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Successful Surveys Continue to Shape the Future

One of the best tools supporting our role as your professional management team has been “quick surveys”. Over the last few months, we have completed three successful surveys with an average response of 20% of our active membership. Some may look at the 80% that are not weighing-in and wonder why this might be, but as surveys go, anything over 10% is considered successful. This demonstrates that delivering quick surveys in fax broadcast or eNews formats are a great way of gathering input and focusing in on your thoughts on topics.

In February, you received an opportunity to weigh-in on the topic of deck anchorage. We received notification that the published version of the IRC 2006 would include a provision that slipped by everyone during the close of the public review period. The code provision decreased anchor bolt spacing dramatically in walls over 8-ft in height. In this printed edition, Table R404.1(2) provides the Maximum Plate Anchor-Bolt Spacing for Supported Foundation Wall. As you can see from the table shown below, the overly-conservative approach taken in this update will ultimately impact the price of foundations for the entire industry. An amendment has been submitted by the CFA, PCA, NRMCA, NAHB and NCMA to have this table reversed. We will keep you informed on its progress.

In the meantime, here is a summary of how the group of respondents supported the need for this amendment and validated its purpose to the ICC.

Q1: How many foundations do you install in a year (average last 5 years)?

Summary: Based on the 87 respondents to this survey, an average of 41,306 basements per year (five year period) have been constructed or an average of 475 basements per year per company. The companies ranged from fourteen (14) building less than one hundred per year to one (1) company building between 5,000 and 10,000 per year. The majority of companies (54) produced between 100 and 500 basements per year.

Q2: Which guidelines or code are you under?

Summary: The majority of respondents (59) stated that they are governed by one of the IRC codes. An additional 48 respondents stated that they are under either a state-adopted IRC with amendments or a stand-alone state code. Eleven (11) respondents stated that they are governed by a jurisdiction other than the national building code or state code.

Q3: What method for anchoring the sill plate do you use?

Summary: The majority of respondents to this question use anchor bolts (79) while others use the anchor straps (38). Three additional responses were received noting the use of seismic straps.

Q4: What is the typical spacing between anchor bolts or straps?

Summary: This question resulted in two sets of spacings noted, that between anchors and that from the corner to the first anchor. The spacing between anchors were noted as 2-ft. or less (2), between 2-ft. and 3-ft. (13), between 3-ft. and 4-ft. (33), between 5-ft. and 6-ft. (11) and those 6-ft. and greater (47). Those responding on the spacing from the corner included a spacing of one foot (9) and less than a foot (4).

Q5: What depth of embedment and diameter of anchor bolt do you use?

Summary: Two parts to this question were answered. The first resulted in an overwhelming majority using 1/2-in. (95) bolts while only one company used 3/8-in. bolts and only one used 5/8-in. bolts. The second part resulted in a significant distribution of embedment depths split into three ranges. They were: less than 6-in. (65), between 7 and 9-in. (76) and greater than 9-in. (12).

Q6: What is the typical size of the sill plate used (if known)?

Summary: The responses received included 20 connecting to 2x4s, 61 to 2x6s and 9 to 2x8s as well as one to a 3×4 sill plate.

Q7: How many times in the past 5 years have you had a problem or failure of the sill plate attachment, including failure of the sill plate?

Summary: Only three respondents gave information. One stated eleven failures in 5 years, one stated 30 failures in 5 years and a third stated that the only failures occurred when the carpenters improperly nailed the joists to the sill plates. One respondent gave this comment “This is a nonissue!! In over 5000 foundations we have not had a single failure.” Another added “In 32 years of wall production (several thousand basements). We’ve yet to have our first failure. Had one house (tornado removed house) all that was left was sill plate still bolted to foundation.” Still another stated “In our area, builders water soak the back fill to promote settling without the floor joist in place or wall bracing. It’s very frustrating.”

Q8: What were the causes of the problems noted in the quantities above?

Summary: The responses to this question confirmed the most common issues our industry states as being the cause of foundation wall failures. These included:

· Large equipment to close to the wall

· Missed bolt or strap location fixed by drill & epoxy replacement

· Excessive water pressure during soaking of backfill

· Excavator hit the foundation wall during backfilling

· Backfilling damage prior to the sill plate and floor deck installation

· #1 failure was the attachment of the floor deck the sill plate

Q9: What was the remedy for the problem identified?

Summary: The respondents noted that of the walls noted as damaged, most were kept and concrete chipped out and replaced or the backfill was dug out to allow access to the wall for reinforcing with integrated pilasters or deadmen. Most responded with thoughts on how prevention was used to keep the issue from occurring again.

These included:

· Using additional reinforcement horizontally along the top of all walls

· Using wall braces on all walls over 24-ft in length

· Improving the framing to the plate with attachment plates or clips

As you may gather from these responses, we found significant support for endorsing an amendment to an issue that had been defeated at every other stage in the creation of the 2006 IRC. We hope to see this potential impact remedied before state and local jurisdictions have a chance to put this code into effect through their adoption processes. If building officials in your area consider adoption of the 2006 IRC, be sure to get involved and lobby locally for an amendment. You may always contact the CFA for support in this effort.

Thank you to all who responded to our survey. We hope that you continue assisting us in the effort to improve the conditions of our industry and shape the focus of what is your Association.

Jim Baty, Technical Director

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Concrete FACTS, a publication of the Concrete Foundations Association, is THE voice for residential concrete industry news, market intelligence, business strategies, technical solutions, product information, and other resources for professionals in the cast-in-place concrete industry. Subscriptions to Concrete FACTS is available to anyone involved or interested in the residential concrete industry as a service to your industry. Please contact CFA Headquarters to find out more about your free subscription or Email Us