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funtony41
marks on vaulted ceiling

I have a vaulted ceiling and I can clearly see dark marks where the Roof studs are. They seem to be showing more where the ceiling meets the wall but some areas are all the way from wall to wall. Any ideas what this is from.Is it possible my roof is leaking or is it just a cheap paint job on the ceiling?

Timothy Miller
Re: marks on vaulted ceiling

photo would help. Burn allot of candles? have a gas insert with out the flu open?

sabo4545
Re: marks on vaulted ceiling

I have seen this on several houses where the drywall is attached directly to the rafters in a vaulted ceiling. The rafters are colder than the insulated spaces in-between in the winter and dust and dirt likely mixed with a little condensation sticks to these colder areas. You could try cleaning the areas which will help for a while but the dirt will return in the colder months. I would think the only way to prevent this would be to provide a thermal break between the rafters and drywall such as through rigid insulation place under the rafters and then the drywall on that. Of course that would be a major undertaking that probably isn't worth it. Perhaps an air purifier in that room may help the situation too. Hope this answers your question.

Mike

funtony41
Re: marks on vaulted ceiling

Thank you both as for candles, no we don't and no to the firplace as well. The marks are along the whole length of the wall. Here are some pics to help.

Timothy Miller
Re: marks on vaulted ceiling

Hi, thanks for the photos. I was thinking you might have soot accumulation on the ceiling but after the photos it's not soot.
Have you a humidifier on the furnace? Consider not adding the moisture in the winter. Are you in a cold climate? Consider investigating the air flow in the attic above the ceiling . There should be 2" of air space above the insulation between each sissier trusses. At the eve or soffit there needs to be a vent for each truss bay- amusing there is no attic space above the insulation. If the ventilation is not adequate the n condensation can cause this issue. The stains easily resolved with Kills white primer sealer , i would get a couple of spray cans as it has a strong odor and hard to apply with a brush but works great by spray can.The paint however does not stop future condensation issues.

ordjen
Re: marks on vaulted ceiling

I would concurr. The marks you see are caused by variations in the insulation. The colder areas are dampened with condensation and therefore attract airborn dirt. Were this ceiling over a bath, you would probably see water streaks running down the ceiling! Ultimately, better insulation would be the best cure, but expensive.

I would be somewhat concerned that airborn moisture is not working its way into the ceiling cavities. Is there a vapor barrier behind the drywall? If not , I would consider priming the entire ceiling with a primer that has a high "perm" rating. Such primers are available at good paint stores. They act as vapor barriers. I would then finish coat it with a high quality, low sheen paint, rather than the typical "ceiling" paint.

The other contributors are correct. You should keep the humidity down in winter. An electronic furnace filter might help also.

A. Spruce
Re: marks on vaulted ceiling

The problem is called "ghosting". As Ordjen described, the wall framing has less insulative value than insulation, so the joists are colder which attract condensation which attracts dust and dirt.

ordjen
Re: marks on vaulted ceiling

Another variation on this problem is where you will see small dark dots in the ceiling. This is where the metal drywall screws or nails are located. Metal transmits cold hundreds of times better than wood or drywall and therefore forms a tiny cold spot in on your ceiling or walls.

A. Spruce
Re: marks on vaulted ceiling
ordjen wrote:

Another variation on this problem is where you will see small dark dots in the ceiling. This is where the metal drywall screws or nails are located. Metal transmits cold hundreds of times better than wood or drywall and therefore forms a tiny cold spot in on your ceiling or walls.

Now you're just being a smar-T-pants! ;):p:D

Judith
Re: marks on vaulted ceiling

Hello - I recently (3 years ago) replaced my roof due to hail damage.  I now am getting significant ghosting on the ceiling area where there is no attic. This is a vaulted area with only enough room for the electrical.  The old roof was two layers - no longer code approved. Could the fact that the new roof is only one layer be causing the condensation that is probably making the ghosting? I have lived here 28 years and never had the ghosting until the new roof was installed. What can I do?

HandyAndyInMtAiry
Re: marks on vaulted ceiling

Judith,

Are you sure it is vaulted? Or a Cathedral ceiling? There is a difference. And that difference will be how the roof needs to be installed.

That is usually caused by not installing a quality vapor barrier(felt paper) on the sheeting. Or cheap quality shingles. Both will do things like that where hot meets cool. There should also be a small area between the sheeting and the back of the shingle to provide air movement.

There is only one option to fix this. This time, you select the quality of the products being used, the type and the installation methods. I suggest IKO shingles and material. Hail would not have bothered a roof covered with IKO roofing materials.

Andrew

Handy Andy In Mt Airy NC

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