Lifting a wall onto sill plate gasket
AdamPNW
| Posted in General Questions on
Hi all,
Our exterior walls will bear directly on the foundation perimeter wall with a single sill (bottom) plate.
I am planning to frame the walls on the ground and lift them into place, probably by crane, onto the embedded anchors.
How do folks usually prepare the sill plate gasket/seal before the wall is set down into place? I’m worried that things will get moved/smeared during the process. Any tips are appreciated!
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Replies
Adampnw,
The easiest way to make sure the sill-seal stays aligned and continuous is to staple it to the bottom plates before lifting or tilting the walls into place. If you are using a proprietary gasket from somewhere like Conservation Technology, it may have specific installation instructions you should follow.
Thanks Malcolm. On your advice I spoke with a rep from Conservation Technology and they also recommended stapling the gasket to the underside of the sill plate. He cautioned me to avoid moving the wall too much after the gasket is compressed or it will tear. An alternative would be to lay it out on top of the wall first and rely on the anchors to hold it in place.
Six of one, half dozen the other. I stapled mine to the bottom of the plate before tipping the wall up using wall jacks. I made sure that I was lined up, holes were drilled for the anchors, and an X cut where the Conservation Tech gasket met the anchors. I went this route over laying the gasket on the ground to avoid having to realign the gasket in case it got moved or bumped in the lift. It worked just fine.
I've never craned a wall into place (mainly because I've never had a crane) so there might be some considerations there that I'm not aware of.
Thanks Andy. Well I may be able to use wall jacks, but I keep thinking that my walls are too tall for that. They are balloon framed 2x6 walls, 17’ tall. I can frame them in 15’-20’ lengths, that would put the sheathed weight somewhere around 1000-1500 lbs.
Is there a height restriction on wall jacks that you’re aware of? Or is it just a matter of risk tolerance?
That's a tall wall! The tallest I've ever gone was about 10' which was no problem. The old school Qualcraft wall jacks that I have run on 2x4's as the poles so the length of the 2x4 is the real world limit. That said, you could connect to a window ledge I suppose, but I've never had to do it. So yeah...risk tolerance would increase greatly in that scenario.
There's an infinite number of options for technique here, sheathe the top section after tipping the walls up, lift smaller sections, etc but they all have pros and cons.
Andy, thinking about this some more…how are you able to get the wall to lift up and over the anchors using wall jacks? I would think the anchors are too high to simply tip the wall onto them.
Can you share more about your technique?
Adam
AdamPNW,
Here's what I do with tall walls on slabs.
- Set a 2"x6" on the slab against the anchor bolts.
-Snap a chalk line on it where the inside face of the bottom wall plate will sit.
-Lay some metal banding (from a lumber delivery) on that 2"x6" every 6 feet or so.
- Frame your wall on the slab so the bottom plate is sitting on the flat 2"x6" against that line.
- Bend the banding up and nail it to the bottom of the wall plate, and to the 2"x6" laying on the slab.
- Staple your sill-seal to the bottom plate.
- Sheath the wall.
- Stand the wall. The 2"x6" and banding will keep the bottom from kicking out and it should tilt right onto the anchor bolts.
- Cut the banding and pull out the 2"x6".
I did drop a rather tall wall on my friend Mike's leg, and he still sometimes complains about it. Come on Mike, it was over two decades go. Let it go.
This is great thank you. But to make sure I understand correctly, I’ve drawn a sketch. Can you confirm that the band is in the right place? I’m trying to also make sure the band does not get caught under the wall after the lift.
AdamPNW,
No unfortunately it has to go the other way or the band will just buckle. The upright leg of the L is attached to the underside of the bottom plate. You do end up with short lengths of the band left between the bottom plate and the sill-seal. I guess if you wanted to avoid that you could bring that leg right up and attach it through the sheathing to the outside face of the bottom plate, but leaving those short lengths of banding does no harm.
I guess it really depends on how much your anchors stick up. The center of a 2x6 is 2.75" and the anchor only needs to stick out by about 3" for a single sill plate. Tipping from flat will land the top of the anchor pretty close to the hole and starting on top of a 2x4 to lift that edge will get you even closer. It's still some grunt work and banging to get them lined up in the real world, but for typical 8-9' walls it's easy enough without getting cranes or Lulls involved.
A bigger issue for me has been having anchors line up right where a stud needs to be!
Andy,
Looks like I’ll be embedding several Simpson HDU hold downs, which means those anchors will need to stick up ~4” to also account for the u-washer in the hold-down.
Think it will be a struggle to lift the walls over these anchors, even with the 2x4 underneath?
Adam
I've done it with the big HDUs, but honestly can't remember if it was that much harder than going over the top of a typical wall anchor. I think it was just about the same level of hassle since I was working solo, but then again these walls weren't very tall or particularly long. 8-9' walls can be pushed around a bit manually with enough leverage.
I used Titen HD anchors instead of embedded anchors on my workshop build. Without anything to keep the plate from moving around initially (nothing to position/pin the wall in place while tipping up), the gasket ripped off the staples on the first wall. On the other walls, we got smart and dropped some short rebar pins in a few of the holes to limit the motion.
Anything to limit wall motion during tip-up will make things easier with the gasket, that's for sure.
I had the same thought about screw in anchors as well. For a big enough wall, not having to navigate anchors that are already there has to be a big win.
I think it's also important to reflect on what the purpose of the sill seal is in the first place. People fool themselves into thinking that it's an air barrier. That may be the case if you are using the Conservation Technologies product, but not when you're using the foam stuff as there's too much to go wrong (seams, tears, surface irregularities, etc.). The foam stuff does make for a good capillary break, however, which is why I've used it and then followed up with other means of air sealing. But, in this lift and set situation, I think I'd be focused on providing a capillary break if my plan was to air seal the junction in a robust manner anyway.
If the foundation surface is reasonably smooth, I'd consider robust flashing tape adhered to the bottom of the plate to be a decent alternative to stapled foam sill seal. (Alternatively, the foundation could receive the material instead of the wall, but it's often harder to get things to stick to concrete than wood.)
Patrick,
I agree. I'd much rather air-seal on whichever side of the wall was the primary air barrier, and just include an effective capillary break under the sill-plate.
Patrick, is that to say that the Conservation Technology product is not actually effective at providing a capillary break? I wouldn’t need it for air-sealing purposes, since I’m also planning to air-seal at the exterior-side, and as for a vapor barrier (which I do need at the sill-plate since I am pouring a monolithic footer/stem wall) I can extend the sub-slab poly over the stem wall.
Sorry for the confusion. No, I meant that in addition to being a capillary break, it is also a reliable air seal, unlike the normal foam. Note that I haven't personally used their sill gasket, but have read positive comments about it here. The products of theirs I have used (door seal material) are high quality and thoughtfully designed.
Gotcha thanks. And your point about not relying on it as an air-barrier is well taken.
Yes, the screw in anchors might be an option, but my engineer would like to add rebar reinforcement for those anchors since the pull-out strength is not equivalent. Perhaps it’s still worth the extra cost
You should suggest to your engineer using epoxy anchors. Epoxy anchors can have similar pullout strengths to embedded anchor bolts, but they can be installed in the field in holes you can drill wherever you want them. Just keep in mind that hole prep is critical when using epoxy anchors if you want to achieve rated performance.
Bill
AdamPNW,
The problem with either screw or epoxy anchors when you are lifting complete walls (not just setting plates), is they don't provide the anchoring you need right away when the walls are lifted into place.