Windows have long been used in buildings for daylighting and ventilation. Many studies have even shown that health, comfort, and productivity are improved due to well-ventilated indoor environments and access to natural light. However, windows also represent a major source of unwanted heat loss, discomfort, and condensation problems. In 1990 alone, the energy used to offset unwanted heat losses and gains through windows in residential and commercial buildings cost the United States $20 billion, one-fourth of all the energy used for space heating and cooling. Continue reading
No material is “fire proof” however, proper use and assembly of fire-rated building materials can reduce a fire’s spread and extend the amount of time it takes for a home to ignite and burn. (Structural assembly is the process of layering materials when building exterior walls and roof.) Your roof is vulnerable to wildfire because it is the largest surface area of your home. The exposed, uneven surface of a roof can easily trap hot, wind-blown embers. Simple roof forms are easier to protect than complex ones due to less surface area and intersections, which may create heat traps. Use class A or B roofing materials to reduce risk. Continue reading
Conceived at a time when nature and utopian ideals were becoming increasingly prevalent in American culture and modern architecture, the Northern California community of Sea Ranch was developed in the early 1960s by architect and planner Al Boeke. Boeke envisioned a community that would preserve the area’s natural, rugged beauty and coastline, and would be based on ecological principles with minimal impact on the native environment. Continue reading
Plastering is the oldest form of decorating walls. Today, there are many types of plasters on the marketplace, with very different properties designed for different applications. Here is a quick overview of the main types of plasters:
Lime plasters are the oldest form of plasters. Their history goes back about 7,000 years predating the Romans and Egyptians. They are manufactured from lime, sand and water. Different aggregates can also be added to obtain certain desirable properties (e.g. to make it softer, harder, water repellent, able to set under water etc.). Lime has been extensively used throughout the centuries and has a very rich heritage. It is the right material for old buildings; practically it is the best choice for any building built before the 1900s.
Portland Cement Plasters
The modern alternative, developed in the second part of the 19th century at the dawn of the Industrial Revolution. By adding clay to lime and burning it at much higher temperatures results in a much harder material. Cement is unsuitable for the renovation of old buildings – the next chapter explains why.
Mainly used as interior decorative finishes on top of other plasters, being very soft they have excellent workability resulting in silky smooth finishes. On the downside: being so soft, in the presence of humidity and salts they easily break down.
Which One is Better?
If you have an old building, chances are that you have heard about the lime-cement debate, namely that “lime is good” and “cement is bad”. This is not quite true. Both lime and cement plasters have their advantages and disadvantages. Both are suitable for some applications and unsuitable for others. The point is: they are very different. Cement plasters are not recommended for the renovation of old buildings (e.g. the ones built before the 1900s); instead lime is the recommended choice. To understand why, we need to look at the fundamental differences between older and newer houses, on how they have been built.
Older vs. Newer Houses
Older houses have been designed and built to be water permeable. They got wet – no big deal – because they dry out. Being built from breathable materials, they naturally dry out. Newer houses on the other hand are built watertight using modern materials (including many plastics) designed to keep moisture out.
Mixing old and new technologies has a detrimental effect on old buildings, usually leading to their rapid decay. Here are some of the reasons why:
Hardness: new, modern building materials are harder. A new modern brick for example is expected to be stronger than a 400-year-old aged hand-made brick. Thus when old and new materials are mixed together, the older and softer materials will give way and suffer, leading to the gradual loss of the original building fabric.
Breathability: newer materials being less breathable, they do not allow for the evaporation of moisture. The accumulated moisture will again damage the weaker and older materials resulting in the decay of the historic building fabric.
Now, this doesn’t mean that you shouldn’t use any modern building material in an old building. Life is an evolution. Buildings are also constantly adapted to new uses to suit a purpose, and this often involves significant changes. However, without extensive knowledge of materials and/or building physics one can seriously damage old buildings – most of the time, unwillingly.
Lime vs. Cement – Why Lime?
Lime is the recommended choice for the repair and renovation of old buildings because lime is:
Lime is the recommended choice for the repair and renovation of old buildings because lime is:
Soft: lime mortars are softer than portland cement plasters. In fact, their hardness can be controlled during the manufacturing process. However if chosen correctly, lime must be softer than the bricks they bind together. Imagine lime mortar as an air cushion on which bricks rest. Buildings are subject to constant ground movement and vibrations. A soft cushioning can accommodate this minute movement without cracking. Over the years the soft lime will erode but it will protect the surrounding bricks, keeping the historic building fabric intact for centuries.
Cement render on the other hand is rigid. It cracks badly, letting rainwater in, resulting in increased dampness and potential frost damage. Cement mortar being harder than surrounding bricks, will erode or crack them, damaging the softer historic building fabric.
Breathable: on molecular level lime allows water vapors to evaporate freely, keeping its surface dry. Cement, on the other hand, prevents evaporation and traps humidity. Moisture under the cement plaster gradually builds up, “amplifying” dampness problems, making them worse. Cement around timber can lead to rot.
Warmer: lime having large air-filled pores, is a good thermal insulator, making it a cozy and warm material. Cement, being significantly denser with few pores, it is much colder which often leads to condensation and mold problems.
Antibacterial: lime being alkaline, it has natural antibacterial properties. It is a natural mold killer. A natural way of disinfecting cellars in the past was to paint them with lime wash.
Eco-Friendly: lime is eco-friendly and carbon-neutral. After reaching its end-of-life it can be recycled: crushed and re-used for the next lot of lime mortar. Cement is not reusable but ends up in the landfills. It also has a heavy environmental impact: the cement industry produces 10% of global man-made CO2 emissions. Heavy metals are also commonly found in cement in non-negligible concentrations.
Despite many of its advantages, lime plasters are still used a lot less than cement plasters. This happens for several reasons:
History: before the turn of the century (1900s) lime was the “golden standard” for thousands of years. Then cement has been invented. Being waterproof, fast curing, harder, capable of supporting larger loads etc. it quickly became the new “wonder material” allowing properties to be built on industrial scale: more, faster, taller – something which was not possible with lime. Thus lime has fallen out of fashion being largely “forgotten” for several decades. During this time the shortcomings of aging cement came to light – problems of durability, cracking. Poor aging etc. – and after the 1980s the building industry started returning to lime. Today lime is living its second Renaissance, becoming increasingly popular again,
Lack of knowledge / education: due to lime being largely forgotten in the 1970-80-90s, many builders and small traders just don’t know or have never been taught about lime as an alternative. So they just use cement. According to customer feedback about 70% of the tradesman / builders out there do not work with lime, so we know at times it can be challenging to find the right tradesman for your old building project.
Time considerations: lime cures slower than cement, it needs more time to dry. There is a 1-2 days wait period after each coat applied. Cement on the other hand sets within a few hours, making possible a faster turnaround between jobs. As “time is money”, many builders choose to use cement because it’s more cost effective to them; they can get more jobs done in less time.
Things are slowly changing though. More and more building owners as well as professionals are becoming aware of the real benefits of lime. Many heritage organizations and groups are making strides in popularizing lime, a key ingredient in better preserving our old buildings for the future.
As a builder or remodeler, your choice of flooring materials must satisfy your customers as well as your project budget. And if you’re fixing up a property as a rental investment, the flooring must be suitable for significant wear and tear. Some flooring choices are no-brainers: tile in bathrooms, for instance. Others are subject to the home’s style and value and to the preferences of the local market. If you’re building or prepping homes for sale, it makes sense to talk to local realtors to get a sense of what home buyers are looking for in the area. In any case, the price, quality, and style of flooring should be appropriate for the interior decor and value of the house.
Ceramic or Porcelain Tile
It’s hard to go wrong with attractive tile flooring. Tile has long been the best option for bathrooms, but home buyers also love it in everyday dining areas, kitchens, hallways, entryways, mudrooms, and laundry rooms.
In terms of color and overall style options, tile is by far the most versatile flooring material available. There’s everything from tiny mosaics to large format floor tiles to “wood look” tile that blends the look of hardwood with the durability of ceramic.
Porcelain and glazed ceramic tile are the most durable flooring options, and they require very little maintenance. Grout on floor tiles should be sealed periodically to prevent staining. This is particularly important for rental properties that you will maintain.
Tile doesn’t have to be expensive, but it is labor-intensive to install and requires a suitable subfloor and a cementboard or tile backer base. Large or tricky tile jobs are best left to a tile installer. Small and simple jobs can be done by most builders with some tile experience.
Because tile is hard and can be cold underfoot, be careful about using it in living areas, such as living rooms, bedrooms, family rooms, and formal dining rooms. However, in some markets, tile is just right for these locations. Also be careful when choosing tile for wet areas like bathrooms, entryways, and mudrooms; these must have non-slip tile for safety.
Hardwood and Bamboo
Hardwood is arguably the best looking flooring type out there and is a perennial favorite with home buyers and renters alike. Hardwood makes sense for almost any living area and, in some cases, kitchens and dining rooms. Hardwood is not a good choice for any room that frequently gets wet or sees a lot of traffic, including bathrooms, laundry rooms, and mudrooms. Bamboo flooring is similar to hardwood in performance, cost, installation, and maintenance. Today’s hardwood flooring comes both unfinished and prefinished and in solid and engineered forms. Solid hardwood is 3/4-inch-thick, tongue-and-groove planks that are usually nailed to a wood subfloor but can be glued to concrete. Unfinished solid hardwood is sanded and finished on site after the flooring is installed. Prefinished hardwood needs no site finishing. Engineered hardwood flooring is a plywood-like material with a solid-hardwood top layer. Conventional types can be nailed or glued down. There are also click-together engineered hardwood planks for “floating floor” installation.
Hardwood goes down pretty quickly and can be installed by most builders, although glue-down installation is more tricky than nail-down. Engineered floating floor installation is the easiest and fastest option. Note that solid hardwood should not be using in sub-grade basements, due to moisture concerns. Some manufacturers of engineered hardwood guarantee their flooring for basements. The main drawbacks of hardwood are cost and maintenance. All hardwood must be finished, usually with polyurethane or a similar clear-coat. The finishes offer moderate moisture-resistance and are prone to scratching and excessive wear if the floor isn’t kept clean. For these reasons, hardwood is not a good option for many rental properties.
Laminate flooring essentially is a low-cost alternative to hardwood. It’s made of wood pulp and resin and can look a lot like real wood, but discerning buyers can tell the difference. Laminate can mimic almost any hardwood style, from traditional favorites like maple and cherry to specialty types like wide-plank pine and reclaimed barn wood. Laminate flooring is made with an MDF (medium density fiberboard) core topped with a photo layer (for looks) and a thick polymer finish. Almost all types are designed for click-together floating-floor installation, which is quick and easy. Laminate can also be glued down, but this is rarely necessary or recommended. Unlike hardwood, laminate flooring cannot be refinished if the finish wears or is damaged, and laminate is impossible to repair. Its finish is tough and highly moisture- and stain-resistant, but the joints between planks are vulnerable to moisture and will swell and chip if water is allowed to sit on the floor. Overall, laminate is a great option for a hardwood look in living areas (not bathrooms) in low- to mid-price properties.
Carpet needs no introduction or explanation. It is an attractive option for many builders because it comes in so many colors and styles, it installs quickly, and it looks great when it’s new. Carpet is also warm, soft, and quiet, which is why it’s preferred by many homeowners for bedrooms and living and family rooms. Carpet’s quiet also makes it a great choice for upper-level rooms in multistory homes. Carpet should never be used in bathrooms or kitchens, where it is quickly ruined by frequent moisture, spills, and stains and is generally unsanitary. When choosing carpet for a home for sale, consider the color and style carefully. The color should be neutral and appropriate for the house, and the weave and material should be suitable for versatile use. Carpet can be a good option for rental properties because it can be professionally cleaned, but it’s also prone to permanent damage from stains and pets.
Vinyl and Linoleum
Vinyl and linoleum are different materials but are similar types of “resilient” flooring. Both come in easy-to-install tiles, planks, and sheet forms. They are highly durable and moisture-resistant and come in a wide variety of colors and styles. Vinyl and linoleum are good options for hard-working and high-traffic areas, including kitchens, dining areas, mudrooms, laundry rooms, basements, and bathrooms. The main difference between vinyl and linoleum is their materials. Vinyl is plastic, usually PVC, acrylic, and similar polymers. Linoleum is made with natural materials, primarily jute, cork, and linseed oil. Vinyl generally offers more style options and a wider price and quality range, from very low-end to premium. Linoleum comes in vibrant colors and is mid- to high-end; there are no budget versions of linoleum. Because it’s made with natural materials, linoleum can be an attractive alternative to vinyl for builders and buyers who prize environmentally friendly or natural products.
Every owner wants a cost-effective building. But what does this mean? In many respects the interpretation is influenced by an individual’s interests and objectives, and how they define “cost-effective”.
• Is it the lowest first-cost structure that meets the program?
• Is it the design with the lowest operating and maintenance costs?
• Is it the building with the longest life span?
• Is it the facility in which users are most productive?
• Is it the building that offers the greatest return on investment?
While an economically efficient project is likely to have one or more of these attributes, it is impossible to summarize cost-effectiveness by a single parameter. Determining true cost-effectiveness requires a life-cycle perspective where all costs and benefits of a given project are evaluated and compared over its economic life.
A building design is deemed to be cost-effective if it results in benefits equal to those of alternative designs and has a lower whole life cost, or total cost of ownership. For example, the HVAC system alternative that satisfies the heating and cooling requirements of a building at the minimum whole life cost, is the cost-effective HVAC system of choice. Components of the whole life cost include the initial design and construction cost, on-going operations and maintenance, parts replacement, disposal cost or salvage value, and of course the useful life of the system or building.
The federal government has numerous mandates that define program goals with the expectation that they be achieved cost-effectively.
The challenge is often how to determine the true costs and the true benefits of alternative decisions. For example, what is the economic value in electric lighting savings and productivity increases of providing daylight to workplace environments? Or, what is the value of saving historic structures? Alternately, what is the cost of a building integrated photovoltaic system (BIPV), given that it may replace a conventional roof?
The following three overarching principles associated with ensuring cost-effective construction reflect the need to accurately define costs, benefits, and basic economic assumptions.
Utilize Cost and Value Engineering Throughout the Project Life Cycle
As most projects are authorized/funded without a means of increasing budgets, it is essential that the project requirements are set by considering life-cycle costs. This will ensure that the budget supports any first-cost premium that a life-cycle cost-effective alternative may incur. Once a budget has been established, it is essential to continually test the viability of its assumptions by employing cost management throughout the design and development process. An aspect of cost management is a cost control practice called Value Engineering (VE). VE is a systematic evaluation procedure directed at analyzing the function of materials, systems, processes, and building equipment for the purpose of achieving required functions at the lowest total cost of ownership.
Use Economic Analysis to Evaluate Design Alternatives
In addition to first costs, facility investment decisions typically include projected cost impacts of, energy/utility use, operation and maintenance and future system replacements. At the beginning of each project, establish what economic tools and models will be used to evaluate these building investment parameters. The methodologies of life-cycle cost analysis (LCCA) will typically offer comparisons of total life-cycle costs based upon net present values. Other methods usually used as supplementary measures of cost-effectiveness to the LCCA include Net Savings, Savings-to-Investment Ratios, Internal Rate of Return, and Payback.
Consider Non-Monetary Benefits such as Aesthetics, Historic Preservation, Security, Safety, Resiliency, and Sustainability
Most economic models require analysts to place a dollar value on all aspects of a design to generate final results. Nevertheless it is difficult to accurately value certain non-monetary building attributes, such as formality (for example, of a federal courthouse) or energy security. The objective of a LCCA is to determine costs and benefits of design alternatives to facilitate informed decision-making. Costs can be more readily quantified than benefits because they normally have dollar amounts attached. Benefits are difficult because they often tend to have more intangibles. In some cases, these non-monetary issues are used as tiebreakers to quantitative analyses. In other instances, non-monetary issues can override quantitatively available cost comparisons, for example, renewable energy application.
These cost-effectiveness principles serve as driving objectives for cost management practices in the planning, design, construction, and operation of facilities that balance cost, scope, and quality. Analyzing the environmental costs through Life Cycle Assessment (LCA) can be complementary to the dollar cost implications of the design, materials selection, and operation of buildings. The LCA methodology, which can enhance information gleaned from an LCC, includes definition of goal and scope, an inventory assessment, life-cycle impact assessment, and interpretation-an iterative process.
The presence of drones in construction means significant changes within the industry. Drones have already begun changing the way the construction industry operates, and those changes will have continued and lasting effects. Here’s a look at some of the ways drones have already changed the industry and how these trends will impact construction operations in the future.
Unmanned Aerial Vehicles (UAVs) are rapidly replacing traditional land-surveillance methods. They are growing in popularity so rapidly that some have even abandoned the classic “bird’s-eye view” expression with “drone’s-eye view.” Drones greatly reduce the labor and time involved in producing accurate surveys. Drones eliminate much of the human error involved in the process and have the ability to capture necessary data in much less time than traditional methods would take.
Improvements to Infrastructure
Drones provide superior endurance and intelligence on job sites. Their ability to collect and report data allows them to complete work faster. The need for manual labor is all but removed from the equation. In the future, drones will take on even more integral tasks involved in large projects. They are poised to cut the time it takes to build a skyscraper by a broad margin, thereby cutting costs. Contractors who rely on drones will be able to make much more ambitious bids and complete work on time.
Communication and Management
Drone technology has evolved to the point where instant connectivity and communication on the job site are at a surplus. Drones are being used more and more as a means of maintaining constant contact at worksites. Drones that feature mounted cameras can provide video footage to facilitate communication and surveillance. They allow companies to keep tabs on employees and workers and are considered an increasingly invaluable tool for superintendents and investors. Already, communication and management are seeing a sharp increase in efficiency due to the ability to collect real-time data from drones. The decrease in delays in gathering data is having more of an impact each day. The ability to manage workflow 24/7 is unprecedented and is certain to have a significant impact on all manner of construction processes.
Improved Overall Security
The advent of drones is causing a sharp increase in security efficiency. Whether the drones are used to maintain the safety of employees or to protect the job site from theft or vandalism, they are steadily seeing greater implementation in the construction industry.
Drones have the ability to be practically everywhere at the same time. They don’t just reduce theft and keep workers safer; they create a round-the-clock real-time monitoring system that has already been adopted by a number of construction companies. They elevate onsite security and safety by a tremendous margin. Even though the FAA exacts strict standards on the use of drones, most models used by construction companies come in under the 4.4-pound weight threshold and 400-foot travel radius required to be considered “Hobby Class.” Drones that meet those criteria are not subject to stringent regulations. As of now they can be flown practically anywhere for any reason. Drones can also safely survey dangerous locations, reducing workplace accidents and increasing job site safety.
Transportation and Inspection
The use of drones in job site inspection also means a drastic increase in worksite safety by eliminating numerous dangers and safety hazards. Using drones to transport goods aerially allows companies to execute difficult inspections and keep track of everything that enters and leaves the job site. It saves money and time and keeps the site secure. Since drones are generally small with high levels of maneuverability, they are being used more and more as an alternative to traditional vehicles. Even better, drones do not have to adhere to traffic laws, which allows them to make deliveries in a fraction of the time, using half of the resources.