hikerguy

Joint compound that's flexible....

Is there such a thing as "flexible" joint compound? The reason I ask is we have a couple of walkways that had cracks about 12" long (maybe 1/8" wide) that I repaired about 4 months ago. The cracks have since come back. I have been told that we live in an area where there's "expansive soil", so the ground is continually expanding and contracting (we live in Durham, NC).

Is there any way to repair cracks like this so they don't keep coming back (given the soil condition we have to deal with)?

Thanks,

Andy

stickshift

I'm a little confused - joint compound is for drywall joints but it sounds like you might be talking about some kind of sidewalk-like area

marksr

Ya, with j/c, I think drywall...... but it does sound like you mean a concrete patch.

Caulking is about the only type of flexible material. As you did [or should have] with your original repair - you need to clean out the crack, make it wide enough to force the caulk down a little way so it will have plenty of area to bond to...... but caulk will only stretch so far

chandler

You may want to upgrade to butyl rubber caulk in those cracks. It is impervious to weather and will flex with the movement to an extent. But clean them thoroughly as Marksr said, then force it down using a small cut on the tip.
Yeah, the title had my interest piqued. Joint Compound vs. concrete....which would win?

hikerguy

Guess that was confusing. I am talking about repairing a crack in our drywall. We live in North Carolina (the land of clay soil) and I think what's happening is when the clay gets wet, it's expanding, and when it dries, it contracts. I think this is what's causing us headaches. The two I mention are the worst (as there literally is a gap of ~1/8"). In other areas of the house, we see hairline cracks.

I just wanted to know if there's any material we could fill these cracks with that would flex, but that could also be painted.

Thanks,

Andy

chandler

Elastomeric caulk....Big Stretch comes to mind. Although you have foundation problems that won't go away, and the caulk won't fix it.

marksr

It sounds like this is going to be an ongoing issue

Depending on the crack and the movement, caulking might be able to keep the crack sealed but it might not make the crack disappear. Joint compound and tape would do a better job of hiding the crack but the crack might reappear at the edge of the tape.

equinox

You didn't mention where the cracks are occurring. That can also make a difference in regards to any other issues around how the wall board was installed. Sometimes if we guess what causes things to happen we can easily ignore other common reasons in the process. Cracks around doorway headers if the boards did not overlapp the header joints, and even on ceilings if the boards were not staggered can also be an issue in any home. How have you been repairing the cracks? Only with drywall compound? Adding additional strength to the crack using a mesh tape may also help in holding it all together. Is your house sitting on foundation walls, or on a pretensioned cable pad? If on a pad I would also be concerned about what else could be happening under the floor surface if the drywall issue is confirmed to be a soil based movement issue. Are there any preventative options also to reduce the movement. Texas homes have the same kind of issues due to the Texas clay, and for example there it is recommended to keep all soil around the foundation watered during the summer months to reduce shrinking by helping to maintain a constant moisture level under the pad.

coops28

How did you fix the cracks? Please be specific. Thanks.

hikerguy

The cracks are occurring over the walkway into the kitchen and living room. I used joint compound from Home Depot to fill the crack (I didn't use any mesh tape). I just put enough in to fill the gaps, smoothed it out, then sanded once it dried. The crack itself is no more than 1/8 wide, so would mesh tape help in this case?

Here's the joint compound I used:

Sheetrock All-Purpose 5-Gallon Pre-Mixed Joint Compound - 380501 at The Home Depot

The house sits on cinder blocks (the crawl space is approx 3' high. I can squat and walk around pretty easily, and I'm 5' 7").

Thanks,

Andy

coops28

You need to tape the crack. I don't recommend mesh tape because it will crack on you. Use paper tape with the all purpose mud. You need to tape or it will keep cracking no matter if your house moves or not.

hikerguy

Coops,

Are you saying I should tape it, even with an 1/8 in crack? It makes
that much of a difference?

Thanks,

Andy

equinox

While we don't all agree on issues around mesh verses paper tape, I think we are agreeing that you should tape the cracks as part of the repair.

marksr

Yes, any untaped joint or crack filled with regular joint compound will crack again. You might get by without tape if you use a setting compound but it's better to play it safe and tape. It will take a couple of coats of mud over the tape [feathering it out further each time] to make the tape disappear.

hikerguy

Great. I appreciate the info. I'll use some tape this time and see if it comes back in a few months. I'll re-post either way.

Thanks,

Andy