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11-18-2019, 04:09 PM #1
Rim board screwed into block wall
Floor system band joist (ledger board) for the floor joists have been bolted to the sides of the foundation block wall every 16" or so. Usually the framing is rested on top of the block foundation wall, reminds me of how a deck is attached to the house. This looks OK to me, but this was a 1950 built house that has completely been redone. I guess my concern would be that there's nothing underneath the rim board, I might of cleated a 2x6 up underneath the rim board every 8 ft. Any opinions ??
Similar Threads:Last edited by Sam Morris; 11-18-2019 at 05:52 PM.
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11-18-2019, 05:46 PM #2
Re: Rim board screwed into block wall
Looks like small tap cons, likely too small and too few, for that use.
Also looks like the block is hollow, if so, then the tap cons are only screwed to the block face shell itself, which is not intended for or rated for, that load. Did you try to reach up into that hole with the nm cables and see if the course of block above was solid or hollow?
Joist hangers are too small too.
Doesn't look right to me, anyone else see it better than I am?
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11-18-2019, 05:56 PM #3
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11-18-2019, 07:18 PM #4
Re: Rim board screwed into block wall
I'd recommend an engineer design appropriate repairs ... unless you are an engineer ... and give provide and signed and sealed engineering letter ... otherwise you could be signing and sealing your fate with such recommendations - I don't see how anything much is going to do any substantial amount of good unless that blocks which are anchored to are filled solid with concrete, and being as (I am sure) no fabric, screen, felt or other method containing concrete to only pour one or two courses with concrete, that entire stem wall may end up being filled with concrete ... but that should be up to an engineer to design, sign, and seal the engineering repair letter ... then ... (that letter is only a starting point) ... AFTER the work is done, have the engineer provide an followup letter stating that the work was done in accordance with the engineering design ... again, signed and sealed engineering letter.
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11-19-2019, 02:41 PM #5
Re: Rim board screwed into block wall
Just curious how/why the floor system is between the block foundation walls instead of sitting on it?
Is this an addition? Can't say that I have seen this type of framing before.
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11-19-2019, 03:17 PM #6
Re: Rim board screwed into block wall
As this is originally "a 1950 built house", I suspect that it may have had balloon framing, with the studs setting on a sill plate and going up to the top plate, with the original floor system having been at the level of a ledger attached to the studs at some point above the sill plate.
I have seen some older homes constructed that way, and, yes, fireblocking between each stud at the floor level was seldom done, or seldom done properly when it was done.
Doing a gut and renovate, they may have 'lowered the floor' as an easier way to: a) eliminate the need for that fireblocking; b) which effectively 'raises the ceiling' and give a higher ceiling inside. Some old houses did not have 8 foot ceilings, thus 'raising the ceiling' can make the ceiling heights compliant with modern expectations.
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11-21-2019, 05:05 AM #7
Re: Rim board screwed into block wall
Observation. Brick Masonry foundation. Either or, there are methods.
Question: Are the CMU units hallow?
Did you Tap on the CMU.
I use the handle of a Hard Plastic Screwdriver.
If hollow. There are construction adhesives to use on the Rim Board for such applications. The adhesives insure the load is evenly distributed along the full length of the Rim Board.
Write up the raised deck per/as usually.
No flashing.
Insufficient rim board ledger fasteners.
Wrong type of fasteners. No washers.
Wrong fastening pattern.
Just my 2 cents.
Robert Young's Montreal Home Inspection Services Inc.
Call (514) 489-1887 or (514) 441-3732
Our Motto; Putting information where you need it most, "In your hands.”
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11-21-2019, 09:36 AM #8
Re: Rim board screwed into block wall
Also the ledger needs to be of naturally-durable or preservative-treated wood per IBC Section 2304.
Thom Huggett, PE, SE, CBO
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11-21-2019, 05:22 PM #9
Re: Rim board screwed into block wall
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11-21-2019, 06:03 PM #10
Re: Rim board screwed into block wall
Looks like a typical flip job to me. The house may have been built in the 50?s but this looks like recent buy-it-cheap-fix-it-up-cheap then sell it as much as some sucker will pay.
The above statements are expressed solely as my opinion and in all probability will conflict with someone else's.
Stu, Fredericksburg VA
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11-21-2019, 06:14 PM #11
Re: Rim board screwed into block wall
Evening, Jerry.
I was not referring to code thank you to making that point clear. I was referring to construction adhesives and hollow core masonry walls if the CMU are hollow.
Thank you again for clearing that up.
Simpson Strong-Tie Anchor Systems. Strong Ties manufactures a full array of anchoring and fastening products for concrete and masonry ? including adhesives for anchoring threaded rod and rebar, mechanical anchors, powder- and gas-actuated fastening systems and accessories.
Robert Young's Montreal Home Inspection Services Inc.
Call (514) 489-1887 or (514) 441-3732
Our Motto; Putting information where you need it most, "In your hands.”
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11-21-2019, 07:08 PM #12
Re: Rim board screwed into block wall
Robert,
Adhesive anchoring systems are for solid concrete and/or concrete/grout filled block as concrete block is not intended for anchoring a load such as a ledger (maybe a picture, but not a ledger).
Face shells are intended for carrying vertical loads vertically down to the foundation/support that the block is laid on.
My main point of my previous question to you was about when you said this:
"If hollow. There are construction adhesives to use on the Rim Board for such applications. The adhesives insure the load is evenly distributed along the full length of the Rim Board."
"If hollow."
If hollow ... what is designed and engineered to be fastened to the face shell for construction and/or structural loads?
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11-21-2019, 07:22 PM #13
Re: Rim board screwed into block wall
Robert Young's Montreal Home Inspection Services Inc.
Call (514) 489-1887 or (514) 441-3732
Our Motto; Putting information where you need it most, "In your hands.”
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11-21-2019, 08:00 PM #14
Re: Rim board screwed into block wall
Robert,
You are completely and totally missing the point ... "hollow" concrete blocks are ... "hollow" ... and are not intended to serve as an anchor point for construction or structural loads.
Question: What is the minimum thickness of face shells on concrete block (ACI 530, if I recall correctly, was many years ago when I last looked it up)?
Answer: 1-1/4 inches
Question: How thick do you think most concrete blocks are for most of their height?
Answer: 1-1/4 inches. (Concrete block face shells and webs gets thicker in the bottom third or so to enable them to slide out of the forms at the concrete block plant - but are you sure you are anchoring in that 'thicker' part?)
Question: What is the minimum embedment of anchors in concrete block?
Answer: Here are some examples from various manufacturer's installation instructions and the code:
- Anchors for windows and doors - 1-3/8 inches
- Anchors for plywood used to cover windows and doors for impact protection from flying debris - 2 inches:
- - Table R301.2.1.2
- - - Windborne Debris Protection Fastening Schedule for Wood Structural Panels
- - - - No 8 wood-screw-based anchor with 2-inch embedment
- - - - No 10 wood-screw-based anchor with 2-inch embedment
- - - - 1/4-inch lag-screw-based anchor with 2-inch embedment
- - Note c. Anchors shall penetrate through the exterior wall covering with an embedment length of not less that 2 inches into the building frame. Fasteners shall be located not less than 2-1/2 inches from the edge of concrete block or concrete.
Followup question: A 7/16" thick (minimum) wood structural panel is to be attached to a wall with 1/2" stucco applied to concrete block with a 1-1/4" thick face shell - what is the minimum fastener length to attain the minimum required 2" embedment if the anchor screws are into hollow block?
You may be doing the math of 7/16" panel + 1/2" stucco = 1-3/16" to get to the block + 2" embedment into the block = 3-3/16". Is that what you got?
Here a problem: your embedment is only 1-1/4".
That's the thickness of the face shell, the screw would simply "stick through" the face shell of the block and would not do anything ... unless you could quantify the holding power of the "structural air" inside the block, which no engineer has yet been able to do.
Hollow block is ... well ... HOLLOW.
You would need a FILLED CELL before even bothering to do the math, and that math we just did is not 'to the tip of the screw' as the tip of the screw is not included in "embedment", only the length of the full diameter of the screw with full threads is counted.
Here is another question for you, being as you are/were a mason: How much of the face shell of the first course block is allowed to overhang its supporting slab/foundation?
Answer: ??
(hint: none)
Last edited by Jerry Peck; 11-21-2019 at 08:45 PM. Reason: Oops SCI 530, NOT ALARM 530
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11-22-2019, 04:00 AM #15
Re: Rim board screwed into block wall
Jerry, it appears you are missing the point.
You are correct referring to face shell anchorage.
What we do not know is a limitation thus far. Dimensions of the CMU block.
Actually, fastening can be archived at the web. The products in the link explain the manufacturers adhesive and anchoring technique.
I was a practicing mason. I was self taught. Literature purchased. I worked with masonry gangs for years in total hour count. Unfortunately I was/am English at the time living in a province that was hell bent on imperialist ideologies based on a fictional narrative somewhat like with you are going through now.
CMU Cutaway.JPG
Last edited by ROBERT YOUNG; 11-22-2019 at 04:07 AM.
Robert Young's Montreal Home Inspection Services Inc.
Call (514) 489-1887 or (514) 441-3732
Our Motto; Putting information where you need it most, "In your hands.”
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11-22-2019, 04:42 AM #16
Re: Rim board screwed into block wall
Picture #....324 appears to show block is filled.
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11-22-2019, 06:08 AM #17
Re: Rim board screwed into block wall
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11-27-2019, 10:55 AM #18
Re: Rim board screwed into block wall
I wholeheartedly agree. Despite thirty-plus years in the building trades I NEVER make specific recommendations as to the method or process of repairs. My lawyers have repeatedly cautioned about being to specific on remediation recommendations.
State what the defect is and that it requires correction, but refer to a qualified tradesman or engineer to determine the exact process for correction.
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11-27-2019, 11:08 AM #19
Re: Rim board screwed into block wall
Jerry, yep, bigger monitor look hollow.
A fix could be just adding a beam for support with posts on footer.
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11-27-2019, 01:41 PM #20
Re: Rim board screwed into block wall
FWIW, Jerry is hitting the nail on the head.
But one thing I don't think was discussed was that the fasteners don't provide adequate bearing on the WOOD ledger (setting the block aside for now).
Whatever is needed to support each joist in shear, say 1.5"x...1" or 1.5"? (depends on the load, and the dimensions of the hanger) also needs to be done at the nailing of the joist hanger to the ledger (i.e., assuming 1.5"long nails 1/8"in diameter, in my example, 8 or more would be needed to transfer the joist load to the ledger, (assuming the ledger is the same stress rating as the joist) and then ditto for the bolted connection of the ledger to the wall.
(Aside: if it is a pressure-treated ledger, its probably SYP and has a higher stress rating, but then what is the coating on those nails - how long will it take for the copper treatment to corrode the nails?)
Assuming there is only one bolt between each joist (so 1 bolt per joist), I suspect it offers only 3/8" bearing at best, which is considerably less than the 8/8" or more provided by the hanger nailing to the ledger.
Although construction adhesive is good stuff, how do you calculate that bearing capacity in shear? Especially if it wasn't clamped real good and tight, forcing it into both the ledger and the block?
Is there any data out there on that? My guess is "no".
Just my opinion, FWIW.
--
Richard
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11-28-2019, 10:21 PM #21
This may be too late but the block wall is not hollow...
If you look at photo DSCN3324.JPG closely you will see cell grout that has been cored. But agree with the others who have said the TapCons are undersized attachments and used improperly here, and the joist hangers are undersized, though this may be a short span with oversized joists for one of several reasons. No insulation, too.
Also trying to figure out why they went to the trouble of placing some sort of barrier behind the ledger and then tearing much of it away. You can see some material hanging down in two photos. My best guess is that was the electrician's doing.
(44.5 years as a carpenter and framer, retiring early next year)
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11-29-2019, 06:31 AM #22
Re: This may be too late but the block wall is not hollow...
What I see in that photo is a broken out face shell of a hollow block, with face shell which didn't break off projecting in from the edges (can even see the shadows from it).
I'll upload the zoomed in photo later as the screen capture off my phone is too large file size to upload.
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12-02-2019, 10:31 AM #23
Re: This may be too late but the block wall is not hollow...
Plain and simple as you pointed out earlier, regardless of the blocks, filled or hollow the tapcons are not going to cut it. In the area of WV I live they require 5/8" carriage bolts or cap bolts with 11/2" washers every 16" . Every county in WV has some different local codes and the IBC is the minimum guideline. We all have to remember that built to code just means it meets the minimum standard and these pics of this structure are not even close. It would be an easy fix just time consuming.
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