Attaching a Ledger to Concrete Block

riles_jJune 14, 2007

I was wondering if it was OK to attach a ledger board to the concrete block foundation of my house? I read somewhere that you can just drill through the block and install a threaded rod with a washer and nut on it to hold the ledger in place. Any thoughts?

Riles

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deckman22

I would use tapcons to hold it in place then use post to footings. Masonry should not be used to hold up ledgers, it's been a point of failure on decks all around the country.

Al

    Bookmark   June 14, 2007 at 10:34AM
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riles_j

I'm not sure I understand your response. Are you suggesting that I do a free standing deck with footings up near the house in lieu of a ledger? I am also not familar with what tapcons are. Thanks for the response.

Riles

    Bookmark   June 14, 2007 at 11:21AM
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deckman22

Tapcons are a fastener for attaching to masonry. What I'm saying is you should not just use fasteners to attach a ledger to masonry, it needs to be supported by post. You could do a free standing design, but it's just easier to build by using the tapcons to hold the board in place while you install post.

al

    Bookmark   June 14, 2007 at 11:52AM
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brickeyee

"Masonry should not be used to hold up ledgers, it's been a point of failure on decks all around the country."

The failure is inadequate anchoring of the ledger to the masonry resulting in pull away failures.
Many have been caused by the use of lead shield anchors and lag screws, and many areas now prohibit this method for ledgers.

When fastened correctly there is no problem, and in some places if you put a footer near a house it must be as deep as the existing footers for the house.

Wedge or sleeve anchors are preferred.

    Bookmark   June 14, 2007 at 7:19PM
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john_hyatt

NO WAY would I use any kind of anchor to fasten a deck ledger to a block building, Brick your not thinking straight there are a lot of problems. The only way that would work is if the blocks were completly filled with creet after rebar was installed in stages.

I totaly agree with Al. J

    Bookmark   June 14, 2007 at 10:14PM
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brickeyee

As opposed to having to dig down to basement footers to install a deck footer?

All you need are the correct anchors.
Everyone goes to Jo's corner hardware and buys whatever they have on the shelf, usually by price.
Most of the time no one even checks what the actual withdrawal loads (the shear loads are almost always more than adequate) are for the anchors they are using.
I cannot tell you how many times I have heard the '3/8 inch should be fine, it's only a deck'.
I have testified at a number of failures as a PE.
Correctly installed into block, masonry, or concrete is fine.
Veneer brick is NEVER acceptable.
All it takes is a little engineering.

    Bookmark   June 15, 2007 at 8:42AM
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john_hyatt

Ok Brick your into what your saying I am not understanding this. What are the sleeve/wedge anchors going to fasten to?

I am thinking we are talking about hollow cinder block,are you recomending tieing to the 1/2'' walls of this block? J

    Bookmark   June 15, 2007 at 9:40AM
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riles_j

I am dealing with hollow cinder block, I think.

If I am going to go with a freestanding deck would I just pour some footers about 2' from the house and run an extra beam there and cantilever the joists 2', or should I offset a different distance?

Second, why do some codes call for these footers to extend to the depth of the house footing? I have no idea how deep my footing is and I really don't want to get into that. I am in Tennessee with a frost depth of under 2' so I would just as soon dig 2' for the piers an be done.

Third, should I go ahead and attach a ledger to the block wall so that the joists have something to connect to? Or can I just let the joist cantilever and stop just short of the house?

Thanks,

Riles

    Bookmark   June 15, 2007 at 10:06AM
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thedeckpro

There are NO fasteners that are approved for attaching a deck ledger to a hollow block wall. The pullout or withdrawal loads are rated for SOLID concrete, not hollow block.

The only correct way to fasten a ledger to a hollow wall is to "sandwich" the block with another ledger board inside the house. Then run 1/2" threaded rod through in the same pattern you would use on a regular ledger (16" oc, staggered w. 2 at ledger ends or splices).

Riles, the code calls for you to go down to the house footing depth because 2' out from the house is part of the foundation "over dig". Basically, this means the dirt there has been replaced and is not virgin soil. As such, it doesn't have the bearing capacity of virgin soil.

    Bookmark   June 15, 2007 at 5:30PM
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john_hyatt

Riles Man,if it were mine>> place the piers far enough from the wall for the beam to land on the posts, unless the wall goes in and out with some kind of a detail there is no need to fasten to it at all....or tap con a leadger to the wall just to keep it on grade and support it with posts of course you will need more posts not using a beamA free standing project like this will need some sway bracing to make up for not having a secure ledger in place.

    Bookmark   June 15, 2007 at 5:41PM
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john_hyatt

Yo DeckPro Guy,,cant you just see that>> outside leadger tapconed on second inside leadger set in place at just the right height and place, a big assss drill bit going thru the whole thing, threaded rod with double nuts and seal tightThen the tighten up,,Do the tighten up Yeah,,do the tighten up Im Archie Bell with the Drells from Houston Texas...

Impact set on slow,,,hmmmmmmjust one little turn more,,,,CR..RACK!!!! you just broke a whole course of mortor joints. Uppers...J

    Bookmark   June 15, 2007 at 10:42PM
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brickeyee

All you need are the correct anchors.

Here is a link that might be useful: sleeve anchors

    Bookmark   June 16, 2007 at 12:46PM
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mike13

Brickeye,

Re: "Wedge or sleeve anchors are preferred. "

Wedge & drop-in anchors are specifically NOT recommended for concrete block applications on the website you link to above.

http://www.concretefasteners.com/determine-fastener.htm

Block - all anchors except for the wedge anchor and drop-in anchor can be used in block.

To the OP,

Do you have access to the other side of the concrete block?

    Bookmark   June 16, 2007 at 3:20PM
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riles_j

I do have access to both sides of the block foundation. There is already a deck there and it has a ledger board attached to the block wall. However, the ledger board was pulling away as it was not fastened correctly. There are a couple of bolts that were put through the block with a washer on the inside. Those bolts seem to have held up OK. There is no cracking of the block or pull-through of the washer. It seems like they just didn't have enough of them, didn't flash the ledger board, etc. So it is failing.

I am just trying to figure out the best way to connect it when I put it back. The option I don't like is trying to dig to the depth of the house foundation as I don't where that is and don't want to dig any more than I have to.

I don't mind running a beam 2' or 3' from the house if that is best. The house was built in the '50's so would the fact that it is not virgin soil matter? I really don't think any of the soil under this deck was virgin, but I have no way to know that.

Any concensus here on what to do?

Thanks,

Riles

    Bookmark   June 17, 2007 at 5:46PM
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marcinde

Epoxy anchors are approved by all the counties in VA for attachment to hollow masonry. We even had one where we were attaching to hollow masonry block through brick veneer. I see no reason to put a beam and footers next to the house instead of using epoxy anchors on a ledger attachment.

Here is a link that might be useful: FFX county VA

    Bookmark   June 17, 2007 at 8:46PM
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riles_j

marcinde,

Great info! Thanks.

I have a large crawl space (4-5' clear) so I do have access to the back side of the block wall and am wondering if one of these types of fasteners would be better than drilling all the way through the block and installing another ledger board on the inside. Any thoughts.

Riles

    Bookmark   June 18, 2007 at 9:50AM
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brickeyee

"Re: "Wedge or sleeve anchors are preferred. "

Wedge & drop-in anchors are specifically NOT recommended for concrete block applications on the website you link to above.

http://www.concretefasteners.com/determine-fastener.htm "

And as posted immediately above you is the correct ref to the sleeve anchors that are recommended.
There are other wedge anchors that are suitable, just not from this manufacturer.

    Bookmark   June 18, 2007 at 6:42PM
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john_hyatt

OK Guys,birck and Marci, just what are these anchors going to anchor against or with or into??

I use the two part Hilti system to fasten in to creet on a regular so I am wondering what any fastener is going to fasten to in a hollow cinder block wall, are you talking about the 1/2'' walls or filling the whole void with epoxy. J

    Bookmark   June 18, 2007 at 8:42PM
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marcinde

john, tech specs are in the link I've shown below. Basically, if I understand this right the epoxy goes through the screen insert and creates a secure plug on the back side of the hole in the CMU (basically inside the cell). This epoxy plug has been tested enough that the county feels confident enough to list it as an approved connection, and (more tellingly) our structural engineer has taken our details showing threaded rods anchored to hollow block foundations via epoxy and given us a big fat P.E. stamp. Do I understand it 100%? Nope. But I do know that the Hilti HY20 is an epoxy anchor that we have used and that the county allows.

Hey, I'm just a designer. People with way bigger brains than me figure out what's safe and effective and I listen to them.

Dave

Here is a link that might be useful: Hilti HY20

    Bookmark   June 18, 2007 at 9:56PM
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riles_j

Thanks again marcinde. Did you install these types of fasteners yourself? It seems like you need some special tools for the installation. Do you how much these fasteners cost?

Any thoughts from anyone on whether these anchors are better than sandwhiching two ledgers front and back around the block. The sandwhich technique seems like it would have much better pull out strength, however you are weakening the block a little more by adding another drill hole to it.

Riles

    Bookmark   June 19, 2007 at 9:02AM
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mike13

Riles,

What is the length of the ledger board, what are the dimensions of the deck, what is the tributary area that this ledger board will be supporting, what are the local code requirements for dead & live loads, & what is the height of the deck (assumption is 4 or 5 feet corresponding to the crawl space but I guess it could be a huge drop-off).

Brick,

The "sleeve anchor" website you recommended (http://www.concretefasteners.com/anchors-fasteners/sleeve/index.htm) states both "Zinc plated carbon steel and 304 stainless steel" are available. Given his ledger board is most likely ACQ would the carbon steel solution react with that? If he has to go with a stainless steel anchor the tension strength is much less.

Also, on the link above it also states under Applications "Medium to heavy-duty fastening into solid concrete. Dead loads only".

Of course it does go on to give ratings for hollow block so that is questionable to me as well as their comment of "Dead loads only". What's up with that?

    Bookmark   June 19, 2007 at 4:19PM
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john_hyatt

YO Dave, that is an intersting conection, I wont use it,but its intersting. Way to go with the PE stamp,we all got to make a buck every now and then. I like Hilti stuff they go way past in R&D I am sure in Lab conditions those fasteners work and Hey you got code on em. Intersting, Thanks!! John

    Bookmark   June 19, 2007 at 5:40PM
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riles_j

I posted my deck plans in another post, but I will repost here. The ledger would runs along the house which is at the bottom of that sketch. The ledger is about 30' long.

My crawl space is about 5' and the floor of it sits maybe about 1'-2' lower than the ground under the deck. The deck will be about 3-4' off the ground. In the sketch I am showing a beam 2' from the house, however I don't like the idea of digging down to the depth of my house footing because I have no idea what depth that is.

Dead load 40 psf and live 10 psf is pretty standard.

Suggestions?

Thanks,

Riles

    Bookmark   June 19, 2007 at 6:04PM
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marcinde

If you have a basement, your footing will be just below the basement wall (*usually*). If you have a crawlspace, probably not as deep. I don't know, it doesn't look like you have that many footers to dig.

@john- to the best of my knowledge, the codes here are based on IBC, so we're not exactly doing things on the cutting edge here. Our engineer, who used to be a county engineer before going solo, trusts the technology and our crews enough to stand behind it. What did you mean by "we all got to make a buck"?

Dave

    Bookmark   June 20, 2007 at 5:35PM
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john_hyatt

Its all good Dave, I am thinking I will drift on over to my local Hilti shop and check that stuff out. J

    Bookmark   June 20, 2007 at 6:01PM
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riles_j

At this point the contractors here seem to split down the middle on what to do here. 2 seem to be saying do a free standing project and install a beam up close to the house. 3 seem to be saying it's OK to install a ledger to the block with the right kind of fastener. Although there doesn't seem to be any consensus on the "right" kind of fastener (wedge, epoxy, sandwhich 2 ledgers)

I think I am leaning toward installing a beam up close to the house as shown in my plans posted earlier in this post. I will probably attach a ledger anyway as it seems like it would be good to have something to attach the end of the joist to.

A couple of additional questions. Is there any way I could use the house ledger for stabilization against sway, or am I back into the same quandry? If not, how much sway bracing would i need and where would I install it? My deck is about 3'-4' off the ground if that makes a difference. I have seen some examples on piers spaced in a perfect grid pattern, but what if my rows of piers are not symetrical? Any thoughts on this?

Thanks again.

Riles

    Bookmark   June 21, 2007 at 9:14AM
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marcinde

riles- read through the pdf I linked to in an above post. A ledger is an acceptable way to get lateral stability, but you're back to how to attach it.

Dave

    Bookmark   June 21, 2007 at 4:36PM
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brooklyndecks

I've been following this thread, and I agree with your last message...a free standing deck and a ledger for backup support. you can even tapcon it in, as it's just ancillary.

steve

    Bookmark   June 21, 2007 at 6:47PM
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thedeckpro

riles, if you are looking for only lateral stability on the deck, a ledger attached with lag shields or big tapcons will do the trick.

John, I have done over 70 decks using the "sandwiched ledger" method. Never a failure or problem. Of course we don't torque the nuts down with a 1000 ft/lb impact gun.

In NJ, the ONLY acceptable method to attach to hollow block is the sandwiched ledger. Maybe those new Hilti fasteners will become approved here. But until then, we will sandwich :)

    Bookmark   June 27, 2007 at 10:21PM
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john_hyatt

I was just funen with ya Man, If the permit store goes for it Im good with it. In fact I am about to put an upstairs addition on my shop,same hollow cinder block,I am thinking I will do the sandwich thing after trying the hilti stuff. Man I just dont see how those hilti things could work but Im gunna find out.

I will be using the impact driver but I might just crank down the power to 999 lb. J

    Bookmark   June 28, 2007 at 11:52AM
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beyond_charter_net

Hi,
I been a superintendent for a general contracting company for a lot of years now, and I have seen & done just about everything... you can attach a ledger board to a CMU block wall hallow or not with SET22 Epoxy.. make sure your useing "SIMPSON STRONG-TIE SET22 Epoxy" we do a lot of work for goverment buldings and set22 is what the man calls for... when installing, you can install right in the grount line.... drill out a hole, install Opti-Mesh Adhesive-Anchoring Screen Tubes, fill full with set22 Epoxy... then slide your 5/8 all Thread-rod in the hole, turn the rod 1/4 and make sure the Epoxy set all the way around it.... let it dry and your good to go....

    Bookmark   March 11, 2011 at 1:02AM
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