How to tie new wall into parallel joists

[Tom M King]

Hi Tom, just a typical drywall ceiling with stipled compound. I had to fix a small section of the same type of ceiling in our kitchen following a leak in an upstairs shower drain. I want to avoid having to patch 20 ft if ceiling if I can.

Cut the slot for the wall through the drywall, leaving 1/4" on each side, for a total width of 4". Cut lengths of 2x6 that you can get in there, that will hit the joist on one side, and cross the slot as much as it can on top of the sheetrock on the other side.

Buy some tubes of Powergrab, and some 8x construction adhesive. Cut enough of those lengths of 2x6, so you can put one every foot, or such. Put the 8x on the end that's going to be jambed against a joist, and the Powergrab on the flat face that will bed down on the sheetrock. Alternate each piece to jamb against the opposite joist. Slide them back, and forth a little bit, pushing on them to get the construction adhesive to give as much surface area as possible.

Let that set up for a day, or two, and screw the top plate to those blocks. Cut each stud a little long, and hold it in place on top of one side of the sole plate, and beside the top plate. Use a sharp pencil to mark the length perfectly, for a slide fit. You want the fit of each stud to be a slide fit, that touches both ends, but doesn't push the top plate up any.

If you can also glue a few brackets of plywood against the blocks, and the joists, it would make it some stronger, but that should be okay for a partition wall.

Gather all your worn out socks, washcloths, and any such to use as wet rags to wipe away any Powergrab that gets squeezed out where the top plate needs to go, while it's still wet.

Mark the length of each stud where it goes, before you start cutting them. Start with the longest. If one ends up a hair short, it can be used at one of the shorter locations.

[Brian Tymchak]

Cut the slot for the wall through the drywall, leaving 1/4" on each side, for a total width of 4". Cut lengths of 2x6 that you can get in there, that will hit the joist on one side, and cross the slot as much as it can on top of the sheetrock on the other side.

Buy some tubes of Powergrab, and some 8x construction adhesive. Cut enough of those lengths of 2x6, so you can put one every foot, or such. Put the 8x on the end that's going to be jambed against a joist, and the Powergrab on the flat face that will bed down on the sheetrock. Alternate each piece to jamb against the opposite joist. Slide them back, and forth a little bit, pushing on them to get the construction adhesive to give as much surface area as possible.

Let that set up for a day, or two, and screw the top plate to those blocks. Cut each stud a little long, and hold it in place on top of one side of the sole plate, and beside the top plate. Use a sharp pencil to mark the length perfectly, for a slide fit. You want the fit of each stud to be a slide fit, that touches both ends, but doesn't push the top plate up any.

If you can also glue a few brackets of plywood against the blocks, and the joists, it would make it some stronger, but that should be okay for a partition wall.

Gather all your worn out socks, washcloths, and any such to use as wet rags to wipe away any Powergrab that gets squeezed out where the top plate needs to go, while it's still wet.

Mark the length of each stud where it goes, before you start cutting them. Start with the longest. If one ends up a hair short, it can be used at one of the shorter locations.

Tom, thanks for your post. Very informative. I really appreciate that. I never considered using construction adhesive to attach the blocking. That sounds a lot easier than trying wrangle some kind of power driver in that slot.

[Tom M King]

Make sure you get fresh Powergrab. It gets stiffer as it ages even unopened. Warm both types up just before you use it, and it will squish easier.

When you screw the top plate to the blocks, don’t try to pull down any blocks that are up more than it’s neighbor, or you will have waves in the ceiling.

Sorry for any misspelling, or bad grammar. Using phone, and reallly tired, including eyes.

[John Olier]

Cut your top plate to go just to the ceiling then toggle bolt the top plate to the ceiling in two places. It wont move after you sheetrock it.

[Ron Selzer]

Hi Ron, both walls have an anchor on both ends.

So your suggestion is to use the ceiling itself to anchor the top of the wall. Interesting. I would not have thought that would be strong enough but your point of being anchored on 2 ends - maybe I'm be too worried about that. I didn't mention that there will be a door in each of these walls, not that that will add any load. And Jim did raise a good point about the load on the walls. I had not considered that. I'm thinking that load will very minimal, but that doesn't mean the next owner might not hang something heavy. Hmm, things to consider.


Thanks!

the 2x4 you put above the ceiling between the joists will anchor the wall. the screw thru the ceiling is to hold the 2x4 in place so you can screw the top plate to it

[Bruce Wrenn]

Cut your top plate to go just to the ceiling then toggle bolt the top plate to the ceiling in two places. It wont move after you sheetrock it.

Steel studs and track is the way to go, unless there are loads to be supported on the sides of the walls. Molly bolts in top track, thru sheet rock. Drill holes on track before trying to mount it to ceiling. Bottom track can be drilled and screwed to the floor, or shot down with powder activated gun. Drilled and screwed makes a lot less mess to repair if wall is removed

[Jerome Stanek]

Steel studs and track is the way to go, unless there are loads to be supported on the sides of the walls. Molly bolts in top track, thru sheet rock. Drill holes on track before trying to mount it to ceiling. Bottom track can be drilled and screwed to the floor, or shot down with powder activated gun. Drilled and screwed makes a lot less mess to repair if wall is removed

This is how we installed office walls in commercial places.

[Bill St Amant]

for a dust wall without electrical work you might use a continuous piece of foam [armaflex for instanace] over the top plate then wedge the wall in. It would help if the walls had returns so they were more like free standing objects. if there is no door and not much hanging shelves, then it won't go anywhere.

[Lee Schierer]

Since you are able to cut a hole in the ceiling you should be able to insert one of these up into the joist space. Once there you can crank it tight and use the box as your anchor point. It will slide along the length of the shaft. To match the location you need for your wall.
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[Jim Becker]

That looks like a new work ceiling box, Lee, but I could be mistaken. If so, it may be hard to install through a 4" hole.

[Brian Tymchak]

Steel studs and track is the way to go, unless there are loads to be supported on the sides of the walls. Molly bolts in top track, thru sheet rock. Drill holes on track before trying to mount it to ceiling. Bottom track can be drilled and screwed to the floor, or shot down with powder activated gun. Drilled and screwed makes a lot less mess to repair if wall is removed

for a dust wall without electrical work you might use a continuous piece of foam [armaflex for instanace] over the top plate then wedge the wall in. It would help if the walls had returns so they were more like free standing objects. if there is no door and not much hanging shelves, then it won't go anywhere.

Had not considered steel stud construction. I've not worked with it before though, and I'm leaning towards a wood stud wall to avoid consideration of side loading in the future.

I will be running electric in these walls, repositioning switches, adding circuits, redoing some lighting if it can be done without damaging the ceilings. Hopefully I can add a 220v circuit or 2 to allow future tool enhacements.

[Brian Tymchak]

Since you are able to cut a hole in the ceiling you should be able to insert one of these up into the joist space. Once there you can crank it tight and use the box as your anchor point. It will slide along the length of the shaft. To match the location you need for your wall.
Capture.JPG

That looks like a new work ceiling box, Lee, but I could be mistaken. If so, it may be hard to install through a 4" hole.

Lee, I had a similar thought after Bill commented about them. I initially balked at the cost, but in the end it might be worth spending a $100-$125 to solve the problem. I think I googled up the same mount you posted, from Lowes site. I have the same question as Jim raises. The site says the box is only 1.5" deep so I think I can slide it thru a slot and rotate into place. It also appears the box can be removed and replaced with a wood block. Hopefully I can get to Lowes/HD this weekend to check them out. ....And now that I think about it, if I replace the box with wood, I would probably remove the box prior to installing in the ceiling, so there shouldn't be any issue with clearance.

After some thought about Jim's previous comment about what load I might put on the wall, I leaning to wanting to anchor the top plate as solid as possible to avoid that consideration in the future. Given all my assumptions fall my way, it feels like these mounts might be the best option short of getting full sized cross blocks screwed into joists.

[Brian Tymchak]

Want to extend my appreciation for everyone that responded on the thread. Your replies offered a lot options and details that I had not considered.

Thank you!

[Jim Becker]

How will you fasten the legs of that assembly to the joists above the ceiling with no access? You may be able to get the same general effect by just putting a piece of narrow plywood up through a small hole in the ceiling at intervals, screwing it through the drywall/ceiling covering to hold it in place and then screwing up through the top plate into the plywood which makes a "clamp" on both sides of the existing ceiling. Cheap, too.

[Lee Schierer]

Lee, I had a similar thought after Bill commented about them. I initially balked at the cost, but in the end it might be worth spending a $100-$125 to solve the problem. I think I googled up the same mount you posted, from Lowes site. I have the same question as Jim raises. The site says the box is only 1.5" deep so I think I can slide it thru a slot and rotate into place. It also appears the box can be removed and replaced with a wood block. Hopefully I can get to Lowes/HD this weekend to check them out. ....And now that I think about it, if I replace the box with wood, I would probably remove the box prior to installing in the ceiling, so there shouldn't be any issue with clearance.

After some thought about Jim's previous comment about what load I might put on the wall, I leaning to wanting to anchor the top plate as solid as possible to avoid that consideration in the future. Given all my assumptions fall my way, it feels like these mounts might be the best option short of getting full sized cross blocks screwed into joists.

I suspect that the tightening tube is hollow, which would allow you to drill and tap it so you could attach the top plate with a screw to to tube. If it is tightened properly it should give you pretty good lateral stability. You could also put a u-bolt over it that would come down through the top plate.