# We are stumped by hairline cracks in drywall



## big builder (Feb 26, 2008)

Hello All.

I am a professional builder.

Having build many new homes and cottages we are faced with a problem.

We use a very experienced drywaller.

On two of our last projects we have been plaqued with hairline cracks in the drywall and we cannot figure out why.

First project-

renovation
drywall cracked immediately after ceiling paint.
cracked on the original section of house not new addition.
ceiling was strapped on 12" centers
long cracks in the main areas...6 to 8' long.
building was heated and dry ( electric heat)


Second project

- New build
- Truss roof
- strapped 16" oc. Strapping was screwed up
- electric construction heat.
- Ceiling hairline cracked shortely after ceiling paint.
- Crackes were cut out and repaired.
- Just got a call from Owner that 6 or 8 cracks have re appeared.
- Went to look,,, house is at 32 % humidity which isn't too bad.


We are all stumped. Drywaller is stumped. I have had to cut out and repair and paint two full ceilings now and it getting expensive.

It looks like I will be re doing another full ceiling as well.

Drywaller has been fixing drywall no charge but I have bee paying for the painting.

To be honest we don't know really what to do or what is causing it.

Funny thing is it doesn't happen on most of the builds .

Drywaller says he has never seen it before.

Looking for discussion on this issue to try and get to the bottom of it

These two projects do not have much in common other then the drywaller, and supplier.

One was a winter build and one was a summer build.


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## mikeswoods (Oct 11, 2008)

A better description of the drywallers technique would help---paper or mesh tape?

Type of mud?

Screwing pattern?

Could be truss heave also---


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## hdavis (Feb 14, 2012)

Crack locations - flats, tapers, corners, all of the above?


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## big builder (Feb 26, 2008)

Hi,

I will do my best. I am not a drywaller so bear with me.

This is what I know.

- 1/2 cgc.
- Prefill if necessary with 90
- coated with premixed mud in box cgc
- cgc paper tape.
- not sure on screw pattern but I know he prides him self in using lots of screws.

- I am not sure on the truss heave......my thoughts is this displays itself at the intersection of truss and top plate usually? Our problems is showing on the flats.


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## hdavis (Feb 14, 2012)

Pictures would be good. That could happen if the strapping was too dry. It will pick up a lot of moisture once paint is put on.


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## Sir Mixalot (Jan 6, 2008)

Wet lumber when the home was constructed and is now drying out or truss uplift come to mind.


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## big builder (Feb 26, 2008)

Hi Guys,

I really appreciate all the brainstorming.

The current problem ( new home) was a summer build. Very little rain before the roof was one. Lumber is what it is. Bought from our local building center. 

I have never heard of too dry strapping before.

There are now 5 or 6 cracks in the current problem home. cracks vary from 2 feet to six feet long.


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## big builder (Feb 26, 2008)

Has anyone used resilient channel instead of strapping on an entire house before?

Is it a lot better?


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## We Fix Houses (Aug 15, 2007)

I wonder if Lite dw compund was used in the last finishing coats ?

Lite is far more fragile than All Purpose mud. This in combination with high MC in the framing may have did it ?


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## We Fix Houses (Aug 15, 2007)

Big builder - where are you located ?

You say strapping ? Was the strapping kiln died --- with the lumber stamped ? It could have been #2 or #3 grade not dried or stamped. This can be a problem ?


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## hdavis (Feb 14, 2012)

Cracks at the edges or out in the middle of the ceiling?

Normally I'd think things were drying out or truss uplift, as mentioned. In this case, I got the impression that the cracks were along the tapers out in the ceiling, not edges.

The usual problem to see with strapping moisture content is too high of a content. In a reno where the ceiling is strapped, the strapping ends at the upper angle, and this is where you can get cracks when it shrinks.

If the trapping is too dry, it expands when it takes up moisture. Generally, the upper angles aren't cracked, but you can get some on the tapers.


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## big builder (Feb 26, 2008)

Hello,

I will try and answer these questions.

These are all flat ceilings. No slopes or cathedrals. Has a tray ceiling but that area seems fine.

Yes is the graded and stamped SPF for framing. I am not sure if the strapping is graded and stamped but I highly doubt it.

We are location in Central Ontario , Canada.

Cracks are mostly in the middle areas, some extend from wall out into the main ceilings.

he uses the CGC lite. I discussed this with him and he drywallers says he has been using that for many many years and has never had problems before.


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## We Fix Houses (Aug 15, 2007)

In the future go to APC would be a good start.


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## KAP (Feb 19, 2011)

Try 5/8th's instead of 1/2" on ceiling...


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## hdavis (Feb 14, 2012)

big builder said:


> Has anyone used resilient channel instead of strapping on an entire house before?
> 
> Is it a lot better?


I know one guy on here has. My recollection is he really liked it.


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## big builder (Feb 26, 2008)

Again thanks everyone.

I don't think 5/8's drywall would have an affect on our problem.

Can someone clarify what APC is?

Thank you


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## Sir Mixalot (Jan 6, 2008)

big builder said:


> Has anyone used resilient channel instead of strapping on an entire house before?
> 
> Is it a lot better?


Yes, I like it better than wood.



big builder said:


> Can someone clarify what APC is?
> 
> Thank you


All Purpose Compound I beleive. :thumbsup:


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## Warren (Feb 19, 2005)

All Purpose Compound.

Was the 1/2" used on 24" centers?. There tends to be a lot more movement in ceilings than there is on walls.


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## big builder (Feb 26, 2008)

Hi Everyone.

Sorry about missing the APC thing ...

We will definitely try that.

Trusses are on 24" o.c but then strapped to 16" o.c with 1 by 4 strapping.

I guess it is definitely worth a try using the steel channel and regular mud.

We are framing a few right now so I want to not make the same mistakes again.


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## Metro M & L (Jun 3, 2009)

Rushing to paint over incompletely dry mud? Did you have a tight schedule on these builds that your crew was racing to meet?

I think I would try retaping the cracks rather than tearing it all down and starting over.


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## blacktop (Oct 28, 2012)

Any steel beams involved on those two jobs?


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## blacktop (Oct 28, 2012)

big builder said:


> he uses the CGC lite. .


I would never apply tape with L/W! No glue.


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## Big Shoe (Jun 16, 2008)

Was the tape not bonding? Tape issue?

We had some problems with a brand of paper tape. I don't think the mud was adhering to it. Like it was not porous enough. Same type of things were happening. Several homes were affected.

Switched to another brand and problems went away.


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## big builder (Feb 26, 2008)

Hello,

Yes there are steel beams in the basement. But that is how we build all of our homes. This does not happen all the time. Steel beams only support the floor not the roof.


Yes we do prime shortly after the sanding is done.....but we have assumed if it was sanded it would be dry .... should the drywall be left to sit awhile after its sanded?

Also on one house ( still have to address the cracks) we noticed cracks immediately after the ceilings were painted. The drywaller came back cut out the tape ( which he said was well bonded) and retaped, sanded and repainted. Now I cant be sure if the new cracks are in the same places as the old. We have a site meeting there later this week and I am sure he will remember if he has done them before.

He specifies that we only supply CGC board, mud and tape and course thread screws.


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## big builder (Feb 26, 2008)

I will try and take pictures when I go over to meet Owner again and discuss. I will see if they show up.


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## big builder (Feb 26, 2008)

Sorry one last comment.

One build has steel basement beams.

Other build was a reno and it was Engineered slab. That one cracked in the original portion with the original strapping...which was on 12" centers.

I am sort of leaning towards on our current projects.

- resilient channel
- regular weight mud ( APC)
- 1 week left between final sanding and priming
- 1 week left between priming and painting

Can't really think of much else to change in our approach.


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## We Fix Houses (Aug 15, 2007)

Did you heat the place with propane after dried in and during dw ?

Propane gives off a heck of a lot of moisture.


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## elliot (Jan 24, 2009)

*hair line cracks*

Hi, Ever since hurricane sandy notice many houses with hair line cracks along the flats both up and downstairs.If you chip at the crack the crack does not go through to the tape. Me an several architecs feel it is due to wind sheer the houses bounce and its just enough to pop the compound in the center of the seams.Only noticed on clgs and only on flats.Sometimes when they frame with the tgi beams their also seems to be a lot more bounce because the span is greater


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## blacktop (Oct 28, 2012)

big builder said:


> - resilient channel
> - regular weight mud ( APC)
> - 1 week left between final sanding and priming
> - 1 week left between priming and painting
> - Tape all seams and butts with hot mud and paper


.....


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## big builder (Feb 26, 2008)

Hi,

Yes when we looked at the tape it is not cracked through the tape just the compound on top of the tape but enough so that it's clearly visible standing on the floor.

We only use electric construction heat. We usually have two or three of the 5000w electric heaters going in each house .


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## D.E.P.S. (Aug 3, 2013)

Big Shoe said:


> Was the tape not bonding? Tape issue?
> 
> We had some problems with a brand of paper tape. I don't think the mud was adhering to it. Like it was not porous enough. Same type of things were happening. Several homes were affected.
> 
> Switched to another brand and problems went away.



I'm wondering if we might run into the same tape. I bought a box of the stuff a while back and it had almost a glossy sheen on the paper. Even the green top USG didn't seem to lock on. The mud seemed like it wanted to roll off the paper. I used about a 1/2 roll of the stuff and returned the rest. The counter guy at my supplier thought I was nuts and started laughing. (_he is a friend_) I went out to my truck and got a partial roll of the older tape he sold me and I showed him the difference. After seeing and feeling the difference between the two, he immediately went back into the warehouse and found some older stock for me.


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## D.E.P.S. (Aug 3, 2013)

The most common reasons that I know of for cracking:

1. Building movement....._but you should see screw pops and corner cracks along with the field cracking_.

2. Mud applied to thick...._probably not in your case because you have a experienced finisher._

_3._ Mud drying too fast...._ usually from excessive heat or very low humidty._

_4. _Primer with high water content...... _this creates almost a micro thin shell on the dried compound surface that is fragile and brittle. I have ran into this 3-4 times. The cracks would develope mostly in the" butts" and "flat"s areas. Vibration just from foot traffic was enough to crack it. The problem would show itself within a couple weeks._

I hope you find what is causing it.


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## D.E.P.S. (Aug 3, 2013)

I forgot to add that painting over compound with high moisture content can cause the same cracking as I stated in item 4 in my last post. The moisture locked in from the primer coat will undergo pressure changes and need some place to go. It might take quite a few cycles of temp changes, but it will eventually bust the paint and a leave a very fine cracking on the surface of the compound.


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## big builder (Feb 26, 2008)

D.E.P.S. said:


> I forgot to add that painting over compound with high moisture content can cause the same cracking as I stated in item 4 in my last post. The moisture locked in from the primer coat will undergo pressure changes and need some place to go. It might take quite a few cycles of temp changes, but it will eventually bust the paint and a leave a very fine cracking on the surface of the compound.


These are all very valid points.

Our drywaller has been very good about this problem and has not abandoned us even though it has cost him money as well.

He does insist we use Bengamin Moore or Para thick hide primer only. He insists that it is the best quality and much better than other " builder grades" I always use this. We spray and then back roll.

He also says this primer is better for him to see any areas to touch up if necessary.

This thought of the high moisture ( either in the mud or in the paint) seems like a strong possibility.

Thanks again everyone.!


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## iDAHOchris (Feb 11, 2012)

It kinda sounds like a delayed shrinkage going on. From start of taping to painting,, how many days? Some builders in my area only allow 3 days to tape and texture a house which I feel is recipe for disaster, thats why we dont do spec homes anymore. If the taping is done too fast the joints havnt had enough time to completely cure, then it gets hosed down with paint and dries again..... cracks


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## Sir Mixalot (Jan 6, 2008)

Was the drywall hung parallel or perpendicular to the strapping?


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## big builder (Feb 26, 2008)

well I have never thought we were rushing any thing. I mean we don't waste any time from when the sanding is done until when the priming starts but isn't that the way all builders do it?

Funny thing is on the one we are having problems with now we have already cut out and fixed the cracks once ( a couple of weeks after the ceiling was finished) now its about 4 months since delivery and the Owner called to have me look at it.

First thing I thought was the house was too dry . He asked for no humidifier on the furnace. But the house read 31% on the evolution t stat we installed. Which is ok. I prefer about 35 % but it is within spec.


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## big builder (Feb 26, 2008)

Sir Mixalot said:


> Was the drywall hung parallel or perpendicular to the strapping?


Isnt it always perpendicular?


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## Sir Mixalot (Jan 6, 2008)

big builder said:


> Isnt it always perpendicular?


Yes. :thumbup: 
Just had to ask, so no stone would be left unturned.


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## icerock drywall (Aug 16, 2012)

if you push on the crack dose the drywall move?


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## ubcguy89 (Mar 23, 2013)

I'm a commercial guy, and when I do residential side work, I always glue my ceilings. I don't glue walls or lids on Chicago grid. But on wood I glue the ceilings. I also use 5/8 on ceilings. My finishers tape and coat with all purpose. They also always use paper tape. Make sure the joints are tight, and if they need to prefill, maybe go with durabond 120 or 210


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## sandshooter (Dec 30, 2012)

ubcguy89 said:


> I'm a commercial guy, and when I do residential side work, I always glue my ceilings. I don't glue walls or lids on Chicago grid. But on wood I glue the ceilings. I also use 5/8 on ceilings. My finishers tape and coat with all purpose. They also always use paper tape. Make sure the joints are tight, and if they need to prefill, maybe go with durabond 120 or 210


(x2)


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## pathway (Jan 9, 2014)

ubcguy89 said:


> I'm a commercial guy, and when I do residential side work, I always glue my ceilings. I don't glue walls or lids on Chicago grid. But on wood I glue the ceilings. I also use 5/8 on ceilings. My finishers tape and coat with all purpose. They also always use paper tape. Make sure the joints are tight, and if they need to prefill, maybe go with durabond 120 or 210


Curious if you glue ceilings with vapour barrier as well? I personally dont see any advantage but perhaps I'm missing something.


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## ubcguy89 (Mar 23, 2013)

pathway said:


> Curious if you glue ceilings with vapour barrier as well? I personally dont see any advantage but perhaps I'm missing something.


Staple itch to inside of the joists/truss


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## endo_alley (Apr 9, 2013)

You say the job was heated. Was it heated with temporary heat? If you put a lot of heat in one spot, the above ceiling will get quite warm and expand. Turn off the heater and the drywall will almost always crack as it contracts.


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## Stoneyard (Mar 30, 2014)

Assuming that the drywall was installed correctly, it breaks on a truss, screwed correctly, etc,etc. From what I am reading it sounds like truss deflection. Expansion/contraction, snow loads, high winds will cause this. Do you have rat runs and troughs installed on the top of the bottom cord of the truss? Running a 2x6 flat with 3 nails per truss from gable end to gable end with another 2x6 turned up on edge nailed to the first and thus creating an "L" shaped trough. This will go directly above the expanse of the room in question. Tying it all the way through to the exterior walls and onto the gable truss is important as well. Also make sure the truss's are nailed down to the interior load bearing walls directly affecting this room. If your 2x6's are not long enough to span from gable end to gable end make sure you put a 2x6 splice on top of the 2x6 run(flat one) which spans the joint for at least 2.5 feet in each direction so your splice go's past the next truss. I hope this makes sense since its hard to describe. I have also seen framers use one by four for their rat runs and troughs and this material is not strong enough to do the job. It has to be 2x6. Hope this helps.


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