joint compound on densshield?

[Jason_Morrison]

i have a guy here doing the finish work on my drywall. he asked if i wanted corner bead on the corner where the densshield for my shower meets the drywall. i said yes but i didn't think to specify that i didn't want joint compound on the denshield side of the corner. Here is how he finished it out today while i was gone.

so now i'm wondering if this is wrong. I was going to use a topical membrane over the screws and seams. So i guess i can do that overtop of the joint compound too... i am trying to decide if i should go try scrape it off now before it completely dries.

[PC7060]

I’d scrap it back. Now, because it won’t get any easier later!

I’m sure he thought he was doing you a favor. Some of my biggest headaches have started that way.

[Jason_Morrison]

i took your advice. i was able to scrape most of it off with a putty knife and then used a sponge to wet the stuff that had already dried so that it could also be scraped. after that i scrubbed it all down with the sponge to life most of the joint compound residue.

[Kman]

I think you did the right thing. You really don't want joint compound anywhere within the interior of the shower.

[Jason_Morrison]

thanks, so now do i just use my 6" fiberglass and the waterproofing membrane on all the joints or do i need to do a layer of thinset + mesh tape first?

[Jason_Morrison]

looking for some advice on building my shower curb and pan. I'm planning to wrap the pan and curb with kerdi or some other sheet membrane. sealing all transitions with a topical membrane and fiberglass mesh.

I want to pour a solid curb from concrete. I built some forms today. I'm wondering if i should try to anchor the curb to the floor with some type of anchors? I could drill some holes in the subfloor and install some J bolts. Or should i do a skim coat of thinset to the plywood and then pour concrete on top of that while its still curing?

similarly, do i want to try to lock the curb to the pan? should i run some rebar or other metal out the side of the curb so that the shower pan can be packed in around those anchors?

when i do the shower pan, should i lay down a sheet of roofing felt first or would it be better to skim coat that with thinset to get some bond between the pan and floor?

[John Bridge]

Hi Jason,

Anchoring the curb is not a bad idea.

Don't worry about anchoring it to anything else. And use the tar paper between the subfloor and shower floor mortar.

You mention using some sort of membrane for the transitions. I would use the Kerdi membrane.

[Jason_Morrison]

Thanks John.

I'd forgotten that i was going to do roofing felt and then staple down some self-firring lathe to tie the pan to the subfloor.

for the curb i'll do roofing felt with J bolts next to each floor joist.

FYI, I built the forms with 1/8" drop over the 3.5" wide curb. I'm going to set a solid piece of quartz on top of this curb.

I will probably use kerdi, i can get some for the same price on amazon as the alternative membrane that they sell at Menards.

[Carbidetooth]

A few screws driven into subfloor and left sticking up into forms would be more that adequate to limit lateral movement. If it's reinforcement you're after, cut a strip of the expanded lath and tie to protruding screws. Stainless would be ideal, but hot dipped would also work.

Depending on the diameter of j bolt you have in mind, you could potentially weaken the overall structure of curb.

FWIW, it's all way beyond what's necessary for the task at hand.

[Jason_Morrison]

well hopefully i didn't weaken it. i might have gone overboard...

[cx]

I hate to be the one to say it, Jason, but a stack of three 2x4s woulda been a whole lot easier. And less likely to crack.

My opinion; worth price charged.

[Jason_Morrison]

i was going to do 2x4's but it seems many people consider that inferior due to the movement from wood.

this really wasn't hard to do, took a couple of hours. this is my own bathroom and probably the only shower i'll build, atleast in the next 10 years so I dont mind a couple hours extra work over the 2x4's.

if i develop hairline cracks, it shouldn't matter on a kerdi wrapped shower right?

[Carbidetooth]

Wood moves in response to moisture. If done correctly, it will never see moisture beyond ambient humidity.

Did you coat your forms with some sort of release agent? Strength contributed from rebar in various structures is primarily from the gridwork created by tied network. You effectively weakened by sheer size of reinforcing. It wouldn't surprise me to see cracking aligned with rebar.

Fiber in your concrete mix would have been more than adequate. I and many others use Kerdi Board for curbs. Has the monolithic end result that you're after, without down sides.


Theoretically, 28 days for your concrete to reach 80% cure. I'd pull your forms after a day or two, cover with plastic and let cure before moving ahead with your Kerdi. Kerdi is not designed to be an isolation membrane, which is what you'd be asking it to do.

[cx]

What Peter said, except I would also anticipate some lateral cracking where you have those large eye bolts.

And you really want to get that concrete covered in poly as soon as possible. You have a great deal of surface area compared to the volume of your pour and that will quickly result in the surface area drying out and ceasing or slowing hydration. It will also result in more shrinking and cracking potential.

In the best of all worlds that concrete would prefer to be submerged in water once it has reached about 500psi compressive strength, which it has already likely done. Covering completely with polyethylene is the second best option.

I'd wanna pull those forms as soon as possible and get it covered. Covering it before you remove the forms would be a good idea if you actually plan to wait a couple days.

My opinion; worth price charged.

[Jason_Morrison]

so would you guys say that if it doesn't crack in the first couple of weeks I'll be ok?

I actually thought i was over-building this thing
is the concern with my method just the eyebolts and rebar? if i'd have done lathe, it wouldn't be a concern?

what is the method for people that use bricks and mortar? do you pin it to the floor or just rely on the mortar to stick?