How long does it take a slab to dry out before flooring can be installed?

This is a very important question. Moisture is a problem with fresh concrete slabs, and if you install your floor in a wet slab you will have a lot of problems in the future.

Basement Finished Superior Wall1
Concrete slab in the basement after finishing. We are now around 2 months after the installation. The concrete walls are already insulated (we used Superior Wall pre-cast foundations in this project)

Variables that affects the concrete moisture include:ambient relative humidity, concrete permeability, amount of water in the concrete when it is placed, slab thickness, presence (and thickness) of a vapor barrier in contact with the slab bottom, and method used to finish the surface.

Here you have the needs depending on the type of floor to be installed:

  1. Impermeable flooring (Vynil, for example): Internal relative humidity around 85% or surface moisture–vapor emission rates (MVER) of 3-5 pounds of moisture per square-feet over 24 hours
  2. Wood floors: 75% internal relative humidity and an MVER of 3 pounds of moisture per square-feet over 24 hours (National Wood Flooring Association recommendation)

In practical terms, just remember that to achieve the recommendations it takes time. In normal average conditions (relative humidity around 50% most of the time and temperature above 65F, concrete water-cement ratio of 50%) a 4-inch slab can take up to 3 months to dry before you can apply a floor there. But remember that this 3 month period starts only when the cement is dry.

You have some specific tests for that, that are too technical to describe here. Just to mention, the calcium-chloride test and the internal relative humidity test are tow that can be applied for this evaluation.

One of the most important features is the vapor barrier/vapor retarder. Without a vapor barrier the slab will never dry out. That’s why the construction codes put the obligation to use a 6 mils vapor barrier there. The 10mils and also the 15 mils poly sheet can better control the moisture. The best location for the vapor barrier is in direct contact with the bottom of the slab.

If insulation is used over the concrete slab a 4-month drying time should be respected before installing the EPS (normally the EPS absorbs 0.5% by volume).

To have more detailed information about that you can click here and check the Concrete Construction magazine

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3 Easy Ways to Seal Air Leaks

Good insulation is the secret for a comfy house. Remember that the winter is coming again (every year we have it), and if you suffered last year and forgot to revise your insulation remember to check these topics:

Insulate around recess lights

The majority of the recess lights have vents that open into the attic. This represents a direct route for heated or cooled air to escape. Some houses can have more than 50 fixtures like that, and some researchers already pinpointed them as the leading cause of air leaks. Lights labeled ICAT (Insulation Contact and Air Tight) are already sealed – look for the label next to the bulb. If you don’t see it, assume yours leaks. An airtight baffle is a quick, 10-second fix (normally they cost around 10-25 dollars). Remove the bulb, push the baffle up into the housing, then replace the bulb.

Progress Lighting P88-ICAT
Picture of an ICAD recess light

 

Use the Foam in Medium-Size Gaps

Once the biggest attic gaps are fixed, move on to the medium-size ones. Low-expansion polyurethane foam in a can is great for plugging openings 1/4-inch to 3 inches wide, such as those around plumbing pipes and vents. A standard 12-ounce can ($5-6) is good for 250 feet of bead about 1/2-inch thick. The plastic straw applicator seals shut within two hours of the first use, so to get the most mileage out of a can, squirt a lubricant such as WD-40 onto a pipe cleaner and stuff that into the applicator tube between uses.

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Great Stuff ® (is a well-known foam used for sealing

Caulk small gaps

Caulk is the best gap-filler for openings less than 1/4-inch wide. Silicone costs the most ($8-9 a tube depending on the brand) but works better next to nonporous materials, such as metal flashing, or where there are temperature extremes, as in attics. Acrylic latex caulk (around $2 a tube) is less messy to work with and cleans up with water.

If you have some time this weekend and would like to study a little bit more about air sealing we recommend the Department of Energy website (https://www.energy.gov/). They have great information about how to save energy and also you can learn a lot in their SAVE ENERGY, SAVE MONEY section. Enjoy.

Common spots for air leaking in a house

Insulation: controlling your house temperature and your money

Insulation is anything that blocks the movement of heat. Heat flows when molecules with more energy (more heat) bump into molecules with less energy (a colder place has a low movement of the molecules). We have a lot of ways to control this movement, and insulation is the building process that can do that. The simplest way to block heat conduction is the creation of an empty zone that has no matter. Unfortunately it is not possible to create vacuum in your walls. Because of that we have to install some material that will help our goals to block the heat exchange.

SprayFoam photo Wise Home Building
Spray foam application (Photo credit – http://www.techomebuilder.com)

The following are the most common types of materials used for insulation

  1. Batt insulation
    • Fiberglass batts and blankets
    • Rockwool Batts and Blankets
  2. Structural Insulated Panels (SIPs)
    • Polystyrene SIPs
    • Polyisocyanurate SIPs
  3. Loose-Fill Insulation
    • Loose-Fill Fiberglass
    • Loose-Fill Cellulose
  4. Spray foam
    1. Open-Cell Polyurethane Spray Foam
    2. Closed-Cell Polyurethane Spray Foam

Take a look at your electric, gas, or oil bills from past years. Thousands of dollars are wasted every single year because homes are not weatherized to today’s building standards.

Properly air sealing and insulating is the most cost-effective home improvement you can make today. Our state has has the Mass Save program, and you and your home energy specialist can determine the most economic solutions. If your house is an old one consider changing the HVAC system if you are planing a renovation. Heat Pumps are among the best in class to help you if your goal is to decrease your bills.

As you can see here, a good advice is the start. Then consider looking at the internet the educational materials available. If you have some doubts, contact us for more specific details. Have a nice weekend

 

 

Options for a house siding

If you are working on your new house the siding material is a very important decision. Also remember to check your new home location – if you have a HOA (home owner association) you can have some limitations of the siding materials to put in your home.

Siding Fiber Cement Wise Home Building
Fiber cement siding

These are the most frequent types of siding used for home building:

  1. Wood: is a pretty good option, but remember that the maintenance is high for some products. Prepare yourself to repair it in 5 – 10 years, or even before this period.People love it because of its beautiful and natural look. Commonly options are: pine, cedar, spruce, and redwood. You can either leave the wood in its natural state or paint it. You can also chose the profile for them (we will discuss it in other posts)
  2. Vinyl:  is a synthetic material that has low maintenance, is durable and has a low cost for material and also labor. Extreme weather condition sometimes can damage the material – you will find some videos and pictures in the internet about the damage of vinyl siding with heavy sun exposure.
  3. Fiber cement: usually created to mimic good quality wood sidings. It is a very reliable and durable solution. The labor cost for installation is higher, as the price of the siding itself. But you will save money for the long term because you will not have a high cost of maintenance.
  4. Engineered Wood: Unlike vinyl or fiber cement, engineered wood actual contains real wood. They also offer a great warranty time (sometimes 20 to 30 years). It requires little maintenance, and can be a good choice for your project (more expensive than vinyl though).
  5. Stucco: is a mixture of cement, lime or sand although it can be made using different recipes. The exterior is created by layering the mixture all over the house. It is not a good option for regions that have a high humidity environment. It is also very expensive to install.
  6. Brick: one of the materials that have almost no maintenance. The problem is that the labor costs for installation are extremely high.
  7. Metal: long lasting and durable, it does not rot or mold due to water damage. Some types of metal may rust if not well finished and maintained. Some people don’t like the aesthetic of metal siding, and also you can have limitations to use it because of the local HOA (if you have it already established).

Propane or Natural Gas: what is the best option for my home?

Most people don’t understand the differences between natural gas and propane when thinking about energy source for a house. We will explain here the main concepts of both products.

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Photo source: https://www.rsandrews.com

Natural Gas

Natural gas occurs deep beneath the earth’s surface, and consists mainly of methane, a compound with one carbon atom and four hydrogen atoms. Natural gas also contains small amounts of other hydrocarbon and non-hydrocarbon gases, and today is one of the most clean sources of energy. Geologists who study the structure and processes of the earth are the ones that helps companies to locate the place on earth to find the rocks that are likely to contain natural gas deposits (some areas are on land and some are offshore and deep under the ocean floor). If a site seems promising, an exploratory well is drilled and tested. Once a formation is proven to be economic for production, one or more production (or development) wells are drilled down into the formation, and natural gas flows up through the wells to the surface. In the United States and a few other countries, natural gas is produced directly from shale and other types of rock formations that contain natural gas in pores within the rock. The rock formation is fractured by forcing water, chemicals, and sand down a well. This releases the natural gas from the rock, and the natural gas flows up the well to the surface. Wells drilled to produce oil may also produce associated natural gas.

Natural gas reach your house by a complex pipeline system, with different pressurization areas – you can read more about that clicking here. It is a cheap option compared with oil and electrical sources of energy.

Propane

Propane is a three-carbon alkane with the molecular formula C3H8. It is a gas at standard temperature and pressure, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is commonly used as a fuel. Propane is one of a group of liquefied petroleum gases (LP gases). The others include butane, propylene, butadiene, butylene, isobutylene, and mixtures thereof.

To use propane as your source of energy for your house you need a tank and an agreement with a company that will provide you the gas whenever is needed (some companies also provide a rental service).

Propane vs. natural gas BTU comparison

Propane contains more than twice the energy of natural gas – one cubic foot of propane = 2,516 BTUs (British Thermal Units), while one cubic foot of natural gas = 1,030 BTUs,.

Propane is much more efficient than natural gas. Just as an example, in one hour a 100,000 BTU natural gas furnace burns around 97 cubic feet, while a propane furnace burns only 40 cubic feet.

Propane vs. natural gas cost comparison

Most of New England’s gas is piped via New York from points south and west through a limited number of pipelines. The transport system is not built up to meet consumption levels in New England. The constraints are now becoming evident, particularly in the high-use winter season. On cold days, the “spot”, or daily market price, can go through the roof: on some days over the past few winters, it was twice as high in Boston as in New York.

You have to do some math if you want to find out what is the best option for your house. If the natural gas cost is $15.00 per 1,000 cubic feet, for example, the same $15.00 will purchase around one million BTUs. This is the equivalent of slightly over 11.20 gallons of propane. If propane costs $2.50 per gallon, in this example, natural gas is the cheaper alternative.

The difference between natural gas and propane

While they are similar in many aspects, natural gas and propane also have differences. Although propane is a fossil fuel, it’s a hydrocarbon and over 95 percent of the propane used in the US is produced in North America. Like oil and coal, natural gas also is a fossil fuel. Natural gas was created millions of years ago from ancient plants and animal matter which decayed under the pressure and heat underground on planet Earth. Natural gas is known as a “clean energy alternative,” since it’s clean-burning, producing less harmful emissions than other fossil fuels (oil and coal).

Although natural gas is a greenhouse gas when released into our environment, propane is not on the same level, as it has no toxicity to harm the environment. That’s why propane may be the better choice if you value “green fuel” more than greenhouse gases. Propane also is called “liquefied petroleum gas,” or LP gas for short, like natural gas, it’s odorless so processing adds an odor so people can detect its presence.

How to calculate the energy you need

You can work together with your engineer, but you can also finds some valuable information at the internet. The residential energy calculator in this website is a very good place to check it. You can use this calculator to compare natural gas versus other fuels and discover the environmental advantages of using natural gas in your home.

Remember to check your appliances

When planing for your final home setting remember the type of energy you will choose.  Appliances can work on either natural gas or propane, but the two are not interchangeable; each fuel source requires special gas utilization fittings. If you want to switch between the two, you’ll need a conversion kit for the appliances’ manufacturer for the installation process. For electric appliances like heaters, ovens or water heaters, there isn’t a conversion process; you’ll need to replace the appliance with one specifically made for natural gas or propane.

Gas explosions: understanding the complex system behind natural gas delivery

In New England we were very worry about gas explosions that happened last week, and it is quite natural to become curious about WHY it happened. To better understand some possible source for the problem, we have to understand how the gas system works.

A house on fire
Photo Credit: theatlantic.com

The gas flowing from higher to lower pressure is the fundamental principle of the natural gas delivery systems. From the well, the natural gas goes into “gathering” lines, which are like branches on a tree, getting larger as they get closer to the central collection point. A gathering system may need one or more field compressors to move the gas to the pipeline or the processing plant.

From the gathering system, the natural gas moves into the transmission system, which is generally composed of about 272,000 miles of high-strength steel piper. These large transmission lines for natural gas can be compared to the interstate highway system for cars. They move large amounts of natural gas thousands of miles from the producing regions to local distribution companies (LDCs). The pressure of gas in each section of line typically ranges from 200 pounds to 1,500 pounds per square inch (psi), depending on the type of area in which the pipeline is operating. As a safety measure, pipelines are designed and constructed to handle much more pressure than is ever actually reached in the system. For example, pipelines in more populated areas operate at less than one-half of their design pressure level. Many major interstate pipelines are “looped” — there are two or more lines running parallel to each other in the same right of way. This is important to provides maximum capacity during periods of peak demand.

Another important part of the system are the compressor stations located approximately every 50 to 60 miles along each pipeline to boost the pressure that is lost through the friction of the natural gas moving through the steel pipe. The majority of the compressor stations are completely automated, so the equipment can be started or stopped from a pipeline’s central control room. The control room can also remotely operate shut-off valves along the transmission system. The operators of the system keep detailed operating data on each compressor station, and continuously adjust the mix of engines that are running to maximize efficiency and safety. Natural gas moves through the transmission system at up to 30 miles per hour, so it takes several days for gas from Texas to arrive at a utility receipt point in the Northeast. Along the way, there are many interconnections with other pipelines and other utility systems.

When the natural gas in a transmission pipeline reaches a local gas utility, it normally passes through a gate station. Utilities frequently have gate stations receiving gas at many different locations and from several different pipelines. Gate stations serve three purposes. First, they reduce the pressure in the line from transmission levels (200 to 1,500 pounds) to distribution levels, which range from ¼ pound to 200 pounds. Then an odorant, the distinctive sour scent associated with natural gas, is added, so that consumers can smell even small quantities of gas. Finally, the gate station measures the flow rate of the gas to determine the amount being received by the utility.

From the gate station, natural gas moves into distribution lines or “mains” that range from 2 inches to more than 24 inches in diameter. Within each distribution system, there are sections that operate at different pressures, with regulators controlling the pressure. Some regulators are remotely controlled by the utility to change pressures in parts of the system to optimize efficiency. Generally speaking, the closer natural gas gets to a customer, the smaller the pipe diameter is and the lower the pressure is. Distribution lines typically operate at less than one-fifth of their design pressure. Sophisticated computer programs are used to evaluate the delivery capacity of the network and to ensure that all customers receive adequate supplies of gas at or above the minimum pressure level required by their gas appliances. Distribution mains are interconnected in multiple grid patterns with strategically located shut-off valves. These valves minimize the need for customer disruption to service during maintenance operations and emergencies.

Natural gas runs from the main into a home or business in what’s called a service line. Typically, the natural gas utility is responsible for maintaining and operating gas pipeline and facilities up to the residential gas meter. All equipment and gas supply lines downstream of the residential meter are the responsibility of the customer. When the gas reaches a customer’s meter, it passes through another pressure regulator to reduce its pressure to under ¼ pound, if necessary. Some services lines carry gas that is already at very low pressure. This is the normal pressure for natural gas within a household piping system, and is less than the pressure created by a child blowing bubbles through a straw in a glass of milk. When a gas furnace or stove is turned on, the gas pressure is slightly higher than the air pressure, so the gas flows out of the burner and ignites in its familiar clean blue flame.

As you can see, the system is complex, and depends a lot of computers and physical connections, working at different pressure. We don’t know what causes the problem here in Massachusetts, but probably it was related with a high pressure entering a connection system within some pipe that was not prepare to absorb the pressure safely.

(Source: American Gas Association website)

Air-sealing starts at the basement

Air tightness is one of the most important area of focus in residential construction. Many builders think that achieving an air tightness number that is low enough to surpass the codes needs requires a significant increase in budget due to costly materials
and increased labor. But you can follow some simple steps that can work nicely.

This sealant is specifically designed to be applied in concrete

Air-sealing starts at the basement
The air barrier starts below ground level under the building – remember this very important concept. The code requires builders to use a 6-mil poly barrier, but you can move to a 10-mil poly, which will be applied directly over the under-slab insulation. The 10-mil thickness withstands traffic better than the code-required 6-mil and prevents
damage. During the installation all the seams are lapped and can be taped to ensure an airtight installation. When it’s available it is better to use a continuous piece of poly. If a passive radon vent needs to be installed be aware that this pipe has to go up to the roof, and this part of the job can be a leak area in the future.

Another option – but with additional costs for you – is to include some insulation in the basement floor. It can be a recycle option or common brand products that can be installed in 4″ x 8′ panels, mainly if you are planning a finish basement for some play room or office there.

Air-sealing the connection between the concrete and framing

An important area to be sealed is the connection between the concrete wall and the framing base. When it comes to sealing the sill plate to the slab you normally use the standard foam sill sealer required by code as a capillary break below the pressure-treated sill. You can also add two beads of sealant, but in our opinion is it important to add other sealants. The products are supposed to have a long service life and you have a lot of brands in the market.

Other concepts are very important also to complete your air sealing, and we will be discussing the concepts in other posts in the future