How To Attach A Timber Frame To Concrete Foundation - Pt. 2
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- čas přidán 5. 11. 2021
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What if you don't have an engineered flooring platform, and need to attach your post directly to concrete?
In this second video, Gaius shows two alternate options using metal fasteners to attach your timber frame structure directly to a concrete foundation.
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If you follow the advice in this video on how to locate the three post mounting holes you will be off 1 inch or the thickness of the stand-off.
And this advice is from the expert, only I,m not sure of what.
I was thinking the same thing. You can actually see the difference on the video. Yikes!
I came to the comments to say the same thing.
Good observation
Was it because the 1 inch spacer was not accounted for?
In traditional Japanese buildings there are four corrosion mitigation techniques that I recall:
1. Wrap the bottom of the post in a decorative copper sheet.
2. Mount the post on a stone (stones don't transmit moisture the way concrete does).
3. Char the bottom of the post slightly with fire.
4. Dip the lower end of the post in a bucket full of potent pesticide.
@Tom be careful burning the pesticide soaked wood! Probably char first, and soak past the char line
@Tom If I remember correctly, it's only the last 6"-8" of the end grain but not burned too much, cause that could weaken the end grain or cause it to crack, especially if you're going to drive any hardware through it with a metal standoff base. I guess if you burn it outside it isn't too dangerous, but idk if it's worth the risk of breathing that crap in
@Tom Actually, I've never seen the ends of posts charred in home or temple buildings. That doesn't mean it isn't done, though. The carpenters I worked with in the Ryukyu Islands dipped the ends of the posts in pesticide. All the charring I saw was on siding. So, maybe ask around a bit for more info.
That’s really smart. Isn’t the practice of burning to improve water resistance called shou sugi ban? I have heard a tip from Matt Risinger that if you prime the end grain, that helps to prolong its service life.
I have done many timbers installations using knife plate connections in a floor slab. As these plates are designed so that when the pins are driven into the timber and through the plate holes it creates a snug fit to prevent movement, this can all easily go south if your positioning of the knife plates when anchored to the concrete is out at all. The members of the frame will not square to one another and neither will your joints be tight. Your installation begins with this crucial step and it is not as easy as positioning the plates on the slab, marking the appropriate holes for the anchors then simply drilling away. I have found that masonry bits for this purpose can be notorious for drifting as you drill. You can not simply shift your timber on the knife plate to accommodate this offset. The only allowance you have is if the size of your anchors permits some wiggle room within the pre-drilled knife plate holes so you can properly align your plate according to the plans. Knife plates are a well engineered system but, like anything you build where precision is critical, controls for each stage, that may not be immediately obvious, will determine the success of your build. Hope this helps.
That looks like a nightmare to get right without a drill press-like accessory so you can be certain the bit is absolutely perpendicular to the beam. It's definitely a good looking mount though.
Wow this is good advice!
@@incognitotorpedo42 Yes and yes.
He went over the anchoring to concrete part in like, half a sentence haha
hi do you know of any resources regarding finger joint connections for mass timber construction by any chance?
Ty. Half my enjoyment watching you folks work is seeing-almost smelling-such beautiful wood. It's great!
You need to get out more
This was great and super helpful! Thanks for sharing the knowledge!
Very helpful video! thank you for posting.
Thanks for a great demo of these anchors. We live in the UK so don't get much dry weather and planning to build a light weight roof lean-to car port but unfortunately need to site the posts on top of a short retaining stone wall. Is it okay to build a small brick base (min foot print of 1x1 ft sq, 4 bricks high) for each post, and fill these concrete to bed each anchor? The retaining wall approx 2ft wide, very strong with reinforced footing. We hope using old solid bricks for each base will add character and keep the timber high enough to avoid rain splashing up off ground level. Our only concern is if it's strong enough to withstand strong wind. Appreciate and help/advice. Thanks again 🙂
Thanks for the explanation.
This is very helpful. Thank you.
Hi, I like how you simplified post installation. I wish to build a 12x12 covered deck using round cedar logs as posts. Please let me know how to install these posts that will support the deck and roof. Thanks.
Great information!
Thank you!
Really liking all of your videos, I have been watching the series as well as these instructional and the shorts. I currently work for Seagate Mass Timber in BC Canada, we do primarily institutional projects like community multiplex’s, we are going to Victoria in a few days to do the Royal BC Museum as well as the National Center for Indigenous Law. It’s fun and the end product is awesome however I always think about wanting to do residential, it seems more intimate working with a homeowner and I really want to build our home post and beam. We just need to pay off the land and finish saving for the build, this also makes me want to take your course 😁
Thank you for watching! We’ve got a lot of new educational content and build series coming in 2024!
i want to build a pole barn garage with sonitrol foundation...... good advice.....great way to foundation and attach in limited access
2:49 is a MISTAKE in the video. It has to be done with the black spacer on.
I want to anchor a porch swing to 6x6 post on concrete piers . I need lateral strength of course, should I use any of these or go without? Thanks
Thanks
I was using Simpson Strong-Tie products before you were CONCEIVED! I built mobile homes back in college for a summer job and we installed them and "tied them down" with Strong-Ties to concrete piers. My boss (the company owner) gave a lifetime warranty that our builds would withstand Okra-Homer tornadoes and not tear-apart and blow-away if they were on our installs. We never lost a one, even in an F-5 tornado that leveled EVERY stick-built house in a small town on the block, our two mobiles were FINE! Some interior sheetrock was cracked and wood paneling cracked, but that was all. They said there were 130+MPH straight winds in that gust front. I saw a semi tractor in what was left of about an 80 foot tree-a fridge literally "wrapped around" a tree trunk like a second-skin. A two-by launched thru a brick fireplace like a toothpick thru a piece of cheese, water pipes sticking up thru slabs twisted and squirting like "modern art".
It sounds like if the damage was that bad, the tornado must not have directly hit the mobiles
Interesting how would you frame around those post bases
I think it would be important to place the spacer on the anchor before marking the three holes. If not please explain.
That is correct.
I was just coming on here to make the exact same comment. Good catch
@@ShelterInstitute Then edit the video!
Do options exist to repair a post base (that meet code) and does not require removing the wood post itself?
I have a question regarding how you treat the timber frame to prevent termites.
Can a 14x20 be built on sleds like this? What is the easiest and safest way possible if one can’t do sonotubes or a foundation?
Will this pass code for a permit for a patio in california?
I've learned over the years when cutting the knife bracket space - cut 1/2" beyond the bracket size and mitigate splitting.
So you mean cut deeper by a half inch?
@@smolboyi yes
What about the CB66 anchor. Is that one better for say a timber garage 20’ x 20’
I built a timber frame, and missed my 8x8 tie downs by a few inches. But your video helped; ill thru bolt the fix.
I am using 2 x Simpson Strong tie (shiny metal option) for 2 - 8x8 Cedar posts supporting a 12x12' patio. During high-wind events, I have observed what I believe is slight lateral movement of the patio roof structure. Believe this is caused by the 2 Simpson strong ties allowing flex at the connector (it acts as a pivot) vs greater structural stability if the posts went into the ground providing increased vertical stability. I've considering adding some decorative corner bracing to counteract this natural force.
Yes, the metal is too thin. The design is excellent, but the steel needs to be at least 3 times thicker.
@@grc5618I was thinking that both of these designs showed look a bit weak..
Same here! Simpson 6X6 post ties. Wobbly as heck, so I've been considering corner braces. Did you end up adding corner bracing and did it help?
I am trying to figure out how to Secure an 8x8 mailbox post. Any suggestions??
Boards 5cm by 30 cm and 5 meter long, placed horizontaly (30cm being vertical) for building a horizontal roof, would they bend from their own whight or under snow ?
Can you add a 8x8 timber column to an existing concrete slab without a footing? I would like to add vertical post an beam with parallel beams.
If it is a load bearing column, it needs a proper footing.
There are so many builders/framers out there who need to see this. I can’t stand seeing timber just sitting on the slab of a walkout or stuck in the concrete pier when it was poured.
When you demonstrated the knife anchor and how to locate the holes in the column you forgot the 1" offset material. If you located the holes as you showed it would they not be
one inch off?
I was thinking the same thing.
Do these prevent rocking back & forth? To me it looks like the post could wobble
The timber frame itself keeps the post stable. This hardware only resists lateral and uplift forces.
It’s way better to set your post 30” in the ground, so the load is transferred to the ground instead of the slab.
What are those spacers made out of?
Most are made of galvanized steel, some light duty versions are made of plastic.
2:50 don't you need to also add the base cover to place those 3 holes correctly?
Here's the most important thing to consider and figure out - how to cut a 3/16" thick by 4 3/4" (+1/2") deep slot for the plate - a chain saw and jig will work for large posts and 1/2" plate , however, does anyone have any good ideas for cutting in the smaller slot for a saddle post of the size demonstrated in the video? Great demonstration video endorsing the product, but how about some real world examples of how to cut the required slots in oversized materials that cant't be run through a machine!
One idea is to drill a line of holes to the needed depth, spaced as close as possible and cut remaining material with the chisel. It's probably possible to do the same using a router, although depth might be problematic.
@@tjurzyk you have a chisel that can cut deep into a 3/16" slot? Is it 1/8" thick?
The Makita 5402 or Skil Super Sawsquatch beam saw both swing a 16 5/6" diameter blade (414mm). Max depth of cut (with shoe square to the blade) is on the order of 6 1/4" (160mm). If the shoe is angled, the depth of cut would decrease accordingly, though that isn't relevant for this application. You could treat this like cutting a drop cut tenon - a couple of kerfs to define the edges, then (in this case) chisel out the wood between. I've never used the Makita branded blades, but Joe Miller of Fire Tower Engineered Timber has advised me that the Skil blades are the pick of the litter for these saws, and I took his advise. Be aware that these are 20amp saws, and you can easily trip a 15amp breaker if the blade binds in wet wood. Thankfully, they turn fairly slowly compared to a 7 1/4" saw. Mafell also makes some lovely stuff, but a (very) used 5402 (the old, gold-colored one, not the blue plastic 5402NA) was more within my budget. I got my 5402 cheaper than a Super Sawsquatch kit, which was all that was available from Skil at the time, and I would still have needed to acquire an 8 1/4" Skil, since I only had an old Model 77. I still need to machine a good replacement shoe from aluminum plate for the 5402 to replace the flimsy/fragile stock stamped sheet metal one, though - then it will really sing. Projects, projects...
For a short tutorial on cutting a drop cut tenon with a beam saw, see Francis Barnett's video, here:
czcams.com/video/1nfTS2TWEhs/video.html
Francis has other good content on his channel, including kerfing joints to close them up if the initial fit-up isn't so great, and a bunch of basic timber framing joints. Worth a look.
A Prazi chain saw attachment for a circular saw might also work, though some have complained about accuracy of cut. This may depend on chain grind and the individual user - I've never used one, so I can't say. There was an earlier brand which I can't remember at the moment (rats!), conceptually similar to the Prazi, but requiring a dedicated conversion of the saw (as I recall, only a worm drive Skil could be used). You might spot one of the old ones on ePay, CL or Marketplace or your local equivalent; they do still show up from time to time - I've seen two within reasonable driving distance of me within the past couple of years.
You can use a jig (commercial or homemade) for a chainsaw to provide a shoe perpendicular to the bar. With a decent electric chainsaw, this would be a nice option for sundown use in a residential neighborhood - unfortunately, the nice 220volt Scandi or Japanese saws are pretty rare. Slow and steady, even with an anemic 110volt saw, would work in the right hands, with due care and a good rip grind on the chain. For DIY versions of such a shoe, look for fellas who are using a jig to cut half or full dovetails on cabin logs with a chain saw. There are some simple and good-looking designs out there. The DIY one posted by user "shinnlinger" on the Forestry Forum looks ace - basically two lengths of suitably relieved angle, bolted to the bar.
Or, you could use a sharp hand rip saw (a large Japanese pull saw would be nice), along with a narrow chisel and patience.
Hope one or another of these ideas will get you headed in the right direction. Your instincts are correct - bring the tool to the work, rather than the work to the tool.
It's not 3/16" thick steel. It's thinner than the kerf of a standard cross cut blade on a skill saw. You then use a hand saw to finish the job.
A code question about separating the post from the concrete: is it true that in an indoor location you just need a vapor break (e.g. sill seal or tar paper), but outdoors (e.g. a porch or patio) you need the 1" lift?
Additional question: in a building with posts around the exterior, plus posts in the interior of the structure, do you need to anchor the interior posts? or is it sufficient to anchor (for lateral and uplift resistance) to just anchor the perimeter posts?
Did you find an answer?
What if you want to build with 12x12s?
Why wouldn't you?
Would this post installation work for a mailbox post on concrete?
We’re making a video about this soon!
Great video! PLEASE - what is that black plate called that goes b/w concrete and wooden block?
Simpson Strong Tie CPS Composite-Plastic Standoff Post Base
@@ShelterInstitute Thank you so much :)
Instead of a concrete slab, would this idea still work if it was being attached to a stone as part of a stone wall foundation?
The drilling and attachment would be the same, but the trouble with stone is that you are only attaching to one stone. Therefore you will not get the same uplift or gravity load capacity.
My engineer engineered my carport for the 6x6’s to be installed in the concrete. I’m kinda worried why it was engineered that way. I’m afraid the post will rot over time being in the concrete. Should I be?
That depends on where you live and what type of 6x6's you use. Probably want to go with ground contact rated. You can also wrap them in plastic or seal them up with something.
I recently replaced my fence posts. They had been out for about 40 years. The wood was fine other than right where the wood soaked in the wet grass, snow and mud. The wood off the ground was able to dry and was fine.
Check your local building code.
These are great ideas, but in my experience the guage of steel you are using is approximately 3 times too thin. For large posts that metal needs to be at a minimum, 3/16" thick, 1/4" preferred. In high winds those 'tinfoil' brackets are going give, and no amount of upper gussets are going to hold back the force. Excellent idea, great designs, but WAY too thin of material.
in 2:56 he shows how to find drilling position for 3 holes to mount knife plate. But this will be bad idea if u want separator as shown in 2:37
hi, what is this metal part's full name? thanks
Concealed Post Base
Also called a knife plate.
You forgot to slide the base on the bracket to get the holes in the correct location. They would be an inch off the way you demonstrated. Oops!
opopp
the post on right is out of square to the base ! jus saying lol
At 2:40 minutes, his instructions on drilling the wood using the 3-holes metal plate as guides, will not guarantee correct alignment. I can guarantee that none of your drilled holes will align with the metal plate’s holes.
The 8x8 concealed post brackets are absolute garbage. I've got two posts wobbling in the wind. It's not like I didn't follow instructions or do shoddy work either. It's simply a very bad design.
3 dry wall screws and it will last forever. Lol. JK.
@@supermo26 Right? haha
Wobbling at the top? Seems like a bad structure design, the bottom of post shouldn't wobble, or is it?
@@tranderrick The whole thing is wobbling, including where it attaches at the base. Just a single free standing post wobbles when attached with these.
“Code required thing”
Yes, Simpson Strong tie are code complying products, provided you are using the product correctly.
Bullshit tinker toy brackets. They should have named them floppy post brackets.
Your bracket holes are not right on the concealed bracket , If you do what you stated and then drop in your one inch fill , You are one inch out with your holes, Put bracket on then measure for holes. Holy that could cost money to people watching your vid
T rex is nicer
Skills needed zero!
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I am trying to figure out how to Secure an 8x8 mailbox post. Any suggestions??