving the area during a heavy rain that could ultimately end up in the lake or stream.

To install a silt fence on the site, you want to keep the synthetic on the inside of the property, and the stakes on the outside, just as you can see in the photo above. Old school ways of putting up a silt fence involves first putting in your stakes. These are mostly wooden, but could be some type of composite metal. After the stake are set in the ground, you trench out an area of earth so that the silt fence can rest above and below the grade of the land. Then the liner is attached to the stakes. Once the liner is attached to the stakes, the excavated dirt can be filled back in and your silt fence is installed.

When I was looking up different methods of installing silt fences, I ran across the website. Burchland Manufacturing has created a plow like piece of equipment that speeds up the process of installing the material. The piece of equipment attaches to the front of a bobcat where it then plows and lays out the silt fence in one motion. The synthetic roll is attached on a peg and is rolled out into the trench after the plow on the machine tills up the area. The pictures below taken from their website where you can find more information regarding the the installation process and information about the equipment. http://www.burchlandmfg.com/silt_fence_installer.php .

House Wrap

What is the purpose of house wrap? House wrap is a protective synthetic membrane used to protect the outside of your home from moisture. It is just one more protective measure to ensure your home lasts for a long length of time. House wrap helps to prevent moisture from getting into the framing of a home and rotting out your sheathing and potentially the studs. It also helps to protect against mold and other related problems.

House wrap, if installed properly, can second as an air barrier. Either heat or cool air from the home will be sealed in and less likely to escape through your home since the house wrap is sealed against the building envelope.

House wrap was developed as an alternative to a tar based sealant for protecting the house. The synthetic material is much easier to apply and it goes up faster since it is lighter than applying tar. It is applied over the sheathing but behind the siding of the house.

A few key points that FEMA an the NAHB made were:

- house wrap is not supposed to be used as a vapor retarder. The purpose of house wrap is to let air pass through

-depending on the climate in which one lives, use a house wrap or building paper. Although they are similar, each one works well in their respective climates. The chart below taken from FEMA's website, explains in further detail when to use house wrap as opposed to building paper

-if the house wrap isn't installed correctly, then it could do more harm to your home and good. Water could become trapped and then potential mold growth or rotting could occur.

Trusses

The particular truss pictured above is a pre-manufactured truss used for a room. Trusses come in all shapes and uses if you decide to use prefab trusses as opposed to stick built. Conventional stick built trusses work just as well, it just depends on what type of roofing style you are going to use. Typically stick built trusses are most all of the time used when roof angles and pitches are not conventional, such as on a custom built home. That being said, these trusses can be used on regular pitched roofs as well, it just takes longer to build and set the trusses.

It also comes down to a money issue. Trusses that are prefab can be put up and set quicker, thus saving time. In the building business, TIME = MONEY. I would propose to use prefab trusses whenever possible because they help to save time. I haven't done a study on how much expensive trusses are than conventional stick built roof trusses, and it may come to a wash. Even so, if you can put up 2 more homes a year, or one more commercial project a year because of the time savings, you have already made more money. So from a monetary standpoint, it seems like a win/win situation. With the numbers I proposed, I was being quite conservative, so if the time savings are even more, then you have really done your business a favor.

There are all sorts of trusses available. There are trusses for putting air handlers in the attic, gable trusses, scissor - used for a vaulted ceiling, vaulted, shed, and the list continues on and on. Below is a picture, taken from http://www.raftertales.com/home-remodeling/roof-truss/, showing the many different options available with prefab trusses.

Also, below is another photo of a scissor truss in a set of plans we received over the summer for a home built in Roanoke. The scissor truss is in the family room. As you can tell, it creates a nice vaulted ceiling.

Soffit

The purpose of soffit is to reduce moisture in the attic and to also help to stabilize the temperature in the attic year round. Soffit is a plastic material with small holes that covers the outside extension of a roof, the eave. This allows moisture to dry through air flowing up the into the attic and out through the ridge vent. This photo is taken from class lectures.

It is important to regulate your attic temperatures throughout the year to extend the life of your roof. If you notice the gap between the wall section and the eave there is a gap. This is for the air to flow from the outside up into the attic. This is used to heat and cool the attic with the outside air. An attic acts as an oven in the summer times when attic temperatures reach more than 100+ in the summer months. Not only are your shingles being baked from the hot summer sun on the exterior, but the heat from the attic bakes the shingles from the inside as well. This causes the shingles on your home to wear faster than expected.

Flashing

Flashing helps to mitigate water from coming into the wall cavity. It acts as a barrier where moisture drains from. This particular area look as if there will be a break within different types of cladding. You can see where the brick ladder reinforcement is just above the flashing. The flashing will keep water from penetrating the break between the exterior cladding.

In class we learned about two different types of flashing. L and Z flashing. L flashing extrudes from the opening close to a 45 degree angle. Although this flashing doesn't have a 45 degree angle, it doesn't come straight down from the block on the wall. Z flashing comes out from the opening at a 90 degree angle. An example of Z flashing is below.

Another thing to take into consideration when dealing with wall cavities and flashing is that moisture has to have someway of escaping. In order for water to exit the wall cavity, weep holes are usually drilled at the bottom of wherever the cavity ends. Weep holes are pieces of small string that are bunched together. The soak up any moisture in the wall cavity and allow it to exit the building. The photo below shows an example of a weep hole.

Concrete Slab and Camber

After the concrete pour, this will be the stage of the elementary school at Prices fork. The steel reinforcement helps to strengthen the concrete. You can see the hangar bars that run horizontal on the left hand side where the rebar circles around. These bars are used to provide support for the rebar to "hang" on.

The way that the rebar is oriented on the left hand side is called an open loop system since the rebar does not make a full enclosed circle around the hangar rebar. If you notice, the rebar is held together at the cross sections with small pieces of rebar ties. These are similar to a twistie-tie you would find at the grocery store, but much more heavy duty. The rebar ties make sure the rebar doesn't move when the concrete is being poured.

The yellow material that you see on the top right hand of the photo is a vapor barrier. Vapor Barrier is a plastic lining used to keep moisture from entering the building envelope. Although this doesn't always stop moisture 100%, it does a good enough job to keep ENOUGH moisture out so that it won't effect the building. Although, if the vapor barrier is torn or defective before the pour, the material won't perform like it should, and chances of moisture entering the envelope are much higher.

One aspect that is not shown in this photo(because it is not a large enough area or supports enough weight) are cables, or tendons, in the concrete. These are more prevalent in parking garages where there is a lot of dead weight, but also high amounts of live load. These tendons can be stretched to create camber. Camber is the pulling of cables in the concrete so that the concrete "bows" slightly upwards once poured. When extra live load is added to the concrete with camber, it then settles to level as opposed to being level to start with and then being concave. The structural engineer will inform the contractor if there needs to be camber within in your concrete.

Once the concrete has been finished, the formwork(plywood material surrounding the stage area) will be removed and the concrete will be ready to go.