[sil_plate]

I was not sure about posting this here or in general discussion. If I'm wrong please move it.

I have been learning about random things about building houses, but I'm going back and learning from the ground up. There are a lot of tiny details that I am always wondering, but can never find answers. So I thought I would register here to maybe get some answers.

This is probably a very silly question, but it is so basic I never see it addressed. When placing anchor blots in a concrete foundation how do they ensure the bolts are in the center, and that they are consecutive? What is the procedure?

Are round washers allowed over sil plates, or is that code violation? Aren't all washers supposed to be square by today's standards?

I was also wondering about ventilation codes for crawl spaces. How far apart and what is the minimum amount of openings for crawl spaces to let them breathe and dry out moisture? What is the standard? Obviously it differs based on size, or I would imagine.

 

[joecaption]

#1 Go back and add your location to your profile!
#2 You need to be asking your local building dept. these questions. There the ones going to have the final say, differant areas, differant codes.
Never heard of anyone using square washers.

 

[sil_plate]

You've never heard of square washers over sil plates? They are larger and help hold the plate down better. They displace pressure I would assume.

#2 You need to be asking your local building dept. these questions. There the ones going to have the final say, differant areas, differant codes.

But I don't plan to live here, and I'm not really building a house. I live in OK it does say that on my profile. I'm really just curious about different areas, which is why I didn't specify. I was hoping people would answer based on their location to give me an idea of some differences.

 

[jomama45]

I was not sure about posting this here or in general discussion. If I'm wrong please move it.

I have been learning about random things about building houses, but I'm going back and learning from the ground up. There are a lot of tiny details that I am always wondering, but can never find answers. So I thought I would register here to maybe get some answers.

This is probably a very silly question, but it is so basic I never see it addressed. When placing anchor blots in a concrete foundation how do they ensure the bolts are in the center, and that they are consecutive? What is the procedure?

I place a lot of anchor bolts, but I'm not sure I understand the question. Simply put, "we" put the first bolt about 10" off of the corners (outside of wall) and either 48", 64" or 72" for the remainder of wall. We typically hold the bolts up 2-2.5" (depends on the carpenter's preference) and favor the outside of the wall with them, as most sill plates are narrower than the foundation wall. Like anything, there are some variances depending on what's designed, what the conractor wants, etc...

Are round washers allowed over sil plates, or is that code violation? Aren't all washers supposed to be square by today's standards?

Far less concern here with "uplift" from high winds than in OK, so round washers are still allowed here.


I was also wondering about ventilation codes for crawl spaces. How far apart and what is the minimum amount of openings for crawl spaces to let them breathe and dry out moisture? What is the standard? Obviously it differs based on size, or I would imagine.

I'm sure there are some ratios available in your own state code, but I can't comment on the use of vented crawlspaces here, as they're very uncommon here and are typically conditioned like the rest of the house.......

 

[jomama45]

#1 Go back and add your location to your profile!
#2 You need to be asking your local building dept. these questions. There the ones going to have the final say, differant areas, differant codes.
Never heard of anyone using square washers.

Rather than come across as being rude to relatively new member, asking perfectly legitimate questions on a DIY site, maybe you could simply resist the apparently overwhelming temptation to hit the "POST REPLY" tab and move on to a thread where you might actually have something constructive to offer, or maybe just log off of the site for a while??????:whistling2:

 

[Underdog]

As Joecaption stated, the correct answers to your questions depend on your local building code. However, in California, we require square washers and here are the requirements for my municipality:

Foundation plates or sills shall be bolted or anchored to the foundation with not less than ½ inch diameter steel bolts or approved anchors space a minimum of 6 feet on center for one and two story dwellings and a minimum of 4 feet on center for three of more story dwellings. There shall be at least two bolts per plate that start within 12 inches or 7 bolt diameters of the end of the plate. All foundation bolts shall be embedded a minimum of 7 inches into the concrete or masonry. Each bolt shall have a properly sized nut and washer. 2010 CRC, Section R403.1.6 & R403.1.6.1. The washers must be a minimum 3 x 3 inches square and .229 inches thick. A diagonal slot is allowed of a width 3/16 inch larger than the bolt diameter and a maximum 1-3/4 in length, provided a standard cut washer is used between the nut and plate washer. 2010 CRC, Section R602.11.1.

Regarding how to keep your sill bolts in place during a pour: This article gives you a few good options.

http://www.finehomebuilding.com/how-to/qa/location-of-foundation-bolts.aspx

And finally, crawl space ventilation varies depending on where you live and your local building codes. Keep in mind that California is relatively dry, so your area my have different ventilation requirements. For my area, this is what is required:

Provide a minimum of one square foot of under floor ventilation for each 150 square feet of under floor area as per 2010 CRC Section R408. One ventilation opening shall be within 3 feet of each corner of the building. The ventilation openings shall be placed so as to provide cross ventilation of the under floor space and be covered with materials with openings measuring a maximum of ¼”.

 

[sil_plate]

jomama, you pretty much answered my question. Thanks.

Another thing I was curious about you actually brought up. Like you said a lot of sil plates are more narrow than the foundation wall.

Don't you typically want the anchor blot in the center or mostly in the center of the plate? And if this is the case how do they know exactly where to place the bolt in the wall so when you lay the sil plate over it the bolt resides mostly in the center?Do they simply put the board on top of the blots and go down it hitting it with a hammer to mark the holes for drilling? Do they just measure the distance of each anchor bolt individualy as they place them? I'm just curious how precise anchor bolts are or have to be.

@ loftezy, thanks for the good info appreciate it. I know different locations have different codes, but I am simply learning about different area and state codes not researching to build.

 

[Underdog]

Don't you typically want the anchor blot in the center or mostly in the center of the plate? And if this is the case how do they know exactly where to place the bolt in the wall so when you lay the sil plate over it the bolt resides mostly in the center? Do they just measure the distance of each anchor bolt individualy as they place them?

When a person designs the foundation, they specify the size of the sill plate. For me, my last sill plate was 2x6 and the stem wall for the foundation was 8 inches. And since the sill plate is placed on the outside perimeter of the stem wall, this means that if I placed the bolts in the center of the stem wall that they wouldn't be in the center of the sill plate. (Following me?)

So, this means that the sill bolt will be placed at 2.75 inches from the outside perimeter of the stem wall in order for it to be in the center of the sill plate.

 

[sil_plate]

When a person designs the foundation, they specify the size of the sill plate. For me, my last sill plate was 2x6 and the stem wall for the foundation was 8 inches. And since the sill plate is placed on the outside perimeter of the stem wall, this means that if I placed the bolts in the center of the stem wall that they wouldn't be in the center of the sill plate. (Following me?)

So, this means that the sill bolt will be placed at 2.75 inches from the outside perimeter of the stem wall in order for it to be in the center of the sill plate.

Yep, that answers it. LOL Thanks!

 

[jomama45]

Don't you typically want the anchor blot in the center or mostly in the center of the plate?


Yes, but it certainly doesn't need to be perfect.

And if this is the case how do they know exactly where to place the bolt in the wall so when you lay the sil plate over it the bolt resides mostly in the center?

When you deal with measurements as a career, you ca easily guess 2-3".

Do they just measure the distance of each anchor bolt individualy as they place them?

You can measure and leave a "scratch mark" in the wet concrete where the next bolt goes, but most of the time it's just second nature, as wall forming systems are modular, and each form is generally either 2', 3' etc... Obviously, fractional forms are used as well, but the size is generally known as well, so it's simple math. Again, the bolts don't have to be exactly 48" on center, just close...........