It appears humidity is getting in there somehow. Best resolved by having the original builder involved in making you whole, either by correcting the source of the problem and doing the repairs without you paying any more, or they pay for someone else to do it. Try hard to work something out amiably with the builder.

What do I look for to determine if it’s humidity? We are trying really hard, attorneys on both sides now. He’s making it hard considering we still have a punch list a mile long.

Sophia, funny you say that about improper venting because our architect’s inspection said the same prior to the ceiling happening. Again, plans not followed on venting measures.

"funny you say that about improper venting because our architect’s inspection said the same prior to the ceiling happening."

Thats your starting point then......................

Were the beams added after the drywall? Before? Do the end of each beam rest within the framing?

Too little information. What is the insulation in the ceilng? If its foam it doesn't need to be vented. If its fiberglass it must be vented at the ridge and the eaves.

The bucking is so great I would suspect a roof leak even if it didn't drip from the ceiling.

Are you able to look into the attic space above the ceiling? Or is the ceiling nailed to roof joists?

Have you had a knowledgeable and experienced person inspect the ceiling and roof framing?

Allison, added after drywall. Not sure if they rest within framing.

Jds, insulation is fiberglass. The builder and trim guy came to look and went in the attic and saw no leaks.

Virgil, yes, I can look at the space above in the attic. And yes, we had an independent inspection done a month ago and there was nothing in the report indicating a problem with the roof.

But y’all, surely this isn’t from the house settling? Or wood contracting?

I’m going to go up there and look. Am I just looking for signs of water intrusion?

Make sure you go after dark. Turn out the attic lights. Look for light from below. Where light can go, air can go. Warm moist attic air condenses against the cool interior air. You now have water.

Thats just one a one of the many many pitfalls of an inattentive builder and a cathedral ceiling. There are more.

I'm going to guess its either the ceiling paneling expanding from getting wet or the rafters shrinking from drying. The latter seems more likely at the moment.

Are the rafters 2x lumber? Might the lumber have been green or air dried. or stored outside?

Where is the project?

The two logical suspects are: 1) Moisture, and 2) Movement. An inspection in the attic area should be helpful.

Is there any signs of cracking or movement elsewhere in the house, particularly in the foundation or floor framing? Wall cracking and gaps?

Or is the issue singularly isolated in the ceiling area?

JDS, I’m in Columbia, SC. I know the wood was stored outside.

Virgil, I’m not sure about foundation cracking or framing. It is not isolated to that one area, that is just the worst. There are horizontal cracks along the walls and around the beams elsewhere in the den. We are also seeing cracks between the wood floor boards, with cupping.

The most obvious possibilities are: 1) excessive humidity in the house or attic and 2) the rafters had a high moisture content when installed, or a little of both.

"...Virgil, I’m not sure about foundation cracking or framing. It is not isolated to that one area, that is just the worst. There are horizontal cracks along the walls and around the beams elsewhere in the den. We are also seeing cracks between the wood floor boards, with cupping..."

Photos? From these comments, it sounds as if the problem(s) may not be limited to the attic/ceiling-roof framing...?

It would help to know the framing of the ceiling and roof and if the attic is conditioned and if has any ducts or mechanical equipment in it.

JDS, the attic is not conditioned. The upstairs HVAC unit is in there with the ducting.

And the cracks are only on the right exterior wall section. There are no weep holes. Another deviation. Not sure if that is a contributing factor.

64% humidity? Is that the humidity inside?

If so, there is your answer. This is way high and can make wood swell/warp.

I live in the South. Do you have a dehumidifier system installed on your HVAC? If you do, make sure the drains are clean, clear and working. If you don't, have dehumidifiers installed by a good HVAC company. Your humidity goal is 40%. As you can see from your thermostat, you are way too high. This will cause a problem. The cupping of the ceiling is the symptom and humidity is the cause.

I have painted wood plank ceilings. The planks will expand if the humidity is too high. It doesn't necessarily mean you have a roof leak. It's just too humid inside the home. When the planks are in a humid state they will expand, the pressure has to go somewhere. The decorative rafter is decorative and not structural. That's why it's moving when the force of the expanding boards moves.

You also mention other moisture problems. Has the crawl space been properly encapsulated with moisture barrier? What is the humidity level in the crawl/basement? Have you measured it? Is there a dehumidifier for this area? What is it's level? It should be at 40%.

Do you have proper exterior drain tile? Drain tile or French drains can become blocked or crushed during construction. They may need to be dug up and reinstalled. Are your gutters draining far enough away from the foundation? You may need extensions.

Water is the enemy. Humidity is the enemy. All of these conditions can be present with a good roof.

In conclusion, dehumidifiers, crawlspace encapsulation, drain tile operation, and gutter extension. I doubt it's the roof, but it won't hurt to look at it. Why am I so sure? Because I've owned, built and renovated a lot of homes. I understand the enemy, water. If it was the roof, you would have staining. This is excessive humidity and I bet it is coming from the crawlspace encapsulation being improperly installed and no dehumidifier for the crawl. You may also have drainage issues.

Given that there are now lawyers involved, you probably shouldn't post more about this situation. You may end up in Court and don't want any of your statements used against you.

After we had a flood in our basement our contractor brought in huge dehumidifiers; he wasnt happy until the humidity was at 40%.

I know next to nothing (ha ha) - all I can tell you is that if inside your house is 64% humidity I too think you've found your answer. I have wood floors and I know if my inside humidity gets over 50 I start to have issues with the floors - they will start to "hump up" similar to your ceiling planks. I keep my house at 40-45% and have no issues in that range.

Well at one point the humidity was over 80% inside a few weeks ago, so I thought we were doing good now. Crawlspace had major flooding/ standing water due to improper grading and called for water mitigation measures not followed. It has since been encapsulated with drains installed and a dehumidifier down there and is dry. I assumed we had a dehumidifier since the panel will read dehumidifying but I’m not sure.

Dry and proper humidity are two different elements. If you have working dehumidifiers in the crawl and the house, it will take a little while for them do their work. Two weeks would be a good point. We are outside of Atlanta, have had a very wet summer and our systems were at 43-45% this last week. As part of your home maintenance routine, you should check their operation monthly. Your HVAC guy will direct you on how to maintain the lines so they drain effectively. Ask him to show you. It's easy.

The other issue is high humidity will allow mold to grow. You have to get on top of this before this becomes an issue. It sounds like you are working on this.

We purchased a home last year that had a long standing roofing issue draining down one wall and into the crawl space. Once we got the leak resolved, the mold and mildew damage removed and repaired, our fabulous HVAC contractor installed dehumidifiers and an additional device called a GPS. It's mostly used in commercial settings and is not an ionizer. But, it scrubs the air and removes mold, mildew and allergens. (My allergies have mostly disappeared!) GPS System I recommend the GPS solution without reservation. Some HVAC people will recommend a black light. Those don't work because they can't kill unless the air is static. The high air flow won't allow them to do their job. Between the dehumidifiers and the GPS system, we have no worries about mold or mildew growth. Anything remaining behind that we missed is being rendered inert.

It sounds like you are starting to take the steps needed to deal with this. It's too bad you had to go through this when it's a simple matter to avoid in the first place by good drainage, humidity control and appropriate mechanicals.

Do I have this right?

So we do not have dehumidifiers inside the house, only in the crawlspace. We’ve got to get those installed, clearly.

sammy, yes you have it right. I spoke to our architect about ventilation in that space. We need to determine if it’s a truss system there, as per plans or if it’s stick framing. The builder did not install the gable end vents.

We have a forensic engineer coming out tomorrow.

Have your engineer also check the valley at the intersection of the two roof slopes, shown in the section above at the right end of the red rectangle, to ensure there's no water leakage from that point anywhere along that roof valley.

This block wall was supposed to be waterproofed. Builder said he did. We can’t check at this point to be sure. I’ve asked for an invoice showing it was done and he can’t produce it. Could the failure to waterproof be contributing to moisture issues?

How much has it rained since construction of the roof and ceiling installation?

Nothing crazy. I’d say quick showers at most twice a week.

Curious why the humidity should be an issue. Is this a new build problem? Here in Connecticut humidity is currently 56% and I believe it was in the 70s earlier in the week. I don’t have central air, so inside my house would be the same. My wood floors are just dandy and there no mold growing anywhere. Houses were built for hundreds of years all up and down the damp east coast before central air. It’s crazy that we now are building houses that just fall apart when things get a bit sweaty. What if there’s a power loss? Will every house without a generator just tip right over?

Older houses are a lot more air- leaky. Air flows around much more easily in an older home. Most newer construction tries to be as air-tight as possible. Plus I believe newer construction with cement as the foundation is going to add humidity to the air for awhile too - my new home ran high on humidity as the concrete continued to dry out for the first few months or so we were in there.

It's a combination of issues I think. I don't necessarily think every newer home is going to fall over in a brief power outage. :-) The original poster said this has been going on for over 2 months, and that they were well above 80% humidity for awhile. That's tropical rainforest level! Plus they had a flooded crawlspace and needed mold remediation on top of that. There are some serious water issues at play here.

Old homes were built with old growth lumber. Newer homes are built with wet lumber. The entire house needs to be drying out. Between the foundation, the wet lumber and the climate, it's a recipe for a swollen, damp house. Water is always the enemy, old or new.

I can't understand the foundation or the red arrows. As for vents crawl spaces should be sealed and not vented in humid climates. Attics should have eave and ridge vents rather than gable vents but in humid climates I would seal the attic and foam the rafters. I always include attics and crawl spaces inside the conditioned envelope of the house.

(Disregard this - I'll start a separate thread. Thanks, JDS.)

Definitely start a new thread. Highjacking is not kind. You can reference this thread in yours and vice versa.

I will just say a lot depends on your location and house configuration.