Dehumidifier in a newly plastered room.

[CluelessDIYer1]

I've been told this is a no-no, but from talking to plasterers, their stories of customers wrecking their work were lining up a row of dehumidifiers & having them on full whack.

I was talking to another guy who's a fairly competent DIYer (unlike myself). Our living room seems to have damn near dried out, minus a few patches where bonding was used.
The small section at the rear of the kitchen has (after 1-2 weeks) finally started drying in patches, but it gets almost no sunlight. Of a weekend when we're there, we have the side door open & the rear door open with the living room doors shut so that there's a through-flow of air to try & dry the wall out. It's getting there but very slow.

This chap i spoke to said about putting a dehumidifier in there. I mentioned my concern, especially as my mum did this on the stairs of her house on day 1 & it cracked the plaster.
He said that it's ok to put it on its low setting & that plaster will crack anyway, even when drying naturally.


So tonight i put the dehumidifier in the corner of the dining room - away from the patch at the rear of the kitchen by about 6mtr ish & away from the living room by a reasonable distance. I've left the doors separating the living room & dining room/kitchen open & the door from the living room to the hall open. I left the dehumidifier on its lowest setting.


So i just wanted to check what the experts reckon. Would this be ok since the dehumidifier is away from the plaster a reasonable amount & it's on its lowest setting?
Or is it a case of no dehumidifier under any circumstance?

Just wanted to put my mind at ease



EDIT: And what about re-fitting & turning the radiators on in addition to/instead of the dehumidifier?
Our radiators have a setting of 0, frost & then 1-5. Would they be fine stuck on setting #1 as well as the dehumidifier, or would that be too much? Would either be too much or would 1/both of them be fine?

Just wanting to speed things up without causing problems.

 

[noseall]

Put the heating on and open some windows.

Plaster will happily cure at raised temperatures. I know because I plastered out a conny in the summer once and it must have been over 100 degrees in there!

However, it will not tolerate rapid drying out i.e. when the summer sun is directly on the surface, extreme high suction backgrounds or when using aggressive man-made drying methods.

Once the plaster has hardened it will safely cure at room temperature.

 

[CluelessDIYer1]

Well for varying patches it'll have been about 2-3 weeks now.

The plasterer advised to silicone seal around the windows before using them. Decorators caulk on here was mentioned for painting purposes, but to be honest i'm not bothered about a beat of white around the windows. IMO it doesn't look bad.

'for now' would the dehumidifier where i said be ok? I don't intend on leaving it there forever & a day, but just short term? Want to get the walls painted before the radiators go back on.



Also, 'turn the heating on' - to what level? Like i say, ours have a 0-5 setting. I'm taking that setting 1 would be fine, but how high could you go with it still being fine? I've done some googling about plaster drying out & the like & i often see people saying 'you can get away with'. Well i don't want to 'get away with' as that implies the actions being borderline. I want things to be fine.

 

[JohnD]

open the windows.

fresh air dries walls, not heat.

 

[CluelessDIYer1]

Thanks. Plan on sealing up the windows today & then doing that with the windows.

Still, i hope i don't come across as being rude (as i don't mean to) but will the dehumidifier used as i described be detrimental or will it be ok? I fully expect if it was turned on to its highest setting & turned all the way up that this would be a bad thing, but on the lowest setting on the lowest stat setting .... ?

 

[JohnD]

the weather is now very mild and dry (round here anyway) so I wouldn't spend money on running a dehumidifier, just open the windows. If the house is unattended, and you have to close them, open the loft hatch and internal doors. Water vapour is lighter than air so it will rise up and escape.

Is the plaster pale pink yet, or have you still got chocolate brown patches?

If you have any wet bits, put a household fan to blow on them.

If need be, you can run the dehumidifier for a couple of days before you start painting.

Dulux Trade Supermatt is a non-vinyl paint which allows the plaster to continue drying out. It is quite cheap, especially in white, makes the place look respectable, and will give a good surface to redecorate on later (it is not very hardwearing as a finish).

 

[NickB_99]

CD1 - is this drying out the same room as your post with the damp circles in the lower half of the wall?

 

[CluelessDIYer1]

the weather is now very mild and dry (round here anyway) so I wouldn't spend money on running a dehumidifier, just open the windows. If the house is unattended, and you have to close them, open the loft hatch and internal doors. Water vapour is lighter than air so it will rise up and escape.

Is the plaster pale pink yet, or have you still got chocolate brown patches?

If you have any wet bits, put a household fan to blow on them.

If need be, you can run the dehumidifier for a couple of days before you start painting.

Dulux Trade Supermatt is a non-vinyl paint which allows the plaster to continue drying out. It is quite cheap, especially in white, makes the place look respectable, and will give a good surface to redecorate on later (it is not very hardwearing as a finish).

The plaster is pink. Here are some photos: //www.diynot.com/forums/plaste...nd-new-dotdab-walls-totally-knackered.396054/

I've purposely been leaving all interior doors open, but didn't think about the loft. Thanks.

There are still brown patches yes:


This was where bonding was used. I don't know if salts are showing through too:


I have noticed the mention of Dulux Trade Supermatt before when reading about painting new plaster...
http://www.diy.com/nav/decor/paint-...-SuperMatt-Paint-White-10299014?skuId=9260622 £30 for 5ltrs.

Can i ask then - why does everyone seem to suggest Dulux Trade? I've read you need to do a mist coat. Our room is 6.7mtrx3.5mtr. I've read some even suggest 2 mist coats whereas others scoff at that idea.

I was in Wilkinsons today & their matt emulsion was £6 for 5 litres. That's £24 saving.

Ok i'm not even trying to suggest that the quality will be on a par with the Dulux stuff, but if you're just watering it down & misting it, then why would the £6 Wilkinsons matt emulsion be so bad? Is there a reason to spend the extra £24? And then spend more money on top of that for the top coat?


Don't get me wrong - i'm not trying to say what you or anyone else here says is wrong as i know sod all so wouldn't dare. I'm just trying to understand why the need to spend £30 when it seems £6 would do the same (matt emulsion) & you could then spend £30 on the top coat, rather than £30 on the misting paint & £30 on the top coat?

 

[CluelessDIYer1]

CD1 - is this drying out the same room as your post with the damp circles in the lower half of the wall?

Sort of - it's all downstairs. I did a 'perfect' layout map for you in paint Don't laugh




The living room is 6.7mtr long x 3.5mtr wide. The drawing is not to any ratio

The dehumidifier is placed where the red X is. All doors have been kept open. There is no door between kitchen & diner, just a walkway. The patio doors are right behind the red X.

The entire living room has been plastered as has the wall in the kitchen to the rear of the dotted line (the dotted line is the french doors which are left open).

 

[JohnD]

most emulsion paints contain vinyl. Supermatt doesn't so it is porous and plaster can dry out through it.

could there be a water leak behind that wet patch?

if you are running a dehumidifier in a room, you have to shut the doors and windows or it will try to dehumidify the world.

 

[CluelessDIYer1]

most emulsion paints contain vinyl. Supermatt doesn't so it is porous and plaster can dry out through it.

Ahh thanks. I didn't know that.

Is there a way to tell whether it contains vinyl? Would it say on the rear of the tin at all?

could there be a water leak behind that wet patch?

Behind that wet patch is the party wall. On the other side of that wall in the neighbours living room it is piddle wet through & i mean piddle wet - it's dripping down the walls, HOWEVER, this is on the OTHER side of the chimney breast & not the photo i just showed you.

We wondered if the flaunching on the chimney was possibly contributing since it was goosed. We've had this done in January.

if you are running a dehumidifier in a room, you have to shut the doors and windows or it will try to dehumidify the world.

I know, but my logic behind doing it as i did (whether correct or not) is that if it's in a room with doors shut, it will concentrate the sucking water out of the room with the plaster & may dry it out TOO quick. If i have the doors open, then it's taking over a wide area & will draw it out slower - less chance of cracking??




On the topic of household fans - would you just stick it in the room, or would you direct at the wet patch?[/quote]

 

[JohnD]

the dehumidifier takes water out of the air. If you have a fan, or if it has an outlet for the warm dry air, point it at the wet patch. Air moving over the surface helps draw the water out of the surface and into the air. If the air is still it takes longer. cf. a washing line.

 

[JohnD]

Behind that wet patch is the party wall. On the other side of that wall in the neighbours living room it is piddle wet through & i mean piddle wet - it's dripping down the walls

either the neighbours have a leak, or they are in the habit of draping wet washing around their home or over radiators.

 

[CluelessDIYer1]

either the neighbours have a leak, or they are in the habit of draping wet washing around their home or over radiators.

They have the same issue as us & many of us on our street. I haven't been door-to-door but i'm told the houses on the ends of the street are ok but those in the middle (i'm as the road starts to climb again) suffer badly from water under the floorboards in the living room. We have a sump pump fitted, as do our neighbours.

Our damp surveyor said this is causing moist air, getting into the walls above the DPC & shooting up.

Still, you can SEE the water forming on their walls whereas ours was just soft plaster.

Our neighbour asked our plasterers if they'd been using (insert name for tool that knocks plaster off - a heavy tool, not a bolster) as his electricity kept tripping out.

Turned out the mains, once he took it out of the wall near the chimney, was piddle-wet through & rusty as hell. Kept tripping it out.

The tops of the walls are fine, so surely it has to be the water below the floorboards.

The sub floor is 1mtr deep. From the reactions of builders & plasterers i've spoken to, this is quite a drop (as in more than usual).

 

[JohnD]

you could get the water co to test the water; they can tell if it is from a mains leak (chlorinated) or a sewer leak (soapy) or just groundwater. You might be lucky.