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Message started by userID on Jan 14th, 2018, 10:20pm

Title: Spots on ceiling
Post by userID on Jan 14th, 2018, 10:20pm

Hello,

I've got spots on my ceiling in one of the bathrooms in my house. There are 3 spots in a straight line. They are perfectly round and very small. I am thinking they are the nail heads. The spots are cold and seem lightly damp. I am thinking it is condensation on the nail hands as they must act as a conduit for the cold to come in from the attic.

How can that be fixed? I cleaned my bathroom fan and I think it's about 15cfm under the HVI recommendations. It was very dirty, so I don't know if maybe it's not drawing out enough humidity from the air?

What should I do?

Title: Re: Spots on ceiling
Post by CWatters on Jan 15th, 2018, 5:56pm

Probably are nail heads but perhaps scratch through the paint to confirm or use a magnet or pipe/metal locator.

Insulating the attic might be worth doing.

Do you smoke or use candles in the bathroom? Sometimes the soot accumulates on nails and effect called ghosting.

Perhaps punch the heads below the surface slightly and fill the hole left.

Good paint for damp areas like bathroom ceilings is Zinsser Bulls Eye 123 primer-sealer and Zinsser Perma-White Matt.

Improving the ventilation should also help. Consider putting the extractor fan on an over run timer or perhaps a humidity sensor.



Title: Re: Spots on ceiling
Post by userID on Jan 15th, 2018, 9:59pm

First of all, thanks for the quick reply!

So I put a magnet near the spot, and it sticks, so there must be nails under there. I'd heard of ghosting before but I don't use candles in my bathroom and I don't smoke so it can't be that. I will definitely put the fan on an overrun timer or if I can, a humidity sensor...

Insulating the whole attic would be way too expensive, especially considering that this problem only occurs in one bathroom, on three nails. Would it be worth it to go check in the attic to see if there's a problem in the insulation between the attic and the bathroom? Could it be that?

Apart from putting the fan on overtime, what else should I try?

Thanks again!

Title: Re: Spots on ceiling
Post by thescruff on Jan 16th, 2018, 12:47am

Does the fan blow into the loft or is it ducted to outside.

Certainly worth checking in the loft to see whether drips are forming on the felt. Had this in my property, the condensation was running off the felt and soaking the insulation

Title: Re: Spots on ceiling
Post by woodsmith on Jan 16th, 2018, 9:28am

I'd try to dry the marks with a hairdryer, if it's damp it should fade very quickly, if not you could brush some stain block over the marks and see if that works.

Title: Re: Spots on ceiling
Post by userID on Jan 16th, 2018, 1:36pm

I'll look at those two things as soon as possible! Thanks

Title: Re: Spots on ceiling
Post by CWatters on Jan 18th, 2018, 7:16am

I'd check there is enough insulation above the bathroom. If there isn't and the bathroom ceiling is a bit cold the nails will be the first to pick up some condensation then mould.

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