Week 6: Chapter 8- Floors

 Chapter 8

Floors 

In Chapter 8 we learned about different floor framing systems and understand the different types of floorings. We also talked about how to pick the right sustainable flooring and learned the impact of flooring selections on air quality and sustainability. 

Chapter Notes:

Framing Systems

Wood

Light frame

• Light frame construction uses multiple small wood members to carry a load. In a wall, these are called studs; when they carry a floor load, they are called joists. Most light frame floor-framing systems use 2 x 8s, 2 x 10s, or 2 x 12s. These members are spaced either 12, 16, or 24 inches on center--meaning from the center line of one to the center line of the adjacent member. Standard spans and the loads they can carry vary depending on the wood species and the grade of the lumber. Standard variations and typical spans can be found in the building code. The floor joists are then covered with a sub-flooring material--usually plywood.

Heavy Timber

• Heavy timber framing relies on a structural frame consisting of columns and beams. The horizontal beams are then used to support girders. Girders carry the weight of floor planks to the beams where the load can be transferred to the columns.

Steel

Structural Steel with Concrete in Metal Decking

• A structural steel floor-framing system relies on regularly placed columns that support steel beams. Girders span these beams and are used to carry a metal decking. Concrete is poured into the metal decking to create a floor system.

Open-web Steel Joist with Concrete in Metal Decking

• Open-web steel joists are also used to carry metal decking for a concrete-metal decking floor system.

Concrete

Concrete as a flooring system is either poured in place on site or cast at a plant and assembled on site. Cast-in-place panels will often have an additional thin slab poured in place.

Slab-poured in Place

• Poured-in-place concrete slabs are used in both residential and commercial construction. Woven wire mesh is used to reinforce the concrete, as is steel rebar. Formwork is generally constructed from wood or steel and is later removed after the slab of concrete has cured. Concrete cures through a chemical reaction that is not complete for 28 days.

Pre-cast Slabs (Single T, Double T, Plank)

• Several variations of pre-cast concrete floor slabs exist. These are poured in a factory under controlled settings and are then trucked to the job site where they are assembled.

Insulation

When a first floor is located above a crawl space, or is directly on the earth (as in a slab on grade), the underside of the floor must be insulated in most areas of the US. This insulation is used to prevent cold air moving from the ground into the finished space above, as well as to keep a stable temperature for the concrete slab. In some cases insulation may be used under upper floors--between the ceiling and the floor--for sound attenuation.

Interior Floor-Finish Materials

Multiple materials are used as floor finishes. The use of the space and building code requirements are generally used to narrow the focus on the type of floor finishes to use. Floor-finish materials are usually divided into hard surfaces and soft surfaces. Resilient flooring surfaces are a form of soft surface, in that they allow some give.

Hard Surfaces

Concrete

• Concrete is often used as a sub-floor and can easily be a finished floor surface. Various textures and colors are available, as are surface-applied finishes to seal the concrete.

Brick

• Brick pavers, although more commonly used outdoors, can also serve as a finished floor. Several patterns of brick are available. Brick pavers tend to be thinner than actual bricks, although full bricks were sometimes used to finish basement floors in historic houses.

Stone

• A variety of stones can be used as floor-finish materials. These include marble, granite, limestone, and slate. All natural stones vary in composition and color, and it is prudent to select actual materials and install them through careful selection of each piece to ensure the best results. Stone is a natural material, but it should be noted that there is a finite amount of stone and it is oftentimes available only in a remote location. Thus, from a sustainability point of view, it is important to keep the entire life-cycle costs of the material in mind. Locally available stone products are preferable to those that come from a great distance.

Terrazzo

• Terrazzo has recently regained popularity as a green building material. It is composed of a cement or resin binder with marble or glass chips, which gives it its unique coloring and appearance. The material is poured in place, and like all concrete applications, requires seams to avoid future cracking of the material. Because of its component parts, terrazzo is extremely hard and durable, and is often used in heavily trafficked areas such as lobbies.

Ceramic Tile

• Ceramic tile can be installed in two ways: on a 1 1/4-inch thick mortar bed, or as thin set where the tile is adhered to the surface below using a thin layer of adhesive. One of the most important points to consider prior to using tile is if the floor framing is appropriate. Defects in the floor framing can lead to cracking in the grout joints or the tiles themselves. Thus, the floor framing needs to have very little movement to allow for a tile-finished floor.
• Thin set Using a thin layer of wet mortar 1/4-3/8 inch, that is troweled on to create a grooved surface, tiles are then set into the mortar. The grooves allow the tile multiple points of contact with the mortar which will create a better bond. When the mortar bed has hardened, the joints between the tiles are grouted.
• Thick set (full mortar bed)-- A thicker application involves the use of a 114-inch mortar bed with reinforcing in some cases. This method is used when the substrate is uneven and must be smoothed out for proper application of the tile. Similar to a thin set, the tile must adhere to the mortar and then be grouted after the mortar bed has hardened. When tiles of different thicknesses are desired in a single flooring installation, the thick­set method will accommodate this difference to create a uniform finished surface.
• Installation-- Tile should be started in the center of the room and then installed towards the edges. The first design consideration is whether the designer prefers grout at the centerlines or a tile at the center of the room. Oftentimes this may relate to any pattern or flooring design that the designer has created. With tile work involving any pattern or diagonal layout, it is important that the designer create an accurate floor pattern drawing for the installer, accounting for actual tile size and grout joints. This will provide a map for the installer as well as assist the designer and contractor in doing proper material take-offs for ordering the tiles.

Soft Surfaces

Carpet

• Traditionally, carpet has been widely used in a variety of residential and commercial applications. Only recently has carpet come under increased scrutiny as a contributor to poor indoor air quality. Some of the issues to consider when using carpet are as follows: is there a routine maintenance plan in place to make sure the carpet is vacuumed daily and cleaned per manufacturer recommendations? Does the carpet comply with Carpet and Rug Institute (CRI) Green Label Plus guidelines? If you cannot answer yes to both of these questions, chances are that carpet is not a suitable material for the application.
• Carpet does contribute significantly to noise control, and has excellent acoustical absorption characteristics. Anti-static and anti-microbial agents can also be added to carpeting for specific application types. Recently, many manufacturers have addressed the sustainability of their products. Although some debate exists over the use of polymers in carpet, many manufacturers are working to recycle these petroleum-­based fibers infinitely within the carpet market. Reclamation programs are now being established to reclaim carpeting after it has met its useful life to divert these products from the landfill. It should be noted, however, that these programs do not exist everywhere. Prior to specifying carpet, a designer must research these issues to create a truly sustainable project.

Wood

• Wood has been used as a floor finish for thousands of years. Traditionally, wood floor finishes are strips, planks, or blocks. Several species of wood can be used for wood flooring, including oak, walnut, cherry, maple, teak, and mahogany. The most important consideration from a sustainability position is whether the product comes from a sustainably managed source such as SFC certified wood. A second issue to address is the type of finish used. Wood floors can be finished using low-VOC water-based products or wax, and do not need to include volatile organic compounds in the finish.
• Trees sequester carbon as a part of their lifecycle--removing approximately 1.5 kg of CO2 from the atmosphere, according to the ASCE (2010) Sustainability Guidelines for the Structural Engineer. The best way to reduce the carbon impact of wood is to use wood from a sustainably managed source or to reuse reclaimed wood.
• Strip- Strip flooring is the terminology used when the width of individual wood pieces is less than three inches.

• Plank- When widths wider than three inches are used, these pieces of wood are known as planks. Flooring in many historic buildings is composed of planks, in many cases random-width planks. This means that the planks vary in width from 3 inches up to as wide as 10 to 12 inches.

• Block- Individual small pieces of wood can be assembled to create a specific design. When these are assembled into squares for installation, this is known as block flooring. A common term used by some is parquet flooring, although this refers to a specific pattern.

Resilient Flooring

Resilient flooring covers a variety of materials, including all forms of vinyl flooring, rubber, and linoleum. By far, the most sustainable choices are natural rubber, cork, and linoleum. The latest research shows that while designers and architects are concerned about sustainability, 73 percent still specify sheet vinyl in healthcare environments, with 64 percent specifying VCT. According to this same study, the most sustainable choice for this environment is rubber. While the upfront costs exceed those of vinyl, the life-cycle costs are lower

Rubber

• Rubber flooring is composed of either a natural or synthetic rubber. Natural rubber is derived from the sap of the rubber plant, which is a tropical plant. It is important when selecting rubber flooring to check all of the materials from which the rubber flooring is constructed. Floorings that include PVC and plasticizers are not likely to meet sustainability criteria, nor would those that off-gas harmful toxins into the air upon installation. The adhesive used to install the rubber is as important as the materials themselves. Low-VOC adhesives should meet Green Guard Indoor Air Quality standards.
• As a material, rubber is naturally slip-resistant, but will degrade when exposed to oil. Traditionally, rubber was commonly used on stair treads and in other areas where slip­resistance was a primary concern. This type of rubber flooring comes in tile squares with raised circular pastilles.

Linoleum

• Historically, linoleum was used quite extensively prior to the availability of vinyl flooring. As such, some people may use the term linoleum to refer to all sheet flooring. In reality, linoleum consists of very specific ingredients that are environmentally safe and it is therefore, like rubber, a good resilient flooring choice for sustainable projects. These ingredients include linseed oil, rosin limestone, and jute backing. Linoleum is naturally anti-microbial and resists static build-up.

Cork

• Cork flooring has also been used since the beginning of the twentieth century. One of its earliest proponents was Frank Lloyd Wright, who used it extensively in the bathrooms and kitchens he designed. Cork was also used in many churches because of its good acoustical properties. Cork is made from the bark of the cork oak tree. It inhibits fire and has good acoustical and insulation properties. Suberin, a substance found in cork bark, is anti-microbial, mold and mildew resistant, and insect resistant.

Bamboo

• Bamboo has become a popular sustainable flooring alternative. Bamboo is a grass that can grow as much as three feet in a day. It is important to note that although bamboo is a rapidly renewable resource, one must take into account where the bamboo is coming from and how the flooring is made. Bamboo does not absorb water as easily as wood and provides a very stable flooring material. It is important to use local sources when possible to reduce to the overall carbon impact of transporting this material. Specifying air dried or kiln dried bamboo is also more sustainable.

Access Flooring

Access flooring refers to a system, not a specific material. Access flooring is a second level of flooring installed on jacks over a concrete sub-floor. The flooring system is raised on a series of jacks to allow for wires to run between the two floors. This space can also be used as a plenum for the HVAC system. Access floors are installed in 2-foot by 2- foot grids with flooring inlays. These can include carpet tiles or resilient tile squares. Access flooring allows for maximum flexibility and is often used in conjunction with open-office systems furniture.

Eliminating Flooring

• When possible and feasible, using the structural material (such as a concrete slab) as a finish material eliminates an additional material and its embodied carbon.

Interior Detailing

As mentioned previously, the most common way to deal with the joint at the floor and wall is by covering it with a baseboard to hide any imperfections.

Base Boards/Base Molding

• Baseboard trim or base moldings are made from several materials including wood, vinyl, and rubber. The most sustainable choices are FSC-certified wood trim and natural rubber trim--both of which are widely available. Stone and tile are also often used as trim in conjunction with stone or tile floors; wood is also often used with these flooring choices.
• Designers may not always want to use a base mold. Other ways of dealing with this joint are to make it a clean connection or to create a reveal.

Reveal

• A reveal joint is created when the wall surface does not meet the floor. Generally, this reveal will create a sense that the wall is floating, and this may be a desirable design detail.

Clean Joint

• A clean joint relies on careful craftsmanship to create a precise connection between the floor material and the wall material. This is extremely hard to accomplish and will result in more time and expense than the reveal joint.

Blogging assignment 

I went to the Tile Shop and talked to one of their employees. It was an interesting conversation. He talked about some of the different kinds of sustainable tiles they had. The main one they had was made of recycled glass. He also showed us some really cool hand-made tile that was beautiful. They had tile that was from places like India and China in many different stiles and colors! I even got offered a job!

Recycled glass tile:

Hand Made Tile:

Tile from around the world:

All different styles and colors: