walltech
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Posts:469
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| 11/26/2007 10:56 PM |
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| 11/25/2007 6:37 PM |
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Dave,
Could you provide more information on how you do your internal bucks. I have been doing research for a while, planning on building my own house. I could not decide which way to do my bucks but when I saw your pic, looks nice and clean and makes a lot of sense. How do you support at the bottom? Do you have other pics? No issues with hanging window? If you want to swing this to another thread let me know which one.
I plan on using Integraspec based on very good support locally. I know they have EPS bucks and headers but I don't feel comfy with this.
Tks
sly
Reply: Sly there are many reasons why we teach this method of bucking. First though I will point out a few reasons why some don't use this method. Some ICF's have to much compression to use this method, and many of the professionals on this site do the ICF only on there projects. Most of our customers are the ICF guy and builder and are still around when the windows go in and can simply understand this method and make it works well for them. The ICF guys are long gone when the windows go in and surely don't want to create a complaining contractor who doesn't understand this method.
I will enclose two pictures which will include the original picture that is being poured that you commented on and a closer up version of another to help understand the procedure. The benefits of an inside buck are as follows:
(1) No cross bracing of windows required which saves time and also impedes the workers from entering in and out of the doors and or window openings in a basement or on grade pour.
(2) The inside buck's shown are 2x6 Pressure treated which require no ripping in which power is not always available at an early stage of construction.
(3) This single buck method along with even a re-wrap is still less material cost than a 2x12 PT.
(4) This method allows you to install huge window openings by yourself one piece at a time.
(5) There is allot of room for error in the double buck application. (inner with a re-wrap) If you made an error which was discovered at time of re-wrap you simply add 1/2 or 3/4 ply to one side or the other to make up for the mistake.
(6) There is no thermal bridging with the single or double buck method. (explain further on)
(7) No warping of material at all!
As far as the methods goes first you will have to make the choice between single and double. Double will be the same principle as single but with a 3.25" larger R.O. As stated above the lumber in a inside buck is 2x6 (6" wall core) with the top (header) going across the top of the sides, the sides going under the top and beyond the sill, and the sill fitting in-between the sides.
If you pre-assemble the bucks together make sure you only screw the sill first on the inside and continue stacking block until you have crossed your window sills and your blocks lock in the correct running bond. Save the screwing of the remainder of the windows until wall alignment is in place and windows are square and plumb.
The bucks are screwed into place from the inside first with a 4" galv. coarse thread screw and a 402 ULP as shown in photo from Windlock at 8" o.c. Next we fill the gap between the outer ICF panel and the PT 2x6 with foam adhesive. By time you get all the way around the house the first window is generally set up. Next screw the outer foam in the same fashion with the same exact, and opposite pattern. You will be slightly inverting the ulp from its original convex design to concave. When you screw the outside screws the torque will slightly bow the foam in which allows the nailing flange on the window to be a little more flush with the foam.
Next if your going single buck you simply remove the outer screws and use them to screw the window in place. If your going double buck you can either re-wrap the opening with two 2x6's white lumber side by side which equals 11" again no ripping and a reason that works well with our forms. Or, you can place a 2x6 white lumber flush with the outside and a 2x4 flush to inside and fill the gap between with foam to impede thermal bridging.
Is there thermal bridging through 2x12 window bucks? There has to be some, we can easily see it in a infra-red scan of an ICF home at the top plate when it isn't recessed like single inside buck window method in photo and also see every outlet that is cut all the way to the concrete surface.
Next make sure you double buck your door openings or see next paragraph. You will want to have lumber to hit with your two long hinge screws that are provided for the top hinge. I would recommend replacing two screws on all hinges with the matching longer screws along with the doorknob strike plate which can easily be kicked in which will split the jamb with the standard 3/4 screws provided which don't reach the RO lumber.
You will also have to decide how to jamb your door openings. Doors with standard jambs will swing and hit the RO when half open if held flush to exterior with brick mold applied. Options here are many depending on door manufacture. Some hold door flush to inside and jamb exterior, and some flush 2x4 or 2x6 with 1/2 ply wood flush to ICF interior. This allows a factory jamb and sill, in which fore-thought can achieve many exterior finish options.
I will leave off with this and answer any questions you have.
Dave
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dmaceld
Registered Users
Posts:494
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| 11/27/2007 1:27 AM |
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Sure does look like a lot less work than 2 x 12 bucks! Obviously the screws every 8" must provide enough rigidity to keep the hydraulic pressure of the concrete from bowing the bucks or you wouldn't do it this way, right? I take it the foam adhesive is rigid enough when it sets up to keep the outer panel from bending in very much when you screw the buck in.
What do you do for the sill buck when you have the ties right at the bottom of the opening, like in the one window you show?
A photo tip, if you aren't already aware of it. The best way to cut down on file size is to save the photo with a jpeg quality level no greater than 80% (8 in some programs), or even as low as 60%. The drop in color quality is hardly noticeable. If that doesn't bring it under 100k then cut the resolution.
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Building house - what a way to spend retirement! |
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walltech
Registered Users
Posts:469
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| 11/27/2007 6:25 AM |
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Good question, that is also something I commented on in my early a.m. post yesterday that I lost due to the large picture. This method allows you to remove any ties immediately below the sill piece due to the buck is replacing the tie strength. Also note the small beads of glue on the horizontal block joint below the sill, this keeps the concrete from lifting that block up. The foam adhesive on the outside will crush and bow in to much if over tightened, but the glue does a good job of holding the outside without over-tightening.
Yes the screws keep everything dead solid. I have only seen one buck move on a double garage door opening where I was pouring for a first timer. I was filling the column between the doors and didn't realize the customer hadn't ran the buck down into the full block below the opening 6" or so. I was trying to use up the first wet load about a 8" slump with a new pump guy that was sitting on a very steep slope, which has a negative affect on the operators handling abilities when the truck isn't level.
He could not move quick enough and I filled the column all the way to the top. The side couldn't hold the wet head pressure and pushed out which was easily manageable.
Dave
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Buntly
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Posts:95
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| 11/27/2007 7:59 AM |
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Hello Dave, your pics do not show any support unter the lintels? Looks like some of the windows are maybe 4' wide or so and your lintels look to be 20" or so deep. You can actually pour and the lintels do not bow due to the weight of the concrete?
Thks......Bunt
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JohnCujie
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Posts:31
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| 11/27/2007 10:37 AM |
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This is an interesting idea especially if it eliminates a lot of bracing. I recessed my windows using a split buck with the outer half removeable. It would have been easier in the long run to use this method and applied a 2 x 6 later to get the recess. Plus I would have had wood to attach the stucco returns to instead of concrete. How are you permanently attaching the buck to the concrete? Is there a lot of time cutting out webbing to create a space for the internal buck?
thanks, John
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SLC
Registered Users
Posts:7
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| 11/27/2007 6:18 PM |
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Dave,
Thank you so much for taking the time to provide more detail and information. That's a lot of info in one post but that's what makes this site so informative for full timers as well as guys like me that are just looking at building their own house.
P.S. I see others are also intrigued by this method!!
Again thank you very much Dave for sharing your experience.
sly |
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walltech
Registered Users
Posts:469
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| 11/27/2007 10:41 PM |
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Bunt, yes windows over 3'6" need header support by either a vertical 2x something, or a horizontal support by a strong back method. Personally I quit using either many years ago. Trying to be cost effective and proficient ICF installs taught us neither method made sense, you would continually shrink your lumber lengths by cutting them to fit the next smaller window until you bought new again. We simply place a vertical ICF brace in the center of each opening and screw a block of 2" x 6" (the same ones over and over) to the back of the alignment/brace through the slots to hold up the header. As I'm typing this I looked in my laptop for a photo which shows this in which I couldn't find and I'm sure I have one at work which I will add later. We allow about 1/8 th inch compression out of our brand of ICF in which we simply leave it that much short before pouring.
John, as luck has it the webbing seems to only inter-fer about 25% of the time and is quickly removed with a new saw-zall blade. (fine tooth) As far as attaching the buck to the concrete either traditional method with nails or screws that meet your preference work the same as any buck method. Personally after 7 years I don't think this buck method will ever move.
Sly, thanks for the progressive attitude.
Dave |
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walltech
Registered Users
Posts:469
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| 11/27/2007 10:52 PM |
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Oh! Also we don't cut access holes in sills any more to fill with concrete. We drill small 1" inspection holes which when vibrated from the exterior with a wall banger will pull a six inch slump across a 4' window opening from one side. There are occasional openings that have to have better access or the sill removed when pouring which is another bonus to this method.
Dave |
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Buntly
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Posts:95
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| 11/28/2007 7:28 AM |
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Dave, thanks for your time and effort on this!!!!!
Bunt
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Quantum
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Posts:262
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| 11/28/2007 11:30 AM |
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This bucking method is mandatory when the cladding will be EIFS or cementious stucco. Wood bucking's expansion/contraction will cause cracks.
Only problem I can see is always ensuring the RO square & plumb. I guess you could build the blocks over the RO line and then mark/cut the foam, using that as a guide for the internal bucking.
I was trying to imagine not installing the buck before bracing is set and plumb. Gee, the lintel blocks would fall down. I guess screwing the top buck wouldn't impede brace adjustment so much. Then again, that's about the time I add braces.
Alot of people won't like attaching casements onto foam; even though it would make a tight seal, eh, foam? I guess communication upfront is important so you can allow for double-bucking if need be. I suggest doing the first screws on the outside, for more positive attachment of the window; not sure what the compressive strength of iso foam is, but I doubt it's as good as block. However you advocate intentionally bowing the foam in so the casement flange meets the foam? It should do this if the foam is in-plane... unless it's the screw-dimples that are the problem. BTW, for others here, in certain parts of the country like the PacNW, you can not use galvanized screws in PT wood, due to corrosion. Must use coated screws.
I really like your thermal break method with double-bucking. Seems like even better would be to put the 2x4 on the outside, as the smaller board would absorb and transmit less energy, although with 2.75" block it would only overlap the internal buck 3/4"! Not enough, unless maybe the 4 sides are screwed together beforehand. Even then...
Using a brace to support wider lintels is good, or you could use a wood I-beam with blocks under it. I am surprised to hear that you have only holes drilled in the sill. I'd taken the blocks on your sill to be span-supports over pour-gaps in the 2-by. The blocks would hold the 3 pieces of 2-by straight for install, remove for pour, and reinstall to hold straight until cure. Seems it would be difficult to get 6" slump all the way under the window, even consolidating there.
I don't understand what you mean by:
"and some flush 2x4 or 2x6 with 1/2 ply wood flush to ICF interior. This allows a factory jamb and sill, in which fore-thought can achieve many exterior finish options."
Thanks for the info on the Superior Alignment braces. I think I'll stick with Giraffe.
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walltech
Registered Users
Posts:469
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| 11/28/2007 8:33 PM |
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Quantum, the blocks in the picture are there because the customer cut there access holes (4") to close to the sides. The mix design we use would flow up and out those holes like a volcano. As far as the "2x4 or 2x6 statement above" I'm talking about the jamb issue. Roughing in the inner buck 3" larger each direction, then applying a double 2 x 4 or 6 flush to interior with 1/2 ply on the out side. This would accommodate a standard 4 9/16 or 6/9/16 door in-swing. This will create a larger area on the exterior inset to either return brick, lick and stick, real stone etc. As far as the alignment comment I think you should call me.
Dave |
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Quantum
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Posts:262
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| 11/29/2007 10:02 AM |
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Well done, walltech.
But I understand that's about double-bucking the jamb. I'm just not picturing where the plywood comes in, nor how this modifies the location of the door frame. I try to suggest steel door frames anyway to be cast in, but am usually not around that early in the design process.
Ya, setting it to the inside of the return allows full inward swing, and in fact here on the Left Coast thinking is starting to move to an outward-mounted outward-swinging door, for protection from tsunami. But you seem to be describing a third option. |
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walltech
Registered Users
Posts:469
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| 11/29/2007 6:15 PM |
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No I'm talking the traditional in-swing inside flush mount factory jambed door. ( And no you couldn't even open a out-swing door with 30" inches of snow, and I would think the wind in any state would rip it off its hinges?) Anyways, looking down from the top view:
Icf with inside buck 3" larger than R.O.
Next two 2x6 ea side and top flush with interior ICF.
One layer 3" wide rips of 1/2 plywood covering 2x material from exterior.
Now you have a standard 2x6 wall dimension 6 9/16 for a factory jambed door.
You either remove brick mold or not.
In this recessed mode you can return the outer ICF corner back to the door with thicker (brick, stone etc.) without interfering with the narrow margin created any other way.
Again, this just fixes door issues where 11'" jambs are not available, gets the in-swing flush to inside, maintains solid attachment to wood, eliminates an exterior extension, and eliminates an interior jamb extension in which the strike will mark the jamb.
Dave |
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Quantum
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Posts:262
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| 11/29/2007 6:38 PM |
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Ah, right right right. Double-buck for the door frame only, and bring the brick around the corner down the return. Still don't see the role of the plywood rip tho, unless it's a fastening surface for ties or neobrik.
We on the Left Coast almost never get snow due to the leavening effects of the sea. Lots of rain... never hurricanes or tornadoes here though.
But the threat of tsunami, as this is Earthquake Country. And the odd occasion when the internets get dumped on. |
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dmaceld
Registered Users
Posts:494
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| 11/29/2007 7:08 PM |
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For what it's worth here's a PDF showing the details of how I plan to buck & frame my exterior doors. There will be one change though. Based on the discussion in this thread I will probably replace the single 2 x 12 buck with the inside the block 2x6 and the double 2x6 or 2x6 + 2x4 as Dave describes.
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Attachment: Door detail 12-32.pdf
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Building house - what a way to spend retirement! |
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Jelly
Registered Users
Posts:274
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| 11/29/2007 7:37 PM |
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Out-swinging doors are good in hurricane country.
Dave - great thread. Those pics you posted, is that going to be a basement or a conditioned crawlspace maybe?
Mac - nice detail drawings! |
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walltech
Registered Users
Posts:469
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| 11/29/2007 7:41 PM |
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Dmaceld, thats exactly what I'm talking about! As I have read in your past post and know which brand of ICF your using I can really help you out! I have information even your manufacture doesn't have as to design specs, and also I spent 4 hours today with Helix and I'm telling you this is the only way to go.
Dave |
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dmaceld
Registered Users
Posts:494
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| 11/30/2007 1:25 AM |
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Posted By walltech on 11/29/2007 7:41 PM
Dmaceld, I can really help you out!
Dave
Did you get my email via the profile link?
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Building house - what a way to spend retirement! |
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walltech
Registered Users
Posts:469
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| 11/30/2007 8:13 PM |
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I may have gotten something today but I'm at the home office now! I will not see anything from this site till Monday at Walltech. But as I said we need to talk!
Dave
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Opus
Registered Users
Posts:51
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| 12/03/2007 6:54 PM |
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I am using 6" light gage steel C studs as internal bucks. It works just like the internal 2x6 but is a better fit. They also lock themselfs into the concrete because of the return lip on them. I secure them with Wind devils from Windlock using self drilling coated #8 x 3" screws from Grabber. I am recessing the stud and placing Trex over it to provide some thermal break. You could also cover the steel with two 2x6's if you need the wood to fasten to. I line between the steel and the concrete with some 6"wide foam used for concrete expansion breaks. This lets me drill through the steel with a steel bit without ruining it when it hits concrete. Once you drill through the steel then use a concrete bit for the Tapcon. This is just what I am doing. I don't want any wood , this is much cheaper than V-Buck, and requires a whole lot less bracing. I have a friend who tried this and used a single 2x4 vertically and a single 2x4 horizontally to brace the insides of the bucks. He poured with no problem. Your milage may vary so use your own judgment on this.
Opus |
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