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Reducing Holdowns Using OSB Exterior Sheathing

Jim Houlette — Sat, 31 Dec 2011 21:20:56 +0000

Tired of all the holdown straps?

You can eliminate many of the metal holdown straps from the upper floor wall to the main floor wall by modifying your OSB wall sheathing layout. When the OSB wall sheathing is continuous over the floor framing section or lapped with the rim board uplift loads can be transferred.

If you are utilizing prefabricated wall panels you can still have the OSB extend to the middle of the rim board. Just have the OSB extend below/above the plates as build in the shop. The only caution is, extra care is needed to prevent the overhanging OSB sheathing from being damaged during shipping.

This concept can also be utilized at the foundation sill plate to help reduce uplift loads that would otherwise require embedded straps such as STHD10RJs. In that situation, cross grain bending is not desired on the sill plate as the load transfers to the anchor bolts. The cross grain bending can be removed from the equation using mud sill anchors (MAS) attached to the exterior face of the OSB sheathing in lieu of anchor bolts. A great solution when utilizing prefabricated walls.

Typically, when building with wood you want many smaller fasteners that distribute the load out evenly rather than a few large fasteners concentrating the load.

EVstudio | Architecture and Engineering | Denver and Evergreen

Originally posted 2009-07-31 00:01:56.

Repairs to Concrete Foundations Made Simple Using Carbon-Fiber Kevlar Grid Straps

Jim Houlette — Sat, 31 Dec 2011 21:20:52 +0000

From Fortress Stabilization Systems

EVstudio recently met with Pinnacle Construction where they introduced us to Carbon-Fiber and Kevlar Grids used to repair foundation walls. Carbon-fiber has recently been introduced into the construction industry due to its very high tensile strength, lightweight and workability. Sections of the grid can be adhered to the concrete surface using a high strength epoxy bonding agent.

Fortress Stabilization Systems appears to be the leader in introducing this new technology to the construction industry, applying it to many different situations from bridges to basements. The most useful application for residential would be the Carbon Staples, Kevlar Neckties, and various shapes of Carbon-Fiber/Kevlar grids used to control cracks and provide additional strength to an otherwise failing foundation wall.

EVstudio's structural department is very excited to research more about Carbon-fiber and other applications it can be used in. Carbon-fiber is a great alternative to commonly used steel repairs.

From Fortress Stabilization Systems

Originally posted 2010-03-02 00:01:01.

ALTA Table A Optional Survey Responsibilities and Specifications

Sean O'Hara — Sat, 31 Dec 2011 21:20:47 +0000

ALTA surveys are a cafeteria style survey where the client can pick specific items to build a survey that meets their specific needs. In addition to the standard survey requirements for all ALTAs there is the list of options on Table A which include:

Monuments placed (or a reference monument or witness to the corner) at all major corners of the boundary of the property, unless already marked or referenced by an existing monument or witness to the corner.
Vicinity map showing the property surveyed in reference to nearby highway(s) or major street intersection(s).
Flood zone designation (with proper annotation based on federal Flood Insurance Rate Maps or the state or local equivalent, by scaled map location and graphic plotting only.)
Gross land area (and other areas if specified by the client).
Contours and the datum of the elevations.
List setback, height, and floor space area restrictions disclosed by applicable zoning or building codes. The source of such information must be disclosed.
Exterior dimensions of all buildings at ground level
Square footage of exterior footprint of all buildings at ground level, gross floor area of all buildings; or other areas to be defined by the client
Measured height of all buildings above grade at a defined location. If no defined location is provided, the point of measurement shall be shown.
Substantial, visible improvements (in addition to buildings) such as billboards, signs, parking structures, swimming pools, etc.
Parking areas and, if striped, the striping and the type (e.g. handicapped, motorcycle, regular, etc.) and number of parking spaces.
Indication of access to a public way on land such as curb cuts and driveways, and to and from waters adjoining the surveyed tract, such as boat slips, launches, piers and docks.
Location of utilities (representative examples of which are shown below) existing on or serving the surveyed property as determined by either observed evidence or observed evidence together with evidence from plans obtained from utility companies or provided by client, and markings by utility companies and other appropriate sources (with reference as to the source of information). This includes railroad tracks and sidings; manholes, catch basins, valve vaults or other surface indications of subterranean uses; wires and cables (including their function, if readily identifiable) crossing the surveyed premises, all poles on or within ten feet of the surveyed premises, and the dimensions of all
crossmembers or overhangs affecting the surveyed premises; and utility company installations on the surveyed premises.
Governmental Agency survey-related requirements as specified by the client.
Names of adjoining owners of platted lands.
The distance to the nearest intersecting street as designated by the client.
Rectified orthophotography, photogrammetric mapping, laser scanning and other similar products, tools or technologies may be utilized as the basis for the location of certain features (excluding boundaries) where ground measurements are not otherwise necessary to locate those features to an appropriate and acceptable accuracy relative to a nearby boundary. The surveyor shall (a) discuss the ramifications of such methodologies (e.g. the potential accuracy and completeness of the data gathered thereby) with the title company, lender and client prior to the performance of the survey and, (b) place a note on the face of the survey explaining the source, date, relative accuracy and other relevant qualifications of any such data.
Observable evidence of earth moving work, building construction or building additions within recent months.
Any changes in street right of way lines either completed or proposed, and available from the controlling jurisdiction. Observable evidence of recent street or sidewalk construction or repairs.
Observable evidence of site use as a solid waste dump, sump or sanitary landfill.

Originally posted 2010-01-25 00:38:09.

Surveys and site layouts

Understanding R-Value and Insulation

evstudio — Sat, 31 Dec 2011 21:20:42 +0000

This post is provided by Earthcore SIPs.

There are many conditions that determine the effectiveness of any building material to provide comfort and energy efficient performance. R-Value is only one of these factors or measurement tools.

R-Value is the measure of resistance to heat flow through the defined material. The higher the R-Value the less heat will transfer through the wall, making the system more energy efficient.

R-Value is determined by testing or by the addition of tested components. When “effective” R-value is used, it represents that at a given condition or circumstance, the system performs the same as a product with the “real” R-value.

It is important to understand the conditions at which the “effective” R-value was determined, and see if your application is the same. For example, a masonry wall may have a high “effective” R-value for a 5 hour test period, but have a very low R-value during a 24 hour test period. Where “real” R-value products will have the same R-value during both test periods.

There are several items to consider when evaluating R-Value and it’s effect on your project

Effective R-Value

An example would be masonry products. Masonry product have a very low R-Value but have a high thermal mass. Foam type products have a high R-value but low thermal mass. There is not a standard measurement or number for the energy effectiveness of thermal mass. While R-value resists the flow of heat, thermal mass delays the transfer of heat but does not reduce it. During a short period, thermal mass has the same “effective” R-value, so it is sometimes advertised with this R-value rating. It is not a real R-value but, under those conditions, an “effective” R-value. Please review other technical bulletins for more details and other related items.

Installed R-Value vs Advertised R-Value

It should be noted that R-Value of an item is the value that was tested in a laboratory and is real, but the item may not perform at the same R-value when installed. Most insulating materials obtain their insulating values from trapped air spaces, often the higher the density of air pockets, the higher the R-value. If these air spaces are compressed, a lower R-value will result. For example, batt type insulation may be rated at R-19 in its free state, but requires a 6 ½” thickness to obtain that value. When this material is installed in a 5 ½” frame cavity, the batt is compressed and the R-value is less than R-19. Likewise, putting two batts in the space for one does not increase insulating value; it might even reduce the R-value. Review the Technical Bulletin on Air Infiltration in Insulation for more related information.

Nonuniform Material

Whole wall R-value is the term used to describe the average R-value for the total wall taking into consideration variations and non-uniformity’s in the insulating material. Often, the R-value of the insulating material is advertised without stating the effect of the total system.

An example would be installing an R-19 batt insulation in a 2×6 frame wall. The resultant “whole wall R-value” is the average of the R-19 insulation and the R-5 stud. Tests have shown that the actual “whole wall R-value” of an R-19 wall system to be R-13.7, much less than the R-19 advertised. This applies to all non uniform wall systems.

The R-value of building materials may be effected or altered by the following items.

Non uniform material
Thermal shorts
Material compression
Air infiltration in the insulation
Humidity
Temperature swing or range of environment
Effects of time and aging.

Along with R-Value, several other factors need to be considered to determine the overall energy efficiency of a building structure.

Thermal Mass
Air infiltration in the building
Radiated heat gains
Internal heat gains
Latent and Sensible heat transfer

Originally posted 2010-03-05 00:01:00.

LEED Project Team Formation is an Important First Step in any LEED Certification Project

Elicia Ratajczyk — Sat, 31 Dec 2011 21:20:37 +0000

The first step in preparing for the LEED Certification process on a building project is the formation of the LEED Project Team. Integrated design is one of the most important sustainability strategies and a good project team will become the key to an integrated, efficient, cost-effective and ultimately successful sustainable design and LEED Certification project. It is important to include as many of the Project Team members as may be needed early in the process because this allows for a more seamless flow of information and work and allows for the valuable input of multiple experienced and knowledgeable stakeholders in the project from the onset. Every project will have a different team formation because every project will have different needs and sometimes multiple roles may be filled by a single team member. The following list includes some of the most common team members that may be included on a LEED project:

Project Administrator – By default, the person who registers the project with the USGBC will become the Project Administrator for LEED Online. This person should be a LEED-AP (accredited professional), if possible, and should be experienced and knowledgeable about LEED certification projects and process. This person is responsible for managing the assignment of team roles in LEED Online and the management of all of the LEED documentation and coordination throughout the LEED certification process.
Developer / Owner – This is the person responsible for making the final decisions for the project including all strategies, targets, project goals, financial decisions etc.
General Contractor – This is the person responsible for the construction of the project and plays a key role in assuring that all of the LEED strategies and design elements are effectively and efficiently carried through to reality. It is helpful if this person has previous experience with LEED or green building projects but not essential if they are included in the process from the beginning of the project and there is a LEED-AP or experienced Project Administrator on the project team.
Sustainability Consultant – This person is knowledgeable and experienced with LEED, green building or sustainability projects. This person should be a LEED-AP as well and will provide valuable knowledge, resources and structure to the LEED certification process.
Architect / Designer – This is the person responsible for the architectural design of the building. An architect with experience in LEED or other green building or sustainability projects can skillfully include highly effective, low-cost sustainability strategies into the design of a high performance building such as passive solar design, reduced building footprint, etc.
Landscape Architect – This is the person responsible for the landscape planning of the site and can also skillfully include a number of highly effective, low-cost strategies into the design that will benefit the project goals and LEED certification.
Engineers – This category may include Civil Engineering, Structural Engineering and MEP (Mechanical, Electrical & Plumbing) Engineering. The engineers are responsible for a large portion of the LEED criteria, including both pre-requisites and credits and are the key to designing a truly integrated and efficient building design.
Energy Modeler – This team member will model the energy usage of the building according to the required standards and utilizing the required software platforms that conform to LEED criteria and a myriad of additional modeling needs that may be included in the project goals such as analysis for tax incentives, energy rebates and additional building or energy certifications for the project.
Commissioning Authority – This is the person responsible for organizing, coordinating & overseeing the Commissioning of the building after construction and according to the LEED criteria, must have previous experience on a minimum of two LEED projects. Although the commissioning does not take place until after the major building systems have been installed and are operational, it is very helpful to include this team member early in the process so that they can provide valuable information, resources, real-world experience and knowledge from their previous LEED projects.

These team members are essential to the success of a LEED certification and building process and each of the above mentioned roles should be filled in some capacity. As previously mentioned, it is possible that a single team member may fulfill several of the above mentioned roles. For example, it is common for the MEP Engineer to also be the Energy Modeler and even sometimes the Commissioning Authority or for the Architect or Designer to be the Project Administrator and/or Sustainability Consultant. The following list includes some more team roles that are helpful to a LEED certification project and should be included in the Project Team meetings whenever possible:

Broker / Real Estate Agent
Marketing / PR Director
Financial Manager / Cost Consultant
Facility Manager
Suppliers
Key Sub-contractors
Key Stakeholders (building tenants, users, community members)

EVstudio includes several LEED-AP’s who are experienced on previous LEED certification projects. In addition, EVstudio incorporates green building practices and sustainability strategies into our design strategies for each project. There are many strategies that improve livability without increasing cost. It is our philosophy that sustainable design is sensible design and that many of the most effective strategies require great designers, not great amounts of money.

Originally posted 2009-09-12 00:24:19.

Raft Slab-on-Grade Foundation

Jim Houlette — Sat, 31 Dec 2011 21:20:36 +0000

A Raft Slab-on-Grade foundation can be as simple as a 4” thick slab with no reinforcement and a shallow perimeter rib to an 8” thick slab heavily reinforced with deep ribs spaced roughly 10’o.c. The wide range of concrete thicknesses and reinforcement is a function of many things such as soil type, loads, exterior finishes, allowable deflections, climate, and many more factors. The primarily factor that influences the slab thickness, reinforcement and rib sizes of a slab-on-grade foundation is the soil type.

If the soil is a sandy material with non-swelling fines to allow good compaction then the slab-on-grade foundation will be evenly supported, and has a low risk of soil movement. This raft foundation will just need the minimum slab, ribs and reinforcement.

If the soil has swelling material that is susceptible to changes in moisture content then the raft must be designed to resist this movement. The use of reinforced ribs is an economical way to strengthen the slab. Ribs are below the slab and are spaced evenly to create a grid or waffle appearance. This is done in lieu of thickening the entire slab because you gain more strength with depth and will typically use less concrete and steel reinforcement to achieve the same design capacities.

Raft foundations have been used for residential structures, commercial structures and heavy construction structures. The reason for the wide range of uses is simply because the raft slab-on-grade foundation is simple to construct and one of the most cost effective foundations. Typically, little earthwork is needed, sites are leveled, ribs are trenched, reinforcement placed and then concrete is placed. Also, since the raft foundation is just reinforced concrete, access to plumbing can be achieved by removing sections of the slab and then patching as needed. If the slab is post tensioned then accessing the plumbing is much more difficult.

But the raft foundation has its problems as well. On sites with high risk of soil movement the slab can become expensive if deep ribs and heavy reinforcement is needed. That is when a post tensioned slab may become cost effective. In addition, the control of visible cracks in the slab can be difficult. Concrete shrinks as it cures and if control joints are not placed appropriately or sufficient reinforcement is not used the owners may be upset with visible cracks. Cracks caused by shrinkage do not indicate failure, but can be an eye sore and a difficult conversation with the owner.

PROS
Cost effective
Common Construction
Low Tech
Sections may be removed to Access Plumbing

CONS
Limited Design Capacity
Does not respond well to Soil Movement

Learn more about different foundation types.

Originally posted 2009-11-03 10:42:22.

Wind or Fallen Tree Damage Report by a Structural Engineer

Jim Houlette — Sat, 31 Dec 2011 21:20:34 +0000

From 9News

Unfortunately, we are experiencing some high winds as the year ends. Although structures built in the last 20 years should have been designed to withstand a 90mph wind gust or higher in some areas along the front range it doesn't protect the structures from falling trees or other forms of wind damage. There are of course many structures built prior to the building codes that may not be able to withstand the high winds.

If your structure is damaged from these high winds or anything else (fire, snow, water, soil movement) you may need a structural engineer to inspect the structure to determine if it's safe and what repairs are needed.

EVstudio can help you get through this. Our structural engineers are based in Denver and Evergreen and live throughout the Denver area.

In an emergency please call or email Jim Houlette, PE at 720-975-5368 or jim@evstudio.com for help. Anytime.

Spread Footing Foundation

Jim Houlette — Mon, 12 Dec 2011 23:46:24 +0000

This has to be the most typical foundation type with basement or crawlspace construction. The spread footing design is simple; provide sufficient footing area to distribute the weight of the structure onto the soil. Typically, a 16” wide x 8” concrete footing is used.

The width of the footing distributes the dead and live load of the structure on the soil allowing a typical 8” wide concrete wall to be placed on the footing in lieu of a wide 12” to 16” concrete wall. In addition, the poured footing helps to provide a level surface for the concrete foundation walls. The thickness of the footing will vary due to unlevel soil conditions. The designer should also keep in mind that even if a 12” wide footing satisfies soil bearing, the foundation crew may need at least 16” to allow enough area to set the wall forms on the footings and allow for dimension errors to be adjusted.

A typical spread footing foundation is also referred to as a ‘T wall’.

PROS
Cost effective
Common Construction
Low Tech

CONS
Fails with Swelling Soil

Learn more about different types of foundations

Originally posted 2009-09-13 02:09:33.

Wall on Grade Foundation

Jim Houlette — Mon, 12 Dec 2011 23:46:22 +0000

Simple and cost effective, but limited in design capabilities. A wall on grade is just as simple as it sounds. If the bearing capacity of the soil is moderate to high and the load from the structure is light then a typical spread footing can be omitted. In most foundations an 8” wide foundation wall is used so the bearing area would only be .66ft per linear foot. If the soil bearing capacity is 2,000psf the foundation could only support 1,332plf and that must include the weight of the foundation wall. Therefore, you will find in most situations that the wall on grade foundation can only support light structures.

I have used a wall on grade foundation for detached garages and small homes when saving every dollar counts. The walls can be constructed by trenching and setting forms as needed above grade or excavating for a typical crawlspace and setting forms for the depth required for frost depth.

The wall width does not need to be only 8”. You may find it cost effective to use a wall on grade that is 10” or 12” wide for a 36” tall wall in lieu of a spread footing. The volume of concrete may be higher for the wall on grade as the width of the wall increases, but you can construct the wall with a single pour in lieu of two pours; footing then foundation wall.

A wall on grade foundation can sometimes be mistaken as the same foundation type as a turn down edge slab-on-grade. The difference between a wall on grade and a slab-on-grade is the separation of the foundation from the slab. For a wall on grade the bearing area is only of the wall, and for a slab-on-grade turn down edge you can also take into account a percentage of the slab surface for bearing. You can read more about the slab bearing area from a previous discussion about post tension slab on grades and bearing area here.

PROS
Cost effective
Common Construction
Low Tech

CONS
Fails with Swelling Soil
Limited Design Capacity

Learn more about different foundation types.

Originally posted 2009-10-06 00:01:51.

Involving an Architect in Your Home Buying Process

Sean O'Hara — Mon, 12 Dec 2011 23:46:21 +0000

With the start of spring we're seeing more people buying homes and more people renovating homes. Buyers generally have a real estate agent to help them and frequently a home inspector but sometimes you need more licensed professionals, specifically architects, surveyors and engineers.

If you plan to add onto a house or do a major renovation it is important to talk to an architect before you close on the property. An architect can look at the existing layout, the setbacks and the zoning to see what your options are going to be. They can also provide feedback on your ideas and help you understand the magnitude of time and costs that you'll incur. If something seems odd with room sizes, head heights, window sizes or exiting you need an architect. Always better to know this before you own the home.

Remember for all their general knowledge, your home inspector is not a licensed professional. If there are any concerns about the structure, you should get a structural engineer involved. They can evaluate the issues and let you know if failures are cosmetic or serious. They can also work with you to understand the possibilities for repairs.

If you have questions about your potential home and the relationship to adjacent properties, property lines, fences and easements you should talk to a professional land surveyor. They can give you an accurate drawing of how these site concerns interact with your future home.

When we are involved with home buyers either as architects or engineers we charge our time hourly and can provide estimates on the number of hours required up front. If you end up buying the property that we look at with you, we can generally credit that time toward any work that you need designed for the home. On surveys we provide fixed fees and the survey that we do for you prior to the closing is often all that you need for any design work. If you have any questions feel free to contact us.

Originally posted 2010-04-21 00:01:34.